An integrated device for simultaneously collecting and separating microplastics in a surface environment

Abstract

The utility model relates to micro plastic collecting technical field, concretely relates to a surface environment micro plastic synchronous collection separation integrated equipment. The equipment includes gas collection device, circulating air pump, circulating water pump, cooling ring and flotation tower, the upper portion of flotation tower is provided with cooling ring, the bottom is provided with corundum aeration device, one end of circulating air pump is connected through pipeline and two groups of air inlet of gas collection device, the other end is connected through pipeline and the top export of flotation tower, one end of circulating water pump is connected through pipeline and circulating water outlet, the other end is connected through Y type pipeline and corundum aeration device, gas collection device's air outlet, the equipment needs to ensure that it is in the closed circulation process when working. The equipment can collect the micro plastic of various particle sizes and other impurities that can diffuse through natural conditions in the surface environment, and enrich the micro plastic synchronously, separate the impurities, so as to realize the purpose of efficient collection of micro plastic sample.

Description

Technical Field

[0001] This utility model relates to the field of microplastic collection technology, specifically to an integrated device for the synchronous collection and separation of microplastics in the surface environment. Background Technology

[0002] Microplastics are a new type of pollutant, found globally, and their pollution has garnered widespread attention worldwide. Microplastic particles in the Earth's surface environment range in size from a few micrometers to a few millimeters, making them easily ingested by animals and entering the food chain, thus impacting the health of the entire ecosystem. Studies have found that marine life such as fish, shellfish, and birds frequently ingest microplastics, leading to damage to their digestive systems and even death. Furthermore, microplastics may carry toxic chemicals, which, once ingested, can trigger a range of health problems. In humans, microplastics have been detected in blood, breast milk, lungs, heart, testes, and even the placenta.

[0003] Microplastics in urban ground environments are diverse, primarily including: tire wear particles, industrial raw material particles released into the ground environment during transportation or production, film fragments from the tearing and decomposition of plastic bags and packaging materials, foam fragments from the breakage of polystyrene foam (such as foam cups and packaging materials), and other types of microplastics, including fibers, fragments, and particles, which may originate from various plastic waste and recyclables, such as plastic bottles, plastic bags, and plastic tableware. These microplastics are widely distributed in the ground environment and can be spread through water, atmosphere, and soil, posing potential risks to ecosystems and human health. Due to their lightness and small size, microplastic particles in urban ground environments can move freely in the three-phase environment. Microplastic particles with a diameter less than 150 μm can be carried by wind to other areas; some remain suspended in the atmosphere and enter and accumulate in organisms through respiration and ingestion; others enter water bodies or soil through wet and dry deposition. Larger microplastic particles are carried by rainwater runoff into rivers and lakes, eventually flowing into the ocean. Over time, these microplastics will gradually age and break down due to natural processes such as wind and sun exposure, oxidation and wear, and microbial degradation. In addition, some microplastics may enter the soil and seep into groundwater with rainfall, or be migrated through the activities of plants and animals.

[0004] Currently, research on microplastics in the field of environmental monitoring focuses more on identification and monitoring techniques, such as advanced technologies like microscopy, spectroscopic analysis, solvent extraction and concentration, and Py-GCMS testing, as well as cutting-edge equipment like microscopic infrared, laser infrared, pyrolysis-gas chromatography-mass spectrometry, Raman spectroscopy, and scanning electron microscopy. However, there is a lack of corresponding specialized techniques for environmental collection. For example, in collecting microplastics from environmental surfaces, traditional methods such as brushes and vacuum cleaners are still used. These methods have significant drawbacks in terms of sample collection quality control: firstly, they cannot ensure that all samples within the sampling area are collected; secondly, brushes and vacuum cleaners may trap some microplastic particles during sampling or release microplastic particles that are not part of the environmental background; thirdly, the collected samples may be degraded or contaminated; and fourthly, they are greatly affected by human factors, etc. Sample collection is the foundation and key to environmental monitoring, directly affecting the accuracy and reliability of monitoring data, and consequently influencing environmental management decisions and effectiveness. During sample collection, strict adherence to relevant standards and specifications is essential to ensure the representativeness, completeness, and timeliness of the collected samples. Currently, there are no standards or methods for collecting microplastics from environmental surfaces, highlighting the urgent need for an effective, quantitative, and highly automated collection method for microplastic monitoring. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. This device can collect microplastics of various particle sizes and other impurities that can diffuse through natural conditions in the surface environment, and simultaneously enrich the microplastics and separate the impurities, thereby achieving the goal of efficient collection of microplastic samples.

[0006] Therefore, the present invention provides the following technical solution:

[0007] In one aspect, the present invention provides an integrated device for the synchronous collection and separation of microplastics in the surface environment in an optional embodiment, including a gas collection device, a circulating air pump, a circulating water pump, a cooling ring, and a flotation tower.

[0008] The gas collection device includes a gas collection hood, two sets of air inlets and air outlets. The gas collection hood includes a support part and a functional part. The support part is cylindrical in shape, and the functional part is conical in shape. The top surface of the support part and the bottom surface of the functional part are closely fitted together. The air outlet is opened at the apex of the functional part, and the two sets of air inlets are symmetrically opened on both sides of the surface of the functional part.

[0009] The flotation tower has conical ends and a cylindrical middle section. Outlets are located at the top and bottom of the tower. A check valve is installed at the top outlet to prevent gas backflow. The bottom outlet is connected to a vent pipe. A corundum aeration device is installed at the bottom of the tower. A cooling ring is located at the top of the tower to condense water vapor in the air above. A circulating water outlet is located at the top between the cooling ring and the corundum aeration device. A sample collection pipe is located in the middle between the circulating water outlet and the corundum aeration device. One end of the corundum aeration device is connected to a feed pipe.

