Portable filtering device for micro-plastics in surface water sample

Abstract

The utility model relates to the technical field of environmental monitoring, and discloses a portable filtering device for micro-plastics in a surface water sample, which comprises a micro-plastic double-layer filtering structure, a filtering bottle and a vacuum pump which are detachably connected, the micro-plastic double-layer filtering structure comprises an upper filtering cup, an upper-layer filtering net, a middle filtering cup, a lower-layer filtering net and a filtering cup base funnel which are sequentially stacked and connected from top to bottom and internally communicated; the upper part of the upper filter cup is an open opening, and a funnel pipe is arranged at the bottom of the filter cup base funnel and penetrates through the bottle neck plug to reach the hollow position inside the filter bottle. According to the utility model, the structure is integrally simplified, a detachable connection mode is adopted, the volume is small, each part is easy and quick to disassemble and assemble and is portable, the requirements of on-site, daily, batch and diversified filtration and collection of micro-plastics in surface water can be met, and the device is simple and convenient to operate, short in filtration time and low in cost.

Description

Technical Field

[0001] This utility model relates to the field of environmental monitoring technology, specifically to a portable filtration device for microplastics in surface water samples. Background Technology

[0002] Microplastics refer to plastic particles and fragments with a length or diameter of 5 mm or less, including granules, microfibers, particles, foams, or films. In recent years, microplastics have become a new pollutant of great concern in surface water. Microplastics in surface water have characteristics such as large specific surface area, low density, strong hydrophobicity, and easy migration with water flow. They can adsorb hydrophobic organic matter to form organic complexes, increasing the complexity of water pollution as they migrate with water flow. Small-scale microplastics can also physically harm organisms through ingestion, thus affecting their physiological characteristics. Due to the diverse composition, varied shapes, and low sample volume of microplastics in surface water, the specific sampling and filtration treatment methods directly determine the detection quality and efficiency of microplastic samples. Depending on the actual needs, different sampling methods and filtration operations are often adopted, thus requiring various filtration and collection devices.

[0003] Currently, the main sampling methods for microplastics in surface water are trawl netting and water sampler filtration. Trawl netting is cumbersome, complex, and exposes samples to the environment for extended periods. Traditional water sampler filtration requires collecting 5L of water and then vacuum filtering it in the laboratory. The 0.45 μm aqueous membrane used in the filtration process results in a long filtration time, requiring frequent membrane replacements. This is not conducive to the on-site, routine, batch, and diverse testing needs for microplastics in surface water, nor can it meet the filtration and collection requirements for different detection qualities (collection scales).

[0004] In recent years, scholars have proposed new solutions to the problem of microplastic filtration in water samples. For example, Chinese utility model CN214737909U discloses a microplastic collection device for natural water bodies, including a filtration and collection device. This utility model can quickly and effectively collect microplastic samples from water bodies for laboratory analysis and testing, and can be used to scientifically evaluate the degree of microplastic pollution in water bodies. However, this device includes a support frame and other components, has many parts, and is relatively large, making it impossible to carry to the water sampling site for operation. It also cannot meet the requirements for on-site, routine, batch, and diversified (meeting various detection qualities and different collection scales) filtration and collection of microplastics in surface water. Utility Model Content

[0005] The purpose of this invention is to provide a portable filtration device for microplastics in surface water samples. Through improved design of the structure and cooperation of multiple components, it is easy to assemble and disassemble quickly and is portable, so as to meet the requirements of on-site, daily, batch and diversified (meeting multiple detection qualities and different collection scales) filtration and collection of microplastics in surface water. Moreover, it is easy to operate, has a short filtration time and low cost, and solves the technical problems existing in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A portable filtration device for microplastics in surface water samples, characterized in that it includes a detachably connected microplastic double-layer filtration structure, a filter bottle, and a vacuum pump.

[0008] The filter bottle is provided with an air extraction pipe and a drain pipe on its side wall; a bottle neck plug is provided in the internal channel at the bottle neck to seal the bottle neck.

[0009] The vacuum pump is connected to the suction pipe of the filter bottle via a flexible hose;

[0010] The microplastic dual-layer filtration structure comprises, from top to bottom, a series of interconnected components: an upper filter cup, an upper filter screen, a middle filter cup, a lower filter screen, and a filter cup base funnel.

[0011] Both the upper and middle filter cups are cylindrical containers with open openings at the top and bottom.

