Device and method for collecting micro-plastics in water body in situ

Abstract

The invention discloses a device and a method for in-situ collection of water body micro-plastics, the device for in-situ collection of water body micro-plastics comprises a water pumping device and a suction filtration device, the water pumping device comprises a submersible pump, a flowmeter, a filter protection net, a ballast, a water outlet pipe and a scale rope; the suction filtration device comprises an inlet bottle, a metal filter membrane, a vacuum pump and a water outlet bottle; a target water body is pumped into the closed suction filtration device through the submersible pump, micro-plastics in the water body are left on the metal filter membrane under the action of air pressure, the water subjected to suction filtration is discharged through the water outlet in the lower portion of the side face of the water outlet bottle, the metal filter membrane is taken down for sealed storage, and research can be conducted only by taking back the metal filter membrane; according to the invention, the transportation and storage troubles of a large amount of water samples can be solved, the scientific research cost is effectively reduced, the limitation that trawl collection is only suitable for surface water sampling can be solved, water samples at different depths can be accurately collected, a large amount of sample data can be obtained, and great help is provided for deeper research.

Description

Technical Field

[0001] The present invention belongs to the technical field of monitoring new pollutants in the ecological environment, and in particular relates to a device and method for in-situ collection of microplastics in water. Background Art

[0002] Thompson et al. first proposed the concept of "microplastics" in 2004. Microplastics are already common on land and in the oceans of various regions around the world, and have even been detected in polar glaciers due to their small size, large specific surface area, strong ability to adsorb pollutants and migration. Microplastics have been detected in humans, animals and plants. As one of the new pollutants, the impact of microplastics on the earth's environment and human health has attracted the attention of scholars at home and abroad, and certain research results have been achieved. As an important pathway for the transmission and migration of microplastics, water bodies are essential for tracing the source and reducing plastics by being able to detect microplastics in water bodies conveniently and effectively. Collecting microplastics is a key step before detection, which is of great significance for the prevention and control of microplastic pollution.

[0003] However, the collection and detection methods of microplastics in water bodies are still in the exploratory stage, and there is no unified standard. Existing studies have shown that collecting microplastics in water bodies at a sampling point requires a large number of water samples, and some literature has shown that the required water volume is at least 8L to obtain more accurate sample data. Therefore, in order to make the microplastic detection results accurate and effective, a large number of water samples need to be collected. However, a large number of water samples are not easy to collect, store and transport. How to collect microplastics in water bodies in situ is a key step in studying microplastic pollution.

[0004] At present, the existing method for in situ collection of microplastics mainly uses trawl collection, but it is more suitable for large-scale surface water sampling and requires a large amount of pure water to flush the trawl. A large number of water samples still need to be collected and stored on site. It cannot fundamentally solve the problem of in situ sampling and needs further improvement. Summary of the invention

[0005] The present invention provides a device and method for in-situ collection of microplastics in water, which can solve the problems of the prior art.

[0006] To solve the above problems, the technical solution provided by the present invention is as follows:

[0007] An embodiment of the present invention provides a device for in-situ collection of microplastics in water, comprising a pumping device (1) and a filtration device (2), wherein the pumping device (1) comprises a submersible pump (3), a flow meter (4), a first filter protection net (5), a second filter protection net (6), a ballast (7), a water outlet pipe (8) and a measuring rope (9), wherein the submersible pump (3) is arranged below a water surface line (S1), the submersible pump (3) is arranged in the first filter protection net (5), and the first filter protection net (5) is arranged in the second filter protection net (6); the ballast (7) is connected to the bottom of the submersible pump (3), and the measuring rope (9) is connected to the top of the submersible pump (3); the water outlet pipe (8) is connected to the side of the submersible pump (3), and the water outlet pipe (8) extends to the water surface line (S1), and the flow meter (4) is arranged on the water outlet pipe (8);

[0008] The suction filtration device (2) is arranged above the water surface line (S1), and the suction filtration device (2) comprises an inlet bottle (10), a metal filter membrane (11), a vacuum pump (12) and a water outlet bottle (13); the bottom of the inlet bottle (10) is connected to the water outlet bottle (13) through the metal filter membrane (11), the top of the inlet bottle (10) is connected to the water outlet pipe (8), the upper left side of the water outlet bottle (13) is connected to the vacuum pump (12) through a latex tube (14), the lower right side of the water outlet bottle (13) is provided with a water outlet (15), and the end of the water outlet (15) is provided with a water-permeable and air-tight membrane (16) to ensure normal water flow but no air permeability.