[0010] One end of the circulating air pump is connected to the two sets of air inlets of the gas collection device through a pipeline, and the other end is connected to the top outlet of the flotation tower through a pipeline.

[0011] One end of the circulating water pump is connected to the circulating water outlet via a pipeline, and the other end is connected to the other end of the feed pipe and the air outlet of the gas collection device via a Y-shaped pipeline.

[0012] In the utility model, the gas collection hood is made of stainless steel.

[0013] Preferably, the flotation tower is filled with flotation liquid; when the integrated device for simultaneous collection and separation of microplastics in the surface environment is not in operation, the settling level of the flotation liquid is 30 mm higher than the sample collection tube and lower than the height of the circulating water outlet; when the integrated device for simultaneous collection and separation of microplastics in the surface environment is in operation, the working level of the flotation liquid is at least 10 mm higher than the circulating water outlet. The flotation liquid is a mixture of rapeseed oil and saturated potassium formate solution; in the mixture of rapeseed oil and saturated potassium formate solution, the volume ratio of rapeseed oil to saturated potassium formate solution is 1:6; the physical properties of the rapeseed oil are: light yellow transparent liquid, melting point about -9℃, and density of 0.915-0.920 g / cm³. 3 (25℃), refractive index 1.47 (20℃), insoluble in water, readily soluble in organic solvents such as ether and chloroform. Chemical properties: contains unsaturated fatty acids (such as linoleic acid and erucic acid), phospholipids, and trace amounts of vitamin E. The Macklin purity of the potassium formate is ≥99.5%.

[0014] Preferably, the bottom diameter of the functional part of the gas collecting hood is the same as the diameter of the supporting part of the gas collecting hood; the ratio of the bottom diameter of the functional part of the gas collecting hood to its cone height is 10:1, and the ratio of the bottom diameter of the supporting part of the gas collecting hood to its column height is 10:1; preferably, the bottom diameter of the functional part of the gas collecting hood is 200mm, the cone height is 20mm, the bottom diameter of the supporting part of the gas collecting hood is 200mm, and the column height is 20mm. The diameter of the central cylindrical shape of the flotation tower is 60mm, and the column height is 1000mm; the bottom diameter of the conical shapes at both ends of the flotation tower is 60mm, and the cone height is 30mm. The lowest point of the cooling ring is located at 700mm of the column height of the central cylindrical shape of the flotation tower; the circulating water outlet is located at 600mm of the column height of the central cylindrical shape of the flotation tower; the sample collection tube is located at 500mm of the column height of the central cylindrical shape of the flotation tower.

[0015] Furthermore, both the support portion and the functional portion have cavities, and the shapes of the support portion and the functional portion are the same. The cavities in the support portion and the functional portion form a through structure, and the diameter of the cavity in the support portion and the bottom diameter of the cavity in the functional portion are the same. The air outlet is located at the apex of the functional portion and forms a through structure with the cavity in the functional portion. Two sets of air inlets are symmetrically located on both sides of the surface of the functional portion and form a through structure with the cavity in the functional portion. The vertical distance between the two sets of air inlets and the bottom surface of the functional portion is half the cone height of the functional portion. The ratio of the bottom diameter of the functional portion to its cone height is 9-11:1, the ratio of the bottom diameter of the support portion to its column height is 9-11:1, the angle between the opening direction of the two sets of air inlets and the horizontal direction is 30°, and they are rotated 45° around the longitudinal axis.

[0016] Preferably, the cooling ring contains a polymeric refrigerant of polyacrylic acid polyol or a cooling solution; it is used to condense water vapor in the air above the flotation tower. In use, the pre-cooled cooling ring is placed at the top of the flotation tower to maintain the temperature at the top of the tower at 0-10℃, promoting the condensation of water vapor in the air flowing out of the flotation tower, thereby achieving the purpose of keeping the circulating gas inside the device dry. The flotation tower is made of plexiglass for easy observation of the flotation separation process; the pipes used in the integrated surface environment microplastic collection and separation equipment are all made of silicone. The corundum aeration device is a sphere with a diameter of 50mm, and its surface is covered with pores with a diameter of 5mm, which allows for thorough mixing of air, microplastics, and flotation liquid; a check valve is installed at the middle of the connection between the air outlet of the gas collection device and the Y-shaped pipe to prevent liquid from entering the pipe.

[0017] Furthermore, the cooling ring is a semi-circular cylinder with an inner diameter of 6.5cm, an outer diameter of 8.5cm, and a height of 30cm. The cylindrical part has a flange on its edge. In use, the cooling ring, which has been pre-frozen or refrigerated in a refrigerator, is placed on the top of the flotation tower to keep the temperature at the top of the flotation tower at 0~10℃. This causes the water vapor in the air flowing out of the flotation tower to condense, thereby achieving the purpose of keeping the circulating gas in the device dry.

[0018] Furthermore, the integrated equipment for simultaneous collection and separation of microplastics in the surface environment must be operated in a closed-loop process.

[0019] Preferably, the jet aeration velocity of the corundum aeration device is 15.5 m / s; the flow rate of the circulating water pump is 3-8 L / min, and the flow rate of the circulating air pump is 290-420 L / min; the flotation working time is 30 s, and the settling time is 3 min. The circulating air pump is model 2755 with a capacity of 100-500 L / min, and the circulating water pump is model XYH-910 with a capacity of 0-350 L / h.

