Micro-plastic cyclone separation device based on microbubble assistance

Abstract

The invention discloses a micro-plastic cyclone separation device based on microbubble assistance. The cyclone separation main body comprises an upper cylindrical section barrel body and a lower conical section barrel body; the water outlet end of the tangential water inlet pipe is led into the upper cylindrical section barrel and is tangent to the inner wall of the barrel; the top overflow pipe is led into the cylinder body from the top of the upper cylindrical section cylinder body; a drain outlet is formed in the bottom of the lower conical section cylinder body; the microbubble generation assembly is arranged at the center of the lower part of the lower conical section cylinder; the water inlet end of the middle clear water outlet pipe is communicated into the upper cylindrical section barrel body and is positioned at 40-60% of the radius of the barrel body; the ultrasonic vibration output end of the ultrasonic vibration assembly is in contact with the outer wall of the upper cylindrical section barrel; and the electric field induction assembly is arranged in the upper cylindrical section barrel, so that efficient capture and separation of micro plastic particles are realized in a compact single device on the premise of not using chemical agents and not depending on an easily-blocked filter screen.

Description

Technical Field

[0001] This invention relates to the field of microplastic separation technology, and in particular to a microplastic cyclone separation device based on microbubble-assisted separation. Background Technology

[0002] With the widespread use of plastic products in production and daily life, microplastic pollution (typically referring to plastic particles or fibers with a diameter of less than 5 mm) has become a global environmental problem. Microplastics are widely present in oceans, rivers, and urban sewage. Due to their small particle size and large specific surface area, they readily adsorb persistent organic pollutants and heavy metals, and accumulate through the food chain, posing a potential threat to the ecological environment and human health. Currently, urban sewage treatment plants are an important line of defense against microplastics entering natural water bodies. However, traditional sewage treatment processes (such as screens and sedimentation tanks) are mainly designed for larger floating objects or heavier silt, and their removal effect on tiny microplastics with a density close to that of water is limited.

[0003] To improve the removal rate of microplastics, existing improvement technologies mainly include membrane filtration, air flotation, and hydrocyclone separation. The shortcomings and deficiencies of these existing technologies are as follows:

[0004] 1. Filtration technologies are prone to clogging and have high maintenance costs: When using screens or membrane filters to intercept microplastics, as the operating time increases, microplastics and biofilms in the water are very likely to clog the filter pores (membrane fouling problem). This not only leads to a sharp increase in water pressure drop and a decrease in treatment capacity, but also requires frequent backwashing or chemical cleaning, which greatly increases operating energy consumption and maintenance costs.

[0005] 2. Conventional dissolved air flotation technology relies on chemical agents: In order to improve the binding efficiency of air bubbles and microplastics, traditional dissolved air flotation processes usually require the addition of coagulants or flocculants (such as PAC, PAM) to increase the particle volume. This not only increases operating costs, but the added chemical agents may also cause secondary chemical pollution of water bodies, which does not conform to the concept of green and environmentally friendly treatment.

[0006] 3. Poor separation effect of traditional hydrocyclones: In a conventional swirling field, the centrifugal force and centripetal buoyancy experienced by lightweight or neutral density microplastics are very small, making it difficult to separate them effectively. As a result, most microplastics pass through the equipment with the water flow, resulting in poor separation effect.

[0007] 4. Complex structure and large footprint: Existing microplastic treatment equipment often separates the flotation tank and sedimentation tank, or requires a complex high-pressure dissolved air tank and return pump system, resulting in a large equipment size that is difficult to apply in space-constrained scenarios (such as small sewage treatment plants or shipborne equipment). Summary of the Invention

[0008] This invention provides a microbubble-assisted microplastic cyclone separation device, which solves the technical problems of existing technologies such as easy clogging and high maintenance costs of filtration technology, reliance on chemical agents for conventional air flotation technology, poor separation effect of traditional hydrocyclones, complex structure, and large footprint. It achieves efficient capture and separation of microplastic particles in a compact single device without the use of chemical agents or reliance on easily clogged filters.

[0009] This invention provides a microbubble-assisted microplastic cyclone separation device, comprising: a cyclone separation body, a tangential water inlet pipe, a microbubble generating component, an ultrasonic vibration component, an electric field induction component, a top overflow pipe, and a middle clear water outlet pipe; the cyclone separation body has an upper cylindrical section and a lower conical section; the outlet end of the tangential water inlet pipe is connected to the upper cylindrical section and is tangential to the inner wall of the upper cylindrical section; the top overflow pipe extends from the upper cylindrical section... The top of the upper cylindrical section is connected to the upper cylindrical section; the bottom of the lower conical section is a drain outlet; the microbubble generating component is located at the lower center of the lower conical section; the inlet of the middle clear water outlet pipe is connected to the upper cylindrical section and located at 40%-60% of the radius of the upper cylindrical section; the ultrasonic vibration output end of the ultrasonic vibration component is in contact with the outer wall of the upper cylindrical section; and the electric field induction component is located in the upper cylindrical section.

[0010] Specifically, the microbubble generating component includes: an aeration disc, a hollow connecting bracket, and an air supply pipe; one end of the hollow connecting bracket is connected to the aeration disc, and the other end of the hollow connecting bracket is connected to the inner wall of the lower conical section cylinder; the air supply pipe is disposed in the hollow connecting bracket; one end of the air supply pipe is connected to the aeration disc, and the other end of the air supply pipe extends from the inner wall of the lower conical section cylinder and is connected to an air pump.