[0009] In an optional embodiment of the present invention, the submersible pump (3) is a self-priming booster pump, with a head of 55m, a suction head of 9m, an inlet and outlet diameter of 16mm, and a maximum flow rate of 500L / h.

[0010] In an optional embodiment of the present invention, the flow meter (4) is an electronic flow meter, and the outer diameter of the inlet and outlet at both ends thereof is 20 mm.

[0011] In an optional embodiment of the present invention, the first filter protection net (5) has a pore size of 5 mm and a length, width and height of 300×300×500 mm.

[0012] In an optional embodiment of the present invention, the second filter protection net (6) has a pore size of 5 cm, and a length, width and height of 320×320×520 mm.

[0013] In an optional embodiment of the present invention, the ballast (7) is a cubic iron block with a size of 86×86×86 mm and a weight of 5 kg.

[0014] In an optional embodiment of the present invention, the diameter of the water inlet and outlet of the inlet bottle (10) is 15 mm, the metal filter membrane (11) is a metal membrane with a pore size of 0.45 um or other pore size less than 5 mm, and the pore size of the metal membrane can be selected according to the specific research content; the water outlet bottle (13) is a conical glass bottle with a volume of 2L, and the diameter of its upper air vent is 15 mm, and the diameter of the water outlet (15) at the lower right side surface is 15 mm.

[0015] In an optional embodiment of the present invention, a first valve (8-1) is provided on the water outlet pipe (8), a second valve (10-1) is provided on the side leakage pipe of the inlet bottle (10), a third valve (14-1) is provided on the latex tube (14), and a fourth valve (15-1) is provided on the lower water outlet (15) on the right side of the water outlet bottle (13).

[0016] The present invention also provides a method for in-situ collection of microplastics in water, which is implemented using a device for in-situ collection of microplastics in water as in the above embodiment, and includes the following steps:

[0017] Step S1, assembling a pumping device (1), the pumping device (1) is placed below the water surface line (S1); the pumping device (1) comprises a submersible pump (3), a flow meter (4), a first filter protection net (5), a second filter protection net (6), a ballast (7), a water outlet pipe (8) and a measuring rope (9); the measuring rope (9) is connected to the top of the submersible pump (3), and whether the required sampling depth is reached is judged according to the scale of the measuring rope;

[0018] Step S2, assembling a suction filtration device (2), wherein the suction filtration device (2) is placed on a sampling vessel or on a shore, and the suction filtration device (2) comprises an inlet bottle (10), a metal filter membrane (11), a vacuum pump (12) and a water outlet bottle (13); the water pumping device (1) is connected to a flow meter (4) via a water outlet pipe (8), and then connected to the suction filtration device (2);