[0020] Compared with the prior art, this utility model has one of the following beneficial effects:

[0021] 1. The integrated device for simultaneous collection and separation of microplastics in the surface environment provided by this utility model can collect microplastics of various particle sizes and other impurities that can diffuse through natural conditions in the surface environment, and simultaneously enrich the microplastics and separate the impurities, thereby achieving the purpose of efficient collection of microplastic samples.

[0022] 2. The method for simultaneous collection and separation of microplastics from the surface environment provided by this utility model can complete the collection and separation of microplastics from urban surfaces in a short period of time. The entire sampling and flotation process is isolated from the regional environment, and water and air are recycled, effectively preventing the introduction of microplastics from outside the sampling area. Jet aeration technology enhances the gas-liquid dispersion effect and can effectively shorten the flotation time. This sampling method can accurately collect microplastic samples within a unit area, providing technical support for environmental surveys and pollution status assessments. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the integrated device for synchronous collection and separation of microplastics in the ground environment according to Embodiment 1 of this utility model;

[0025] Figure 2 This is a schematic diagram of the flotation tower structure of the integrated device for synchronous collection and separation of microplastics in the surface environment according to Embodiment 1 of this utility model;

[0026] Figure 3 This is a top view of the corundum aeration device of the integrated equipment for synchronous collection and separation of microplastics in the ground environment according to Embodiment 1 of this utility model.

[0027] Figure 4 This is a front view of the gas collection device of the integrated device for synchronous collection and separation of microplastics in the ground environment according to Embodiment 1 of this utility model;

[0028] Figure 5 This is a top view of the gas collection device of the integrated device for synchronous collection and separation of microplastics in the ground environment according to Embodiment 1 of this utility model;

[0029] Figure 6 The collection efficiency of the integrated device for synchronous collection and separation of microplastics in the surface environment in Embodiment 1 of this utility model at different times;

[0030] Figure 7 The flotation separation efficiency of the integrated device for synchronous collection and separation of microplastics in the surface environment in Embodiment 1 of this utility model at different times;

[0031] Figure 8 This is a schematic diagram showing the completeness of the automatic collection and separation of microplastic samples by the integrated device for synchronous collection and separation of microplastics in the surface environment according to Embodiment 1 of this utility model;

[0032] Figure 9 The separation efficiency of the integrated device for synchronous collection and separation of microplastics in the ground environment in Embodiment 1 and Comparative Examples 1-14 of this utility model;

[0033] Figure 10 The separation efficiency of the integrated device for synchronous collection and separation of microplastics in the surface environment of this utility model in Embodiment 1 and Comparative Examples 7-14 at different times;

[0034] Among them, 1-Gas collection hood, 2-Flotation tower, 3-Cooling ring, 4-Circulating water pump, 5-Circulating air pump, 6-Check valve, 7-Corundum aeration device, 8-Air outlet, 9-Drain pipe, 11-Air inlet, 12-Feed pipe, 13-Circulating water outlet, 15-Sample collection pipe. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.

[0036] Example 1

[0037] See Figure 1 This embodiment provides an integrated device for simultaneous collection and separation of microplastics in the surface environment, including a gas collection device, a circulating air pump 5, a circulating water pump 4, a cooling ring 3, and a flotation tower 2;

[0038] See Figures 4-5 The gas collection device includes a gas collection hood 1, two sets of air inlets 11 and air outlets 8. The gas collection hood includes a support part and a functional part. The support part is cylindrical and the functional part is conical. The top surface of the support part and the bottom surface of the functional part are closely fitted, and the diameter of the support part and the bottom surface diameter of the functional part are the same. In this embodiment, the diameter of the support part and the bottom surface diameter of the functional part are both 200mm. The column height of the support part is 20mm and the cone height of the functional part is 20mm.

[0039] Both the support section and the functional section have cavities, and the shapes of the support section and the functional section are the same. The cavities in the support section and the cavities in the functional section form a through structure, and the diameter of the cavity in the support section and the bottom diameter of the cavity in the functional section are the same.

[0040] The air outlet 8 is located at the apex of the functional part and forms a through structure with the cavity inside the functional part. In this embodiment, the air outlet 8 is cylindrical in shape and has a diameter of 20mm.

[0041] Two sets of air inlets 11 are symmetrically opened on both sides of the surface of the functional part and form a through structure with the cavity inside the functional part. The vertical distance between the two sets of air inlets 11 and the bottom surface of the functional part is half the cone height of the functional part. In this embodiment, the vertical distance between the two sets of air inlets 11 and the bottom surface of the functional part is 10mm. The shape of the two sets of air inlets 11 is cylindrical and the diameter is 20mm. The angle between the opening direction of the two sets of air inlets 11 and the horizontal direction is 30°, and they are rotated 45° around the longitudinal axis.

[0042] See Figure 2 Flotation tower 2 is made of plexiglass to facilitate observation of the flotation separation process. The middle section of flotation tower 2 is cylindrical with a diameter of 60mm and a height of 1000mm. Both ends are conical with a base diameter of 60mm and a cone height of 30mm. Outlets are located at the top and bottom of flotation tower 2. A check valve 6 is installed at the top outlet to prevent gas backflow, and the bottom outlet of flotation tower 2 is connected to an exhaust pipe 9.