[0012] The upper opening of the middle filter cup is provided with an upper grooved filter screen to support the upper filter screen;

[0013] The filter cup base funnel has a lower groove filter screen at the upper opening and a funnel tube at the bottom; the lower groove filter screen supports the lower filter screen, and the funnel tube passes through the neck plug to reach the hollow position inside the filter bottle.

[0014] The upper filter cup has an open opening at the top and an upper threaded sealing sleeve at the bottom. The internal thread on the upper threaded sealing sleeve connects with the external thread on the upper grooved filter screen and seals the connection.

[0015] The upper filter screen is set inside the upper threaded sealing sleeve and directly above the groove on the upper surface of the upper grooved filter screen. The upper threaded sealing sleeve and the upper grooved filter screen simultaneously hold and flatten the lower filter screen, forming the first layer of microplastic filtration structure.

[0016] The upper filter screen is a nylon mesh screen with a mesh diameter of 5 mm (other mesh sizes can also be selected according to the testing quality requirements).

[0017] The upper part of the middle filter cup is provided with an open opening for connection with the upper filter cup, and the lower part is provided with a middle thread sealing sleeve. The internal thread provided on the middle thread sealing sleeve is connected to the external thread provided on the lower groove filter screen, and the connection is sealed.

[0018] The lower filter screen is set inside the threaded sealing sleeve and directly above the groove on the upper surface of the lower grooved filter screen. The threaded sealing sleeve and the lower grooved filter screen simultaneously hold and flatten the lower filter screen, forming a second layer of microplastic filtration structure.

[0019] The lower filter screen is a nylon mesh screen with a mesh diameter of less than 20 micrometers (the specific mesh diameter can be selected according to the detection quality requirements).

[0020] The vacuum pump is connected to the suction pipe of the filter bottle via a flexible hose; the flexible hose is also equipped with a switch, which is located between the suction pipe of the filter bottle and the filter bottle, and is used to control the opening and closing of the pipeline between the vacuum pump and the filter bottle.

[0021] The drain pipe is equipped with a switch to control the drainage and sealing status of the filter bottle.

[0022] The lower end face of the funnel tube is lower than the lower end face of the suction tube, and the end cross-section of the funnel tube is a tangential surface, so that the filtered water enters the bottom of the filter bottle without blocking the suction tube, ensuring the smooth operation of the vacuum pump after filtration.

[0023] The upper threaded sealing sleeve and the upper filter cup are integrally formed. On the outer side of the upper threaded sealing sleeve, there are also multiple vertical lines to increase the surface friction.

[0024] The central threaded sealing sleeve and the central filter cup are integrally formed. On the outer surface of the central threaded sealing sleeve, there are also multiple vertical lines to increase surface friction.

[0025] The outer surfaces of the upper filter cup, the middle filter cup, and the filter cup base funnel are flush. The upper threaded sealing sleeve of the upper filter cup is threadedly connected to the upper grooved filter screen of the middle filter cup, and the middle threaded sealing sleeve of the middle filter cup is threadedly connected to the lower grooved filter screen of the filter cup base funnel. After the two threads are tightened, the gaps at each connection of the microplastic double-layer filter structure are sealed.

[0026] Compared with the prior art, the beneficial effects of this utility model are:

[0027] 1. The portable microplastic filtration device for surface water samples provided by this utility model simplifies the overall structure and adopts a detachable connection method through the improved design of the structure and cooperation relationship of multiple components. It is small in size and each component is easy to assemble and disassemble quickly and is portable, so as to meet the requirements of on-site, daily, batch and diversified (meeting multiple detection qualities and different collection scales) filtration and collection of microplastics in surface water. Moreover, it is easy to operate, has a short filtration time and low cost.

[0028] 2. The portable surface water sample microplastic filtration device provided by this utility model, by setting up components such as an upper filter cup, a middle filter cup, a filter cup base funnel, a filter bottle and a vacuum pump, etc., the components work together to enable it to quickly filter microplastics in surface water samples while meeting the detection limits of different instruments. It optimizes the pretreatment steps of surface water microplastic samples, reduces labor intensity and improves the efficiency of filtration operation.