[0019] Step S3, using the second filter protection net (6) to intercept impurities with a particle size greater than 5 cm in the water to prevent damage to the submersible pump (3), using the first filter protection net (5) to filter out substances in the water that are greater than 5 mm and do not meet the requirements of microplastics. Under the action of the submersible pump (3), the target water flows through the flow meter (4) through the outlet pipe (8) to measure the water volume, and then the target water enters the inlet bottle (10) through the first valve (8-1), and then passes through the filtering action of the metal filter membrane (11), so that the microplastic molecules are attached to the upper side of the metal filter membrane, and finally the metal filter membrane is removed and sealed for storage. It only needs to be taken back for research. The metal filter membrane with microplastics attached ( 11) is more convenient for transportation and storage, avoiding the problem of transporting and storing a large number of water samples; wherein, the function of the vacuum pump (12) is to evacuate the air in the water outlet bottle (13), so that the water sample can be filtered smoothly under the action of gravity and pressure, and each study needs to take at least 8L of water sample, the volume of the water outlet bottle (13) is small, and the filtered water needs to be emptied gradually, so there is a water outlet (15) at the lower right side of the water outlet bottle (13), but because the water outlet bottle (13) needs to maintain a vacuum state during use, a fourth valve (15-1) and a water-permeable and air-impermeable membrane (16) are arranged on the outer side of the water outlet (15) at the lower right side of the water outlet bottle (13).

[0020] Beneficial effect: The embodiment of the present invention provides a device and method for collecting microplastics in water in situ, the device for collecting microplastics in water in situ includes a pumping device and a filtration device, the pumping device includes a submersible pump, a flow meter, a filter protection net, a ballast, a water outlet pipe and a scale rope; the filtration device includes an inlet bottle, a metal filter membrane, a vacuum pump and a water outlet bottle; the present invention uses a submersible pump to pump the target water into a closed filtration device, and under the action of air pressure, the microplastics in the water body are left on the metal filter membrane, the filtered water is discharged through the lower water outlet on the side of the water outlet bottle, the metal filter membrane is removed and sealed for storage, and only the metal filter membrane needs to be taken back for research. The present invention can not only solve the trouble of transporting and storing a large number of water samples, effectively reduce the cost of scientific research and reduce physical work, but also solve the problem of collecting microplastics in situ, solve the limitation that the current trawl collection of microplastics in situ is only suitable for surface water sampling, can accurately collect water samples of different depths, obtain a large amount of sample data, and provide great help for deeper research. At the same time, the in-situ collection device for microplastics in water is simple in structure and operation, easy to transport, and can also be adjusted by selecting ballast of different weights according to the depth of water sampling, so as to obtain sample data at different depths at the same sampling point, which has a deeper meaning for scientific research. In addition, the water samples are returned after sampling, reducing the impact on the original ecology. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A schematic diagram of the structure of a device for in-situ collection of microplastics in water provided in an embodiment of the present application.

[0023] Figure 2 A schematic diagram of a pumping device in a device for in-situ collection of microplastics in water provided in an embodiment of the present application.

[0024] Figure 3 A schematic diagram of a filtration device in a device for in-situ collection of microplastics in water provided in an embodiment of the present application.

[0025] Figure 4 A schematic diagram of a first filter protection net in a water pumping device provided in an embodiment of the present application.

[0026] Figure 5 A schematic diagram of a second filter protection net in a water pumping device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0028] like Figure 1 , Figure 2 and Figure 3 As shown, an embodiment of the present invention provides a device for in-situ collection of microplastics in water, including a pumping device 1 and a filtration device 2. The pumping device 1 includes a submersible pump 3, a flow meter 4, a first filter protection net 5, a second filter protection net 6, a ballast 7, an outlet pipe 8 and a measuring rope 9. The submersible pump 3 is arranged below the water surface line S1, the submersible pump 3 is arranged in the first filter protection net 5, and the first filter protection net 5 is arranged in the second filter protection net 6; the ballast 7 is connected to the bottom of the submersible pump 3, and the measuring rope 9 is connected to the top of the submersible pump 3; the outlet pipe 8 is connected to the side of the submersible pump 3, and the outlet pipe 8 extends to the water surface line S1, and the flow meter 4 is arranged on the outlet pipe 8.

[0029] The filtration device 2 is arranged above the water surface line S1, and the filtration device 2 includes an inlet bottle 10, a metal filter membrane 11, a vacuum pump 12 and a water outlet bottle 13; the bottom of the inlet bottle 10 is connected to the water outlet bottle 13 through the metal filter membrane 11, the top of the inlet bottle 10 is connected to the water outlet pipe 8, the upper left side of the water outlet bottle 13 is connected to the vacuum pump 12 through a latex tube 14, the lower right side of the water outlet bottle 13 is provided with a water outlet 15, and the end of the water outlet 15 is provided with a water-permeable and airtight membrane 16 to ensure normal water flow but no air permeability.