[0043] A cooling ring 3 is installed at the top of the flotation tower 2 (in this embodiment, the lowest point of the cooling ring 3 is located at 400 mm above the column height of the flotation tower 2). The cooling ring 3 contains a polymeric refrigerant of polyacrylic acid polyol or a cooling solution to condense water vapor in the air above the flotation tower. In use, the cooling ring 3, which has been pre-frozen or refrigerated in a refrigerator, is placed at the top of the flotation tower to maintain the temperature at the top of the flotation tower 2 at 0-10°C, thereby promoting the condensation of water vapor in the air flowing out of the flotation tower 2 and achieving the purpose of keeping the circulating gas in the device dry. A corundum aeration device 7 is installed at the bottom of the flotation tower 2 (see...). Figure 3 The corundum aeration device 7 is a sphere with a diameter of 50 mm and its surface is covered with holes with a diameter of 5 mm, which can fully mix air, microplastics and flotation liquid. A circulation outlet 13 is provided at the upper part between the cooling ring 3 and the corundum aeration device 7 (in this embodiment, the circulation outlet is located at 600 mm of the height of the flotation column). A sample collection pipe 15 is provided in the middle between the circulation outlet 13 and the corundum aeration device 7 (in this embodiment, the sample collection pipe 15 is located at 500 mm of the height of the flotation column). One end of the corundum aeration device 7 is connected to the feed pipe 12, and the other end of the feed pipe 12 is connected to one end of the circulating water pump 4 and the air outlet 8 of the air collection device through a Y-shaped pipe.

[0044] One end of the circulating air pump 5 is connected to the two sets of air inlets 11 of the gas collection device through a pipeline, and the other end is connected to the top outlet of the flotation tower 2 through a pipeline. The other end of the circulating water pump 4 is connected to the circulating water outlet 13 through a pipeline.

[0045] Flotation column 2 contains flotation liquid. When the integrated device for simultaneous collection and separation of microplastics in the surface environment is not in operation, the level of the flotation liquid is higher than the height of the sample collection tube and lower than the height of the circulating water outlet 13. When the integrated device for simultaneous collection and separation of microplastics in the surface environment is in operation, the level of the flotation liquid is higher than the height of the circulating water outlet 13 and lower than the lowest point of the cooling ring 3. The flotation liquid is a mixture of rapeseed oil and saturated potassium formate solution; the volume ratio of rapeseed oil to saturated potassium formate solution in the mixture is 1:6. A check valve 6 is installed at the middle part of the connection between the gas outlet 8 of the gas collection device and the Y-shaped pipe to prevent liquid from entering the pipeline.

[0046] When the integrated equipment for simultaneous collection and separation of microplastics in the surface environment is in operation, it is necessary to ensure that it operates in a closed loop.

[0047] In this embodiment, the jet aeration velocity of the corundum aeration device 7 is 15.5 m / s, the circulating air pump 5 is model 2755 with a range of 100-500 L / min and a flow rate of 330 L / min, and the circulating water pump 4 is model XYH-910 with a range of 0-350 L / h and a flow rate of 5 L / min.

[0048] Comparative Example 1

[0049] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a saturated sodium chloride solution.

[0050] Comparative Example 2

[0051] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a saturated potassium formate solution.

[0052] Comparative Example 3

[0053] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation solution in the flotation tower is a saturated sodium iodide solution.

[0054] Comparative Example 4

[0055] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is castor oil.

[0056] Comparative Example 5

[0057] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is rapeseed oil.

[0058] Comparative Example 6

[0059] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is olive oil.

[0060] Comparative Example 7

[0061] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a mixture of castor oil and saturated sodium chloride solution, and the volume ratio of castor oil to saturated sodium chloride solution in the mixture is 1:6.

[0062] Comparative Example 8

[0063] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a mixture of castor oil and saturated sodium iodide solution, and the volume ratio of castor oil to saturated sodium iodide solution in the mixture is 1:6.

[0064] Comparative Example 9

[0065] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a mixture of rapeseed oil and saturated sodium chloride solution, and the volume ratio of rapeseed oil to saturated sodium chloride solution in the mixture is 1:6.

[0066] Comparative Example 10

[0067] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a mixture of rapeseed oil and saturated potassium formate solution, and the volume ratio of rapeseed oil to saturated potassium formate solution in the mixture is 1:6.

[0068] Comparative Example 11

[0069] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a mixture of rapeseed oil and saturated sodium iodide solution, and the volume ratio of rapeseed oil to saturated sodium iodide solution in the mixture is 1:6.

[0070] Comparative Example 12

[0071] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a mixture of olive oil and saturated sodium chloride solution, and the volume ratio of olive oil to saturated sodium chloride solution in the mixture is 1:6.

[0072] Comparative Example 13

[0073] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a mixture of olive oil and saturated potassium formate solution, and the volume ratio of olive oil to saturated potassium formate solution in the mixture is 1:6.

[0074] Comparative Example 14

[0075] This comparative example provides an integrated device for the simultaneous collection and separation of microplastics in the surface environment. The difference between this device and Example 1 is that the flotation liquid in the flotation tower is a mixture of olive oil and saturated sodium iodide solution, and the volume ratio of olive oil to saturated sodium iodide solution in the mixture is 1:6.

[0076] Application Example 1

[0077] 1. Experimental Materials

[0078] Example 1: Integrated equipment for simultaneous collection and separation of microplastics in the surface environment, thermal pyrolysis gas chromatography / mass spectrometry, circulating air pump: model 2755, range 100-500L / min, diaphragm vacuum pump: SCJ-10, adjustable water pump: XYH-910, range 0-350L / h, electric thermostatic drying oven: DH-101, electronic balance: AE160, accuracy: Class I, 0.001g, anemometer: VT115, range 0.15-30m / s, electron scanning microscope: SC-Ⅲ, filter membrane: quartz glass, pore size 0.45μm, diameter 47mm, sieve: metal, pore size 250-5000μm, high-density water-based sealant: liquid, initial curing time 7min, anhydrous ethanol: analytical grade, potassium formate: superior grade, rapeseed oil: Macklin rapeseed oil, reagent grade.