[0029] 3. The portable microplastic filtration device for surface water samples provided by this utility model uses an upper and lower filter screen, the size of which can be adjusted according to actual testing needs. After filtration, the particles on the nylon screen can be collected for subsequent digestion, flotation and other steps, eliminating the traditional membrane filtration operation. The filter screen can be reused after cleaning. It is easy to operate, has a short filtration time and low cost, and greatly saves the cost of on-site testing and pretreatment of batch water samples. Attached Figure Description

[0030] Figure 1 This is a three-dimensional overall structural diagram of the microplastic filtration device for surface water according to an embodiment of the present invention.

[0031] Figure 2 This invention relates to a microplastic filtration device for surface water, as described in an embodiment of the present invention. Figure 1 Schematic diagram of the assembly structure of the middle filter cup

[0032] In the diagram: 1. Upper filter cup; 2. Upper threaded sealing sleeve; 3. Upper filter screen; 4. Upper grooved filter screen; 5. Middle filter cup; 6. Middle threaded sealing sleeve; 7. Lower filter screen; 8. Lower grooved filter screen; 9. Filter cup base funnel; 10. Funnel tube; 11. Bottle neck plug; 12. Filter bottle; 13. Drain pipe; 14. Suction pipe; 15. Flexible hose; 16. Vacuum pump. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0034] Example 1

[0035] The portable microplastic filtration device for surface water samples provided by this utility model focuses on improving the structure and size of the device to meet the daily, batch, and diversified needs for sampling, filtering, collecting, and detecting microplastics in surface water. This makes it portable, fast, and easy to operate.

[0036] See appendix Figure 1-2 The portable microplastic filtration device for surface water samples provided by this utility model includes a detachably connected microplastic double-layer filtration structure, a filter bottle 12, and a vacuum pump 16; the three are detachably connected as a whole; they are stored separately during transportation and reassembled and used at the water sample collection site.

[0037] In this embodiment, the filter bottle 12 is a transparent plastic or glass bottle with a capacity of more than 5L, which can filter a 5L water sample at one time, thereby improving the speed of filtering and collecting microplastics in the water sample.

[0038] The filter bottle 12 is provided with an air extraction pipe 14 and a drain pipe 13 on its side wall; a bottleneck plug 11 is provided in the internal channel at the bottleneck of the filter bottle 12 to seal the bottleneck.

[0039] The vacuum pump 16 is connected to the suction pipe 14 of the filter bottle 12 via a hose 15;

[0040] The microplastic double-layer filtration structure comprises, from top to bottom, stacked and connected internally: upper filter cup 1, upper filter screen 3, middle filter cup 5, lower filter screen 7, and filter cup base funnel 9;

[0041] Both the upper filter cup 1 and the middle filter cup 5 are cylindrical containers with open openings at the top and bottom.

[0042] The upper opening of the middle filter cup 5 is provided with an upper grooved filter screen 4 to support the upper filter screen 3;

[0043] The upper opening of the filter cup base funnel 9 is provided with a lower groove filter screen 8 and the bottom is provided with a funnel tube 10; the lower groove filter screen 8 supports the lower filter screen 7, and the funnel tube 10 passes through the neck stopper 11 to reach the hollow position inside the filter bottle 12.

[0044] The upper filter cup 1 has an open opening at the top and an upper threaded sealing sleeve 2 at the bottom. The internal thread on the upper threaded sealing sleeve 2 is connected to the external thread on the upper grooved filter screen 4, and the connection is sealed.

[0045] The upper filter 3 is set inside the upper threaded sealing sleeve 2 and directly above the groove on the upper end face of the upper grooved filter 4. The upper threaded sealing sleeve 2 and the upper grooved filter 4 simultaneously hold the lower filter 3 in place and flatten it, forming the first layer of microplastic filtration structure.

[0046] The upper filter 3 is a nylon mesh screen with a mesh diameter of 5 mm (the specific type can be selected according to the testing quality requirements).

[0047] The upper part of the middle filter cup 5 is provided with an open opening that connects to the upper filter cup 1, and the lower part is provided with a middle thread sealing sleeve 6. The internal thread provided on the middle thread sealing sleeve 6 is connected to the external thread provided on the lower groove filter screen 8, and the connection is sealed.

[0048] The lower filter 7 is located inside the threaded sealing sleeve 6 and directly above the groove on the upper surface of the lower grooved filter 8. The threaded sealing sleeve 6 and the lower grooved filter 8 simultaneously hold the lower filter 7 in place and flatten it, forming a second layer of microplastic filtration structure.