[0030] Submersible pump 3 is a self-priming booster pump with a head of 55m, a suction head of 9m, an inlet and outlet diameter of 16mm, and a maximum flow rate of 500L / h. Flow meter 4 is an electronic flow meter with an inlet and outlet outer diameter of 20mm at both ends. Figure 4 As shown, the first filter protection net 5 has a pore size of 5 mm and a length, width and height of 300×300×500 mm. Figure 5 As shown, the aperture of the second filter protection net 6 is 5 cm, and its length, width and height are 320×320×520 mm. The ballast 7 is a cubic iron block with a size of 86×86×86 mm and a weight of 5 kg.

[0031] The diameter of the water inlet and outlet of the inlet bottle 10 is 15mm. The metal filter membrane 11 is a metal membrane with a pore size of 0.45um or other pore sizes less than 5mm. Metal membranes with corresponding pore sizes can be installed according to requirements. Since the metal filter membrane 11 is a relatively delicate device, the selection of the filter membrane pore size must be cautious in order to collect microplastics of different sizes. The water outlet bottle 13 is a conical glass bottle with a volume of 2L, and the diameter of its upper vent is 15mm, and the diameter of the water outlet 15 at the lower right side is 15mm.

[0032] Among them, a first valve 8-1 is provided on the water outlet pipe 8, a second valve 10-1 is provided on the side leakage pipe of the inlet bottle 10, a third valve 14-1 is provided on the latex tube 14, and a fourth valve 15-1 is provided on the water outlet 15 at the lower right side of the water outlet bottle 13.

[0033] The embodiment of the present invention further provides a method for in-situ collection of microplastics in water, which is implemented by using a device for in-situ collection of microplastics in water as in the above embodiment, and includes the following steps:

[0034] Step S1, assemble the pumping device 1, and place the pumping device 1 below the water surface line S1; the pumping device 1 includes a submersible pump 3, a flow meter 4, a first filter protection net 5, a second filter protection net 6, a ballast 7, a water outlet pipe 8 and a measuring rope 9; the measuring rope 9 is connected to the top of the submersible pump 3, and the scale of the measuring rope is used to determine whether the required sampling depth has been reached;

[0035] Step S2, assembling the filtration device 2, which is placed on the sampling ship or on the shore, that is, the filtration device 2 is set above the water surface line S1; the filtration device 2 includes an inlet bottle 10, a metal filter membrane 11, a vacuum pump 12 and a water outlet bottle 13; the pumping device 1 is connected to the flow meter 4 through the outlet pipe 8, and then connected to the filtration device 2;

[0036] Step S3, use the second filter protection net 6 to intercept impurities with a particle size greater than 5 cm in the water to prevent damage to the submersible pump 3, and use the first filter protection net 5 to filter out substances in the water that are greater than 5 mm and do not meet the requirements of microplastics. Under the action of the submersible pump 3, the target water flows through the flow meter 4 through the outlet pipe 8 to measure the water volume, and then the target water enters the inlet bottle 10 through the first valve 8-1, and then passes through the filtering action of the metal filter membrane 11 to attach the microplastic molecules to the upper side of the metal filter membrane. Finally, the metal filter membrane is removed and sealed for storage. It only needs to be taken back for research. The metal filter membrane attached with microplastics 11 is more convenient for transportation and storage, avoiding the problem of transportation and storage of a large number of water samples; wherein, the function of the vacuum pump 12 is to evacuate the air in the water outlet bottle 13, so that the water sample can be successfully filtered under the action of gravity and pressure, and each study needs to take at least 8L of water sample, the volume of the water outlet bottle 13 is small, and the filtered water needs to be emptied gradually, so there is a water outlet 15 at the lower right side of the water outlet bottle 13, but because the water outlet bottle 13 needs to maintain a vacuum state during use, a fourth valve 15-1 and a water-permeable and air-tight membrane 16 are arranged on the outer side of the water outlet 15 at the lower right side thereof.