[0079] Based on the type, particle size, and abundance of microplastics in road surface sediments, several types of microplastics widely found in the ground surface environment were purchased, including polystyrene (PS), polyester (PET), polypropylene (PP), polyvinyl chloride (PVC), and butadiene rubber (BR). These microplastics were pulverized using a pulverizer and sieved to obtain plastic particles of different sizes. Each microplastic sample consisted of microplastic particles of different types and sizes, mixed in a specific mass fraction ratio, with a total mass of 1.20 g. This mixture was used to calibrate and verify the performance of the gas collection device, as detailed in Table 1.

[0080] Table 1. Density, particle size distribution, and mass percentage of different types of microplastics

[0081]

[0082] 2. Air tightness test

[0083] The integrated equipment for simultaneous collection and separation of microplastics from the ground environment was installed on different surfaces in both the laboratory and actual ground environments. The bottom edge of the gas collection hood, where it contacts the ground, was sealed using a polymer liquid sealing material. A circulating air pump was connected to the outlet, and an anemometer was connected to the inlet. Simultaneously, the vent pipe and drain pipe were closed, and a flotation solution containing 270 ml of saturated potassium formate solution and 45 ml of rapeseed oil was slowly injected into the flotation tower. After the sealing material had completely cured, the circulating air pump was started, and the outlet air velocity was gradually increased while observing the changes in air velocity at both inlets.

[0084] Conclusion: The equipment was installed on a smooth laboratory floor for airtightness testing. During the test, the air velocity at the outlet was gradually increased from 1 m / s to 28 m / s, and the air velocity at both inlets was measured using an anemometer. As the outlet air velocity gradually increased, the inlet air velocity also increased accordingly, consistently remaining at 0.498-0.499 times the outlet air velocity, indicating that the equipment has good airtightness.

[0085] The equipment was installed on a common asphalt pavement in an urban environment for air tightness testing. During the test, the air velocity at the outlet was gradually increased from 1 m / s to 28 m / s, and the air velocity at both inlets was measured using an anemometer. As the outlet air velocity gradually increased, the inlet air velocity also increased accordingly, consistently remaining between 0.497 and 0.499 times the outlet air velocity, which is essentially consistent with the outlet air velocity on a smooth laboratory surface. This indicates that the equipment can fit tightly against the asphalt pavement, exhibiting good air tightness and meeting the experimental requirements.

[0086] 3. Automated collection and separation experiment of microplastic spiked samples

[0087] (1) Steps:

[0088] a. Spread a microplastic sample evenly on the test surface with a diameter of less than 200 mm.

[0089] b. Install the integrated equipment for synchronous collection and separation of microplastics in the surface environment on the ground to be tested, and inject 270 mL of saturated potassium formate solution and 45 mL of rapeseed oil into the flotation tower.

[0090] c. Turn on the circulating air pump and circulating water pump. The circulating air pump delivers gas into the flotation tower at a wind speed of 18 m / s, and the circulating water pump extracts the liquid above the sample collection tube from the flotation tower at a flow rate of 4.8 L / min, returning the solution to the flotation tower through relevant pipelines. During this process, the microplastic sample, flotation solution, and air are in full contact within the corundum aeration device. After the circulating air pump and water pump have been running for a period of time, simultaneously turn them off to allow for settling.

[0091] d. After settling for a period of time, collect the microplastic particles in the flotation solution above the sample collection tube or the microplastic particles in the oil solution in the flotation tower, and filter them onto a constant-weight filter membrane. Dust and other particles, as well as the lower part of the flotation solution, are discharged from the flotation tower through the vent at the bottom of the slag collection hopper, and the flotation tower is rinsed clean with distilled water or ethanol.

[0092] e. After rinsing the filter membrane with distilled water or ethanol, remove the filter membrane, dry it in an oven at 40°C until it reaches constant weight, and then transfer it to a storage box for storage.

[0093] f. Detect and analyze the microplastic content in the filter membrane, and evaluate and analyze the performance of the automatic collection and separation device.

[0094] (2) Calculation of microplastic collection time for integrated equipment for simultaneous collection and separation of microplastics in the surface environment

[0095] The integrated device for simultaneous collection and separation of microplastics in the surface environment has an effective gas volume of 5.63 L and a total flotation liquid volume of 315 ml. When the wind speed at both outlets is 18 m / s, the total gas flow rate is 5.65 L / s, and the gas takes approximately 1.0 s to circulate once within the device. When the water pump flow rate is 4.8 L / min, the flotation liquid takes approximately 4 s to circulate once. Calculations using Computational Fluid Dynamics (CFD) simulation show that a stable gas flow is required to form within the integrated device. Therefore, the initial stop time is set to 12 seconds, which is the time required for three liquid circulations within the device, and subsequent sampling times are extended by 4 seconds.

[0096] The experiment was conducted according to the steps in (1) af. In step a, the integrated device for simultaneous collection and separation of microplastics in the ground environment was installed on the laboratory floor; in step c, the initial stop time was set to 12 seconds, which is the time for the liquid to circulate three times in the device, and the sampling time was extended by 4 seconds each time thereafter; in step d, the settling time was 5 minutes. Three sets of experiments were conducted in parallel, and the average value was calculated to evaluate the collection efficiency of the integrated device for simultaneous collection and separation of microplastics in the ground environment at different times. The results are shown in [reference]. Figure 6 .