[0049] The upper grooved filter screen 4 and the lower grooved filter screen 8 both have downward-sloping grooves on their upper surfaces, which provide support and elastic deformation space when the filter screens are deformed by water pressure during the filtration process.

[0050] The lower filter 7 is a nylon mesh screen with a mesh diameter of less than 20 micrometers (the specific type can be selected according to the testing quality requirements).

[0051] The vacuum pump is connected to the suction pipe 14 of the filter bottle 12 via a hose 15; the hose 15 is also equipped with a switch, which is located between the suction pipe 14 of the filter bottle 12 and the filter bottle, and is used to control the opening and closing of the pipeline between the vacuum pump and the filter bottle.

[0052] The drain pipe 13 is equipped with a switch to control the drainage and sealing state of the filter bottle 12.

[0053] The lower end face of the funnel tube is lower than the lower end face of the suction tube, and the end cross-section of the funnel tube is a tangential surface, so that the filtered water enters the bottom of the filter bottle 12 without blocking the suction tube, thus ensuring the smooth operation of the vacuum pump after filtration.

[0054] The upper threaded sealing sleeve 2 and the upper filter cup 1 are integrally formed. On the outer side of the upper threaded sealing sleeve 2, there are also multiple vertical lines to increase the surface friction.

[0055] The threaded sealing sleeve 6 and the filter cup 5 are integrally formed. On the outer surface of the threaded sealing sleeve 6, there are also multiple vertical lines to increase the surface friction.

[0056] The outer surfaces of the upper filter cup 1, the middle filter cup 5, and the filter cup base funnel 9 are flush; the upper threaded sealing sleeve 2 of the upper filter cup 1 is threadedly connected to the upper grooved filter screen 4 of the middle filter cup 5, and the middle threaded sealing sleeve 6 of the middle filter cup 5 is threadedly connected to the lower grooved filter screen 8 of the filter cup base funnel 9. After the two threads are tightened, the gaps at each connection of the microplastic double-layer filter structure are sealed.

[0057] A suction pipe 14 is installed at a high position on the side wall of the filter bottle 12, and a drain pipe 13 is installed at a low position; a bottleneck plug 11 is installed in the internal channel of the bottleneck of the filter bottle 12 to seal the bottleneck, so as to ensure that the interior of the filter bottle 12 does not leak air when vacuuming.

[0058] The vacuum pump 16 is connected to the suction pipe 14 of the filter bottle 12 via the hose 15. It is used to draw a vacuum in the filter bottle 12 when filtering water samples, thereby speeding up the filtration speed and preventing insufficient pressure under natural atmospheric pressure from particles deposited on the filter screen that could block the continuous passage of water samples.

[0059] The microplastic double-layer filtration structure includes the following components stacked and connected from top to bottom and internally interconnected: upper filter cup 1, upper filter screen 3, upper grooved filter screen 4, middle filter cup 5, lower filter screen 7, lower grooved filter screen 8, and filter cup base funnel 9.

[0060] The upper part of the upper filter cup 1 is an open opening, and the bottom of the filter cup base funnel 9 is provided with a funnel tube 10. The funnel tube 10 passes through the neck plug 11 to reach the hollow position inside the filter bottle 12. During filtration, the water in the water sample flows into the interior of the filter bottle 12 until all the water is filtered and then discharged.

[0061] Both the upper filter cup 1 and the middle filter cup 5 are hollow, cylindrical transparent containers with vertical openings at the top and bottom. The upper and lower parts of the upper filter cup 1 are open openings. The lower part of the upper filter cup 1 is also provided with an upper threaded sealing sleeve 2. The internal thread on the upper threaded sealing sleeve 2 is connected to the external thread on the upper grooved filter screen 4, and the connection is sealed. The upper threaded sealing sleeve 2 and the upper filter cup 1 are integrally manufactured. On the outer side of the upper threaded sealing sleeve 2, there are multiple vertical lines to increase the surface friction and facilitate manual rotation, making it convenient for manual installation or disassembly at the sampling site.

[0062] The upper filter 3 is set inside the upper threaded sealing sleeve 2 and directly above the groove on the upper end face of the upper grooved filter 4. The upper threaded sealing sleeve 2 and the upper grooved filter 4 simultaneously hold the lower filter 3 in place and flatten it, forming the first layer of microplastic filtration structure.