[0037] As mentioned above, the pumping device 1 is an important component for extracting water samples in the present invention. Part of the outlet pipe 8 between the submersible pump 3 and the flow meter 4 is a latex tube. When the depth of sample collection is required to be large, a submersible pump with a larger lift must be selected.

[0038] The filtration device 2 is the place where the present invention collects microplastics in water. The metal filter membrane 11 must be installed firmly to prevent it from falling during the filtration process. Each water outlet and the top of the inlet bottle must be sealed. The vacuum pump 12 is connected through a latex tube 14.

[0039] The implementation process of the present invention is as follows: when the sampling point is located in the middle of a river, lake or wetland, the water microplastic collection process needs to be completed on a boat. First, after the overall device is assembled, water should be pumped out to check the tightness of the device. Then, according to the required sampling depth, prepare the scale rope scale and lower the submersible pump 3. If the water depth is large and the weight of the device itself is less than the buoyancy at this point, a ballasted load 7 needs to be added to the bottom of the submersible pump 3; turn on the power to draw water, always observe the value of the flow meter 4, and control the water volume through the valve in time; the water sample enters the inlet bottle 10 through the valve. Since the pore size of the metal filter membrane 11 is very small, the water sample cannot flow out smoothly. At this time, a vacuum pump can be used to evacuate the air in the water outlet bottle 13, and a strong pressure difference is formed on the upper and lower sides of the metal filter membrane 11, and water molecules can be under the pressure. At the same time, since the volume of the water outlet bottle 13 is much smaller than the amount of water sample required to be collected, it needs to be released gradually through the water outlet 15 at the lower right side of the water outlet bottle 13. However, in order to avoid the impact of the filtered water on the microplastic content in the original water body, the water after each sampling needs to be returned after the sampling is completed to ensure the accuracy of the research; finally, you only need to take out the metal filter membrane 11, seal it and take it back to the laboratory for further testing, which greatly reduces the tasks in the research process.

[0040] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A device for in-situ collection of microplastics in water, characterized in that: The invention comprises a pumping device (1) and a filtration device (2), wherein the pumping device (1) comprises a submersible pump (3), a flow meter (4), a first filter protection net (5), a second filter protection net (6), a ballast (7), a water outlet pipe (8) and a measuring rope (9), wherein the submersible pump (3) is arranged below the water surface line (S1), the submersible pump (3) is arranged in the first filter protection net (5), and the first filter protection net (5) is arranged in the second filter protection net (6); the ballast (7) is connected to the bottom of the submersible pump (3), and the measuring rope (9) is connected to the top of the submersible pump (3); the water outlet pipe (8) is connected to the side of the submersible pump (3), and the water outlet pipe (8) extends to the water surface line (S1), and the flow meter (4) is arranged on the water outlet pipe (8); The suction filtration device (2) is arranged above the water surface line (S1), and the suction filtration device (2) comprises an inlet bottle (10), a metal filter membrane (11), a vacuum pump (12) and a water outlet bottle (13); the bottom of the inlet bottle (10) is connected to the water outlet bottle (13) through the metal filter membrane (11), the top of the inlet bottle (10) is connected to the water outlet pipe (8), the upper left side of the water outlet bottle (13) is connected to the vacuum pump (12) through a latex tube (14), the lower right side of the water outlet bottle (13) is provided with a water outlet (15), and the end of the water outlet (15) is provided with a water-permeable and air-tight membrane (16) to ensure normal water flow but no air permeability.

2. The device for in-situ collection of microplastics in water according to claim 1, characterized in that: The submersible pump (3) is a self-priming booster pump, with a head of 55m, a suction head of 9m, an inlet and outlet diameter of 16mm, and a maximum flow rate of 500L / h.