[0097] pass Figure 6 It can be seen that the integrated device for simultaneous collection and separation of microplastics in the surface environment can rapidly collect spiked microplastic samples, with a collection efficiency of 85.6% at 12s, and the collection efficiency tends to reach equilibrium at 24s. Given that the complexity of microplastic particle samples in urban surface environments is higher than that in spiked experiments, the collection time for microplastics in the integrated device for simultaneous collection and separation of microplastics in the surface environment should be set to 30s.

[0098] (3) Calculation of microplastic flotation separation time for integrated equipment for simultaneous collection and separation of microplastics in the surface environment

[0099] The experiment was conducted according to steps af in (1), where a) the integrated device for simultaneous collection and separation of microplastics in the surface environment was installed on the laboratory floor; c) the device ran for 30 seconds; d) after every 30 seconds of settling, a set of microplastic samples was collected from the mixed solution in the upper layer of the flotation solution, weighed using an electronic balance, and the collection efficiency of the microplastic samples was calculated. Three sets of experiments were performed in parallel for each collection and separation experiment, and the average value was calculated. See the results below. Figure 7 .

[0100] pass Figure 7It can be seen that the integrated device for simultaneous collection and separation of microplastics in the surface environment can rapidly separate microplastic samples by flotation, with a flotation separation efficiency of 73.5% at 30s and a collection efficiency approaching equilibrium at 180s. Given that the complexity of microplastic particle samples in urban surface environments is higher than that in spiked experiments, the collection time for microplastics in the integrated device for simultaneous collection and separation of microplastics in the surface environment should be set to 3 minutes.

[0101] (4) Measurement of the efficiency of simultaneous collection and separation of microplastics in the laboratory surface environment using integrated equipment for simultaneous collection and separation of microplastics in the surface environment

[0102] The experiment was conducted according to the steps in (1) af; in step a, the integrated device for simultaneous collection and separation of microplastics in the surface environment was installed on the laboratory floor; in step c, the device ran for 30 seconds; in step d, the settling time was 3 minutes. Three sets of experiments were conducted in parallel, and the average value was calculated to evaluate the collection and flotation separation efficiency of the integrated device for simultaneous collection and separation of microplastics in the surface environment. The results are shown in Table 2:

[0103] Table 2. Collection efficiency of microplastics from laboratory surfaces using integrated equipment for simultaneous collection and separation of microplastics in the ground environment.

[0104]

[0105] As shown in Table 2, the integrated equipment for simultaneous collection and separation of microplastics in the surface environment achieved collection efficiencies of 97.3%, 96.1%, and 96.9% for microplastic spiked samples, respectively, all above 95.0%, with an average collection efficiency of 96.8%.

[0106] (5) Integrated equipment for simultaneous collection and separation of microplastics in the surface environment: Integrity test of automatic collection and separation of microplastic samples

[0107] The microplastic samples collected and separated in (4) were observed under a microscope and analyzed using microplastic analysis software to confirm the particle size of the microplastics. They were then screened and separated, and the content of each microplastic was analyzed using thermal pyrolysis gas chromatography-mass spectrometry. The integrity of the microplastic sample collection and separation was analyzed. The results are shown in [reference needed]. Figure 8 .

[0108] pass Figure 8 It can be seen that the collection and separation efficiency of polyethylene with a particle size of 2000-5000μm is the lowest at 94.9%, while the collection and separation efficiency of polystyrene with a particle size of 500-1000μm is the highest at 100%. The collection and separation efficiency of other microplastics with particle sizes is between 94.9% and 100%. Therefore, the integrated device for simultaneous collection and separation of microplastics in the surface environment of this invention can completely collect and separate microplastics of different particle sizes from paved roads.

[0109] (6) Calculation of the efficiency of the integrated equipment for simultaneous collection and separation of microplastics in the surface environment for collecting and separating microplastics in actual surface environment samples.

[0110] The experiment was conducted according to the steps in (1) af; in step a, the integrated device for synchronous collection and separation of microplastics in the surface environment was installed on the asphalt pavement; in step c, the device was run for 30s; in step d, the settling time was 3min, and the samples were collected and separated 4 times in a row. The mass of the collected microplastic samples was analyzed by gravimetric method, and the content of each microplastic particle was analyzed by thermal pyrolysis gas chromatography-mass spectrometry. The performance of the integrated device for synchronous collection and separation of microplastics in the surface environment was evaluated. The results are shown in Table 3.

[0111] Table 3. Flotation separation efficiency of the integrated equipment for simultaneous collection and separation of microplastics in the actual surface environment.

[0112]

[0113] Table 3 shows that the sample volume collected in the first collection was higher than that of the spiked microplastic sample, because the asphalt road itself contains microplastic particles. This collection included both spiked microplastic samples and naturally occurring microplastic samples in the asphalt pavement. During the second, third, and fourth collections, the amount of microplastic samples detected gradually decreased or even disappeared, indicating that the first sample collection process effectively collected microplastic particles from the asphalt pavement.

[0114] Conclusion: The integrated device for simultaneous collection and separation of microplastics in the surface environment provided by this invention has good airtightness and can adhere tightly to the ground in different surface environments through a polymer liquid sealing material. The collection time of the integrated device for simultaneous collection and separation of microplastics in the surface environment is 30 seconds, the flotation separation time is 3 minutes, the collection and separation efficiency is stable with an average collection and separation efficiency of 96.8%, and the sample integrity is between 94.9% and 100%. In addition, the integrated device for simultaneous collection and separation of microplastics in the surface environment can completely collect microplastics of different particle sizes from asphalt pavement in one pass.