[0063] The upper filter 3 is a nylon mesh screen with a mesh diameter of 1 to 5 mm (the specific selection can be made according to the testing quality requirements).

[0064] The upper part of the middle filter cup 5 is provided with an open opening (both have the same diameter) for connection with the upper filter cup 1. The upper grooved filter screen 4 (coarse mesh, with a mesh diameter of 5 mm or more) is provided in the opening to support the upper filter screen 3. The lower part is provided with a central threaded sealing sleeve 6. The internal thread on the central threaded sealing sleeve 6 is connected to the external thread on the lower grooved filter screen 8 and seals the connection. The central threaded sealing sleeve 6 and the middle filter cup 5 are also integrally manufactured (e.g., injection molded). On the outer surface of the central threaded sealing sleeve 6, there are also multiple vertical lines to increase surface friction, facilitate manual rotation, and make it convenient for manual installation or disassembly at the sampling site.

[0065] The lower filter 7 is set inside the threaded sealing sleeve 6 and directly above the groove on the upper surface of the lower groove filter 8. The threaded sealing sleeve 6 and the lower groove filter 8 simultaneously hold the lower filter 7 in place and flatten it to form a second layer of microplastic filtration structure.

[0066] The lower filter 7 is a nylon mesh screen with a mesh diameter of 10-20 micrometers (the specific type can be selected according to the detection quality requirements).

[0067] The suction pipe 14 is located on the upper part of the side wall of the filter bottle 12; the drain pipe is located on the lower part of the side wall of the filter bottle 12.

[0068] The vacuum pump is connected to the suction pipe 14 of the filter bottle 12 via a hose 15; the hose 15 is also equipped with a switch, which is located between the suction pipe 14 of the filter bottle 12 and the filter bottle, and is used to control the opening and closing of the pipeline between the vacuum pump and the filter bottle.

[0069] The drain pipe 13 is equipped with a switch to control the flow of water from the filter bottle 12 and the sealing state inside the filter bottle 12.

[0070] The lower end face of the funnel tube is lower than the lower end face of the suction tube, and the end cross-section of the funnel tube is a tangential surface, so that the filtered water enters the bottom of the filter bottle 12 without blocking the suction tube, thus ensuring the smooth operation of the vacuum pump after filtration.

[0071] Example 2

[0072] The portable microplastic filtration device for surface water samples provided in this embodiment is a further optimization based on Embodiment 1. The difference between it and Embodiment 1 is that:

[0073] The upper filter cup 1 has an open upper opening and an upper threaded sealing sleeve 2 on the outside of the lower opening. A nylon upper filter screen 3 is installed inside the upper threaded sealing sleeve 2.

[0074] The middle filter cup 5 has an upper grooved filter screen connected to the upper filter screen 3 in the upper opening, and a middle threaded sealing sleeve 6 is set below it. A lower filter screen 7 made of nylon is set inside the middle threaded sealing sleeve 6.

[0075] The filter cup base funnel 9 has a grooved filter screen 8 in its upper opening, which supports the lower filter screen 7; a sealed funnel is provided below, and the water sample passing through the lower filter screen is finally collected directly by the filter bottle 12 through the funnel tube 10.

[0076] After installation, the upper filter screen 3 is fixedly installed between the upper filter cup 1 and the middle filter cup 5. The upper filter screen 3 is a nylon screen with a mesh diameter of 5 mm. The lower filter screen 7 is fixedly installed between the middle filter cup 5 and the filter cup base funnel 9. The lower filter screen 7 is also a nylon screen with a mesh diameter of 10 micrometers.

[0077] The funnel tube 10 is set at the bottom of the filter cup base funnel 9 and is integrally formed with the filter cup base funnel;

[0078] A filter bottle 12 is placed directly below the funnel 9 of the filter cup base;

[0079] The connection between the upper filter cup 1 and the middle filter cup 5, and between the middle filter cup 5 and the filter cup base funnel 9, are all threaded connections. After the connection is completed, the upper filter screen 3 and the lower filter screen 7 are located inside the sealed structure, and the two threaded sealing sleeves are tightly connected to the upper filter screen 3 and the lower filter screen 7 respectively.

[0080] The upper filter 3 is specifically a perforated mesh structure, with its outer diameter smaller than the inner diameter of the upper grooved filter 4. The mesh diameter of the upper filter 3 is 5 mm to meet the size requirements for the first-stage filtration of microplastics.