3. The device for in-situ collection of microplastics in water according to claim 2, characterized in that: The flow meter (4) is an electronic flow meter, and the outer diameters of the inlet and outlet at both ends are 20 mm.

4. The device for in-situ collection of microplastics in water according to claim 3, characterized in that: The first filter protection net (5) has a pore size of 5 mm and a length, width and height of 300×300×500 mm.

5. The device for in-situ collection of microplastics in water according to claim 4, characterized in that: The second filter protection net (6) has a pore size of 5 cm and a length, width and height of 320×320×520 mm.

6. The device for in-situ collection of microplastics in water according to claim 5, characterized in that: The ballast (7) is a cubic iron block with a size of 86×86×86 mm and a weight of 5 kg.

7. The device for in-situ collection of microplastics in water according to claim 6, characterized in that: The inlet and outlet diameters of the inlet bottle (10) are 15 mm, and the metal filter membrane (11) is a metal membrane with a pore size of 0.45 um or other pore size less than 5 mm. The pore size of the metal membrane can be selected according to the specific research content; the water outlet bottle (13) is a conical glass bottle with a volume of 2L, and the diameter of its upper air vent is 15 mm, and the diameter of the water outlet (15) at the lower right side is 15 mm.

8. The device for in-situ collection of microplastics in water according to claim 7, characterized in that: The water outlet pipe (8) is provided with a first valve (8-1), the side leakage pipe of the inlet bottle (10) is provided with a second valve (10-1), the latex tube (14) is provided with a third valve (14-1), and the water outlet (15) at the lower right side of the water outlet bottle (13) is provided with a fourth valve (15-1).

9. A method for in-situ collection of microplastics in water, implemented by using a device for in-situ collection of microplastics in water as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1, assembling a pumping device (1), the pumping device (1) is placed below the water surface line (S1); the pumping device (1) comprises a submersible pump (3), a flow meter (4), a first filter protection net (5), a second filter protection net (6), a ballast (7), a water outlet pipe (8) and a measuring rope (9); the measuring rope (9) is connected to the top of the submersible pump (3), and whether the required sampling depth is reached is judged according to the scale of the measuring rope; Step S2, assembling a suction filtration device (2), wherein the suction filtration device (2) is placed on a sampling vessel or on a shore, and the suction filtration device (2) comprises an inlet bottle (10), a metal filter membrane (11), a vacuum pump (12) and a water outlet bottle (13); the water pumping device (1) is connected to a flow meter (4) via a water outlet pipe (8), and then connected to the suction filtration device (2); Step S3, using the second filter protection net (6) to intercept impurities with a particle size greater than 5 cm in the water to prevent damage to the submersible pump (3), using the first filter protection net (5) to filter out substances in the water that are greater than 5 mm and do not meet the requirements of microplastics. Under the action of the submersible pump (3), the target water flows through the flow meter (4) through the outlet pipe (8) to measure the water volume, and then the target water enters the inlet bottle (10) through the first valve (8-1), and then passes through the filtering action of the metal filter membrane (11), so that the microplastic molecules are attached to the upper side of the metal filter membrane, and finally the metal filter membrane is removed and sealed for storage. It only needs to be taken back for research. The metal filter membrane with microplastics attached ( 11) is more convenient for transportation and storage, avoiding the problem of transporting and storing a large number of water samples; wherein, the function of the vacuum pump (12) is to evacuate the air in the water outlet bottle (13), so that the water sample can be filtered smoothly under the action of gravity and pressure, and each study needs to take at least 8L of water sample, the volume of the water outlet bottle (13) is small, and the filtered water needs to be emptied gradually, so there is a water outlet (15) at the lower right side of the water outlet bottle (13), but because the water outlet bottle (13) needs to maintain a vacuum state during use, a fourth valve (15-1) and a water-permeable and air-impermeable membrane (16) are arranged on the outer side of the water outlet (15) at the lower right side of the water outlet bottle (13).

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