[0115] Application Example 2

[0116] 1. Experimental Materials

[0117] The integrated equipment for simultaneous collection and separation of microplastics in the surface environment provided in Examples 1 and Comparative Examples 1-14 includes: a diaphragm vacuum pump (SCJ-10), a circulating air pump (model 2755, range 100-500 L / min), an adjustable water pump (XYH-910, range 0-350 L / h), an electronic balance (AE160, accuracy 1 degree, 0.001 g), an electric thermostatic drying oven (DH-101), a filter membrane (quartz glass, pore size 0.45 μm, diameter 47 mm), sodium chloride (superior grade), potassium formate (superior grade), sodium iodide (superior grade), anhydrous ethanol (analytical grade), castor oil (Aladdin, ≥99.5%), rapeseed oil (Macklin, ≥99.5%), and olive oil (Macklin, ≥99.7%).

[0118] Based on the type, particle size, and abundance of microplastics in road surface sediments, several types of microplastics widely found in the ground surface environment, such as polystyrene (PS), polyester (PET), polypropylene (PP), polyvinyl chloride (PVC), and butadiene rubber (BR), were purchased. These microplastics were pulverized using a pulverizer and sieved to obtain plastic particles of different sizes. Each microplastic sample consisted of microplastic particles of different types and sizes, mixed in a specific mass fraction ratio, with a total mass of 1.20 g. This mixture was used to calibrate and verify the performance of the gas collection device, as detailed in Table 1.

[0119] 2. Automated Collection and Separation Experiment of Microplastic Spiked Samples

[0120] a. Spread a microplastic sample evenly on the test surface with a diameter of less than 200 mm.

[0121] b. Install the integrated equipment for simultaneous collection and separation of microplastics in the ground environment of Example 1 and Comparative Examples 1-14 on the ground to be tested, and inject the corresponding flotation liquid into the flotation tower.

[0122] c. Turn on the circulating air pump and circulating water pump. The circulating air pump delivers gas into the flotation tower at a wind speed of 18 m / s, and the circulating water pump extracts the liquid above the sample collection tube from the flotation tower at a flow rate of 4.8 L / min, returning the solution to the flotation tower through relevant pipelines. During this process, the microplastic sample, flotation solution, and air are in full contact within the corundum aeration device. After the circulating air pump and water pump have been running for a period of time, simultaneously turn them off to allow for settling.

[0123] d. After settling for a period of time, collect the microplastic particles in the flotation solution above the sample collection tube or the microplastic particles in the oil solution in the flotation tower, and filter them onto a constant-weight filter membrane. Dust and other particles, as well as the lower part of the flotation solution, are discharged from the flotation tower through the vent at the bottom of the slag collection hopper, and the flotation tower is rinsed clean with distilled water or ethanol.

[0124] e. After rinsing the filter membrane with distilled water or ethanol, remove the filter membrane, dry it in an oven at 40°C until it reaches constant weight, and then transfer it to a storage box for storage.

[0125] f. Analyze the microplastic content in the filter membrane to evaluate the separation efficiency of the devices in Example 1 and Comparative Examples 1-14. See results below. Figure 9 .

[0126] pass Figure 9 It can be seen that the separation efficiencies of saturated sodium chloride solution, saturated potassium formate solution, and saturated sodium iodide solution are 40.5%, 65.6%, and 75.3%, respectively; the solution densities are 1.19 g / cm³, respectively. 3 1.58g / cm 3 1.72g / cm 3 The separation efficiency of saturated salt solutions gradually increases with increasing solution density. The separation efficiencies for castor oil, rapeseed oil, and olive oil are 90.0%, 83.3%, and 85.0%, respectively; the solution densities are 0.96 g / cm³, respectively. 3 0.92g / cm 3 0.91g / cm 3 The separation efficiency of oil solutions is generally higher than that of saturated salt solutions.

[0127] The separation efficiency of saturated salt solution + oil solution both exceeded 90.0%, with castor oil + saturated salt solution showing better separation efficiency than olive oil + saturated salt solution and rapeseed oil + saturated salt solution. Olive oil + saturated NaCl solution showed the lowest separation efficiency at 90.9%, while castor oil + saturated NaI solution showed the highest at 97.6%. When the flotation solution was a mixture of saturated potassium formate solution or saturated sodium iodide solution and oil solution, the separation efficiency was relatively high and similar, ranging from 95.6% to 97.6%.

[0128] Comprehensive analysis shows that the separation efficiency of pure saturated salt solutions or oil solutions gradually increases with increasing solution density, and pure oil solutions generally outperform saturated salt solutions. However, when saturated salt solutions are combined with oil solutions, the separation efficiency is significantly higher than when using pure saturated salt solutions or oil solutions alone. This is mainly because plastics have an affinity for oil, causing them to aggregate in the oil layer on the surface of the salt solution, thus accelerating the flotation efficiency of the flotation solution for microplastics. Among these, the separation effect of mixing saturated potassium formate and sodium iodide solutions with oil solutions is significantly better than the combination of saturated sodium chloride and oil solutions.

[0129] 3. Comparison Experiment of Separation Time for Microplastic Samples

[0130] Following the steps in section 2af, a comparative experiment was conducted on the microplastic sample separation time of the integrated device for simultaneous collection and separation of microplastics in the surface environment used in Example 1 and Comparative Examples 7-14; in step c, a set of microplastic samples was collected every 1 minute of settling, and the collection efficiency was detected and analyzed. See the results below. Figure 10 .