[0081] The lower filter 7 is also a perforated mesh structure, and its outer diameter is smaller than the inner diameter of the lower groove filter 8. The surface size of the lower filter can be selected to install nylon screens such as 10 micrometers or 20 micrometers to meet the requirements of the instrument detection line.

[0082] The filter bottle 12 is equipped with:

[0083] A neck stopper is disposed at the neck of the filter bottle, specifically a silicone stopper with a through hole.

[0084] The drain pipe is specifically installed on the side wall of the lower part of the filter bottle, and a threaded sealing sleeve is installed inside the drain pipe to fix it to the side wall of the filter bottle.

[0085] The suction pipe is specifically installed on the upper side wall of the filter bottle, and the inside of the suction pipe is set into a flared opening for connection with a flexible hose;

[0086] A flexible tube is provided on the outside of the filter bottle, and the end of the connecting tube is connected to a vacuum pump;

[0087] In this embodiment, the bottleneck plug is a perforated silicone plug made of silicone material, and its cross-section is trapezoidal, which matches the outer dimensions of the bottleneck plug opening.

[0088] The operating steps of this utility model are as follows:

[0089] 1. Assembly of the filter device:

[0090] The individual components were transported to the sampling site and then manually assembled.

[0091] First, select the upper filter screen 3 and the lower filter screen 7 with suitable mesh diameters, and place them on the upper grooved filter screen 4 and the lower grooved filter screen 8 respectively. Then, connect the upper filter cup 1, the middle filter cup 5, and the filter cup base funnel 9 in sequence, and tighten the threads to obtain an internally sealed microplastic double-layer filtration structure.

[0092] Place the neck plug 11 at the neck of the filter bottle 12 and seal the opening at the neck.

[0093] Then insert the funnel tube 10 into the neck stopper 11, with the bottom end reaching the lower part of the filter bottle 12;

[0094] The extraction port of the vacuum pump 16 is connected to the inside of the filter bottle 12 via the hose 15 and the suction pipe 14.

[0095] Finally, turn off the drain pipe switch 13 to seal the inside of the filter bottle 12 and the microplastic double-layer filter structure.

[0096] 2. Operation of the filtration device:

[0097] When using this utility model, first check whether the funnel tube 10 and the neck plug 11 are sealed, whether the drain pipe 13 is closed, and whether the switch on the hose 15 is open.

[0098] After verifying that everything is correct, turn on the power and switch on vacuum pump 16. This generates and maintains negative pressure inside filter bottle 12 and the microplastic double-layer filtration structure. Continuously pour 5L of water sample to be filtered from the field into the upper filter cup 1. The water sample passes through the upper filter screen 3 and the lower filter screen 7 in sequence, entering filter bottle 12 one after another until all the water sample is filtered, completing the filtration operation. Turn off the power to vacuum pump 16 and turn on the drain pipe 13 to drain the water. Collect the particulate matter deposited on the lower filter screen 7 for subsequent detection steps and processes such as microplastic digestion and flotation, completing the filtration and collection of a single water sample.

[0099] 3. Disassembly after completion

[0100] After repeatedly filtering water samples and completing all filtration tasks at a single work site, the entire device is completely disassembled, and each part is stored independently in a storage container (such as a toolbox). It is then carried to the next work site, and the aforementioned steps are repeated to carry out water sample filtration work at the new sampling point.

[0101] The above-described embodiments of this utility model focus on improving the design of the structure and the cooperation relationship of multiple components, making them easy to assemble and disassemble quickly and portable, so as to meet the requirements of on-site, daily, batch and diversified (meeting multiple detection qualities and different collection scales) filtration and collection of microplastics in surface water. Moreover, it is easy to operate, has a short filtration time and low cost, and eliminates the need to bring water samples back to the laboratory for filtration, which can significantly save time and labor costs for sample transportation and microplastic collection.