[0131] pass Figure 10 It can be seen that the separation times of saturated sodium iodide solution and saturated potassium formate solution + oil solution for microplastic particles of different sizes are basically the same, with both achieving a separation efficiency of over 95% within 3 minutes. However, the separation time of castor oil + saturated salt solution is slightly longer than that of rapeseed oil and olive oil + saturated salt solution. The separation times of rapeseed oil and olive oil are basically the same, both completing separation within 3 minutes.

[0132] In terms of economic viability, rapeseed oil is priced between approximately 8 and 12 yuan per unit. Olive oil prices vary depending on origin, quality grade, and processing method; even olive oil processed using less sophisticated methods generally costs between ten and several tens of yuan per unit. Regarding environmental impact, potassium formate, as a salt, exhibits good adaptability in various surface environments and poses a low risk of water and soil pollution. However, sodium iodide must be used only under strict adherence to established safety procedures, as improper handling can lead to various health risks, such as skin irritation upon contact and potential adverse effects on bodily functions upon inhalation.

[0133] Although the principles of this utility model have been described in detail above with reference to preferred embodiments, those skilled in the art should understand that the above embodiments are merely illustrative explanations of the implementation of this utility model and are not intended to limit the scope of this utility model. The details in the embodiments do not constitute a limitation on the scope of this utility model. Any obvious changes, such as equivalent transformations or simple substitutions, based on the technical solution of this utility model without departing from its spirit and scope fall within the protection scope of this utility model.

Claims

1. An integrated device for simultaneous collection and separation of microplastics in the surface environment, characterized in that, It includes a gas collection device, a circulating air pump, a circulating water pump, a cooling ring, and a flotation tower; The gas collection device includes a gas collection hood, two sets of air inlets and air outlets. The gas collection hood includes a support part and a functional part. The support part is cylindrical in shape, and the functional part is conical in shape. The top surface of the support part and the bottom surface of the functional part are closely fitted together. The air outlet is opened at the apex of the functional part, and the two sets of air inlets are symmetrically opened on both sides of the surface of the functional part. The flotation tower has conical ends and a cylindrical middle section. Outlets are located at the top and bottom of the tower. A check valve is installed at the top outlet to prevent gas backflow. The bottom outlet is connected to a vent pipe. A corundum aeration device is installed at the bottom of the tower. A cooling ring is located at the top of the tower to condense water vapor in the air above. A circulating water outlet is located at the top between the cooling ring and the corundum aeration device. A sample collection pipe is located in the middle between the circulating water outlet and the corundum aeration device. One end of the corundum aeration device is connected to a feed pipe. One end of the circulating air pump is connected to the two sets of air inlets of the gas collection device through a pipeline, and the other end is connected to the top outlet of the flotation tower through a pipeline. One end of the circulating water pump is connected to the circulating water outlet via a pipeline, and the other end is connected to the other end of the feed pipe and the air outlet of the gas collection device via a Y-shaped pipeline.

2. The integrated equipment for simultaneous collection and separation of microplastics in the surface environment according to claim 1, characterized in that, The flotation tower is filled with flotation solution; When the integrated equipment for synchronous collection and separation of microplastics in the surface environment is not in operation, the settling liquid level of the flotation solution is 30 mm higher than that of the sample collection tube and lower than that of the circulation outlet. When the integrated equipment for synchronous collection and separation of microplastics in the surface environment is working, the working liquid level of the flotation solution is at least 10 mm higher than that of the circulating water outlet.

3. The integrated device for simultaneous collection and separation of microplastics in the surface environment according to claim 2, characterized in that, The flotation solution is a mixture of rapeseed oil and saturated potassium formate solution; In the mixture of rapeseed oil and saturated potassium formate solution, the volume ratio of rapeseed oil to saturated potassium formate solution is 1:

6.

4. The integrated equipment for simultaneous collection and separation of microplastics in the surface environment according to claim 1, characterized in that, The bottom diameter of the functional part of the gas collecting hood is the same as the diameter of the supporting part of the gas collecting hood; The ratio of the bottom diameter of the functional part of the gas collection hood to its cone height is 10:1, and the ratio of the bottom diameter of the support part of the gas collection hood to its column height is 10:

1. Preferably, the bottom diameter of the functional part of the gas collecting hood is 200mm and the cone height is 20mm, and the bottom diameter of the support part of the gas collecting hood is 200mm and the column height is 20mm.

5. The integrated device for simultaneous collection and separation of microplastics in the surface environment according to claim 1, characterized in that, The diameter of the central cylindrical shape of the flotation tower is 60 mm, and the height of the column is 1000 mm. The flotation tower has two conical bases with a diameter of 60 mm and a height of 30 mm.

6. The integrated device for simultaneous collection and separation of microplastics in the surface environment according to claim 1, characterized in that, The lowest point of the cooling ring is located at 700 mm above the height of the cylindrical column in the middle of the flotation tower. The circulating outlet is located at 600 mm above the height of the central cylindrical section of the flotation tower. The sample collection tube is located at 500 mm above the height of the central cylindrical column of the flotation tower.

7. The device according to claim 1, wherein, The cooling ring contains a polymeric refrigerant of polyacrylic acid polyol, or a cooling solution. The flotation tower is made of plexiglass. The pipes used in the integrated surface environment microplastic collection and separation equipment are all made of silicone.

8. The integrated device for simultaneous collection and separation of microplastics in the surface environment according to claim 1, characterized in that, The corundum aeration device is a sphere with a diameter of 50 mm, and its surface is covered with holes with a diameter of 5 mm. A check valve is provided at the middle part of the connection between the gas outlet of the gas collection device and the Y-shaped pipe.

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