[0102] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0103] Although the basic technical content of the present invention has been shown and described in the above embodiments, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A portable device for filtering microplastics from surface water samples, characterized in that, It includes a detachable microplastic double-layer filter structure, a filter bottle (12), and a vacuum pump (16). The filter bottle (12) is provided with an air extraction pipe (14) and a drain pipe (13) on its side wall; a bottleneck plug (11) is provided in the internal channel at the bottleneck of the filter bottle (12) to seal the bottleneck. The vacuum pump (16) is connected to the suction pipe (14) of the filter bottle (12) via a hose (15); The microplastic double-layer filter structure includes the following components stacked and connected from top to bottom and internally interconnected: upper filter cup (1), upper filter screen (3), middle filter cup (5), lower filter screen (7), and filter cup base funnel (9). The upper filter cup (1) and the middle filter cup (5) are both cylindrical containers with open openings at the top and bottom. The upper opening of the middle filter cup (5) is provided with an upper groove filter screen (4) to support the upper filter screen (3). The upper opening of the funnel (9) of the filter cup base is provided with a grooved filter screen (8) and the bottom is provided with a funnel tube (10); the grooved filter screen (8) supports the lower filter screen (7) and the funnel tube (10) passes through the neck stopper (11) to reach the hollow position inside the filter bottle (12).

2. The portable surface water sample microplastic filtration device according to claim 1, characterized in that: The upper filter cup (1) has an open opening at the top and an upper threaded sealing sleeve (2) at the bottom. The internal thread on the upper threaded sealing sleeve (2) is connected to the external thread on the upper grooved filter screen (4) and seals the connection. The upper filter (3) is set inside the upper threaded sealing sleeve (2) and directly above the groove on the upper end face of the upper grooved filter (4). The upper threaded sealing sleeve (2) and the upper grooved filter (4) simultaneously hold and flatten the lower filter (7) to form the first layer of microplastic filter structure.

3. The portable surface water sample microplastic filtration device according to claim 2, characterized in that: The upper filter screen (3) is a nylon mesh screen with a mesh diameter of 5 mm.

4. The portable surface water sample microplastic filtration device according to claim 2, characterized in that: The middle filter cup (5) is a cylindrical container with open openings at both the top and bottom. The upper opening is provided with an upper grooved filter screen (4), which is connected to the open opening at the bottom of the upper filter cup (1). The lower opening is also provided with a lower threaded sealing sleeve (6), and the internal thread on the middle threaded sealing sleeve (6) is connected to the external thread on the lower grooved filter screen (8), thus sealing the connection. The lower filter (7) is set inside the threaded sealing sleeve (6) and directly above the groove on the upper surface of the lower groove filter (8). The threaded sealing sleeve (6) and the lower groove filter (8) simultaneously hold the lower filter (7) in place and flatten it to form a second layer of microplastic filtration structure.

5. The portable surface water sample microplastic filtration device according to claim 4, characterized in that: The lower filter (7) is a nylon mesh screen with a mesh diameter of less than 20 micrometers.

6. The portable surface water sample filtration device according to claim 1, characterized in that: The suction pipe (14) is located on the upper part of the side wall of the filter bottle (12); the drain pipe (13) is located on the lower part of the side wall of the filter bottle (12). The vacuum pump (16) is connected to the suction pipe (14) of the filter bottle (12) via a hose (15); The hose (15) is also equipped with a switch, which is located between the suction pipe (14) of the filter bottle (12) and the filter bottle (12).

7. The portable surface water sample microplastic filtration device according to claim 1, characterized in that: The drain pipe (13) is equipped with a switch.

8. The portable surface water sample filtration device according to claim 1, characterized in that: The lower end face of the funnel tube (10) is lower than the lower end face of the suction tube (14), and the end cross-section of the funnel tube (10) is a tangent.

9. The portable surface water sample microplastic filtration device according to claim 4, characterized in that: The upper threaded sealing sleeve (2) and the upper filter cup (1) are integrally formed. On the outer side of the upper threaded sealing sleeve (2), there are also multiple vertical lines to increase the surface friction. The central threaded sealing sleeve (6) and the central filter cup (5) are integrally formed. On the outer side of the central threaded sealing sleeve (6), there are also multiple vertical lines to increase the surface friction.

10. The portable surface water sample filtration device according to claim 1, characterized in that: The upper filter cup (1), the middle filter cup (5), and the outer surface of the filter cup base funnel (9) are flush; the upper threaded sealing sleeve (2) of the upper filter cup (1) is threadedly connected to the upper grooved filter screen (4) of the middle filter cup (5), and the middle threaded sealing sleeve (6) of the middle filter cup (5) is threadedly connected to the lower grooved filter screen (8) of the filter cup base funnel (9). After the two threads are tightened, the gaps at each connection of the microplastic double-layer filter structure are sealed.

Images