[0011] Specifically, the microbubble generating component further includes a pressure regulating valve and a flow meter; both the pressure regulating valve and the flow meter are installed in the gas supply pipeline.

[0012] Specifically, the ultrasonic vibration assembly includes: an ultrasonic transducer, a conductive plate, and a clamp; the ultrasonic vibration output end of the ultrasonic transducer is connected to the conductive plate, and the conductive plate is in contact with the outer wall of the upper cylindrical section; the ultrasonic transducer is fastened to the upper cylindrical section by the clamp.

[0013] Specifically, the electric field induction component includes: an upper electrode ring, a lower electrode ring, an upper hollow support, and a lower hollow support; one end of the upper hollow support is connected to the upper electrode ring, and the other end of the upper hollow support is connected to the inner wall of the upper cylindrical section; one end of the lower hollow support is connected to the lower electrode ring, and the other end of the lower hollow support is connected to the inner wall of the upper cylindrical section; wires are present in both the upper and lower hollow supports; one end of each wire is connected to the upper electrode ring and the lower electrode ring respectively, and the other end of each wire extends from the inner wall of the upper cylindrical section and is connected to a power source, so that the upper electrode ring is positively charged and the lower electrode ring is negatively charged.

[0014] Specifically, the upper electrode ring, lower electrode ring, upper hollow support, and lower hollow support are all covered with a polytetrafluoroethylene or epoxy resin insulating layer.

[0015] Specifically, a guide plate is hinged to the outlet end of the tangential water inlet pipe.

[0016] Specifically, it also includes: a guide cylinder and fastening bolts; the middle clean water outlet pipe passes through the guide cylinder into the upper cylindrical section; a through hole is provided on the side wall of the guide cylinder; the fastening bolts extend through the through hole to fasten the middle clean water outlet pipe.

[0017] Specifically, the inlet end of the central water outlet pipe has a bent structure.

[0018] Specifically, there is a threaded through hole at the top of the upper cylindrical section, and the top overflow pipe has external threads. The external threads and the threaded through hole are connected by threads.

[0019] One or more technical solutions provided in this invention have at least the following technical effects or advantages:

[0020] 1. The cyclone separator consists of an upper cylindrical section and a lower conical section. The outlet of the tangential inlet pipe enters the upper cylindrical section and is tangential to its inner wall. A top overflow pipe enters the upper cylindrical section from its top. The bottom of the lower conical section serves as the drain outlet. A microbubble generator is located at the lower center of the lower conical section. The inlet of the middle clear water outlet pipe enters the upper cylindrical section and is located at 40%-60% of its radius. The ultrasonic vibration output end of the ultrasonic vibration assembly contacts the outer wall of the upper cylindrical section. An electric field induction assembly is located within the upper cylindrical section. The tangential inlet pipe allows pressurized wastewater containing microplastics to enter the cyclone separator tangentially, forcing the fluid to rotate at high speed within the cylinder, thus generating a strong centrifugal force field. The upper cylindrical section of the cyclone separator stabilizes the initial flow field, while the lower conical section accelerates the rotating fluid, enhancing centrifugal separation. A microbubble generator produces microbubbles with diameters ranging from 10 to 100 micrometers. These bubbles move upwards from the bottom, contacting the rotating flow field in the opposite or cross-flow direction. Utilizing the hydrophobic properties of the microplastic surface, the bubbles actively capture and adhere to the microplastic particles, forming a "bubble-microplastic" composite. This significantly reduces the apparent density of the microplastics, making them more likely to aggregate and float towards the central axis. Even suspended microplastics that are normally difficult to settle can rapidly aggregate and float towards the central axis under the combined effects of buoyancy and centripetal force, achieving efficient capture of lightweight, near-neutral density microplastics. The least dense substance, namely the microplastic scum with attached bubbles, is collected by the top overflow pipe and discharged under the action of the central negative pressure zone. The intermediate clear liquid, after centrifugal and flotation separation, is led out by the central clear water outlet pipe. Heavy impurities with a density significantly greater than water (such as sand and large dirt particles) are thrown against the vessel wall by centrifugal force and sink along the wall surface, then discharged through the drain port at the bottom of the lower conical section of the cylinder. This achieves the technical effect of simultaneous separation of the three phases—light phase flotation, heavy phase sedimentation, and medium phase purification—within a single device. The device is compact, significantly reducing the number of equipment and floor space required, and simplifying the process flow and piping system. Furthermore, ultrasonic vibration components output ultrasound, which propagates along the cylinder, causing high-frequency vibration in localized areas of the microplastics. This reduces the boundary layer thickness on the particle surface, increases the random vibration migration rate of the particles, and thus increases the probability of contact with air bubbles, with even better results for fibrous microplastics. An electric field induction component generates a low-voltage electric field, which makes the surface charge of the microplastics uniform. The air bubbles naturally carry a negative charge, thus inducing the microplastics to approach the air bubbles and improving adhesion efficiency.Furthermore, this invention employs a pure fluid dynamics separation mechanism, eliminating the need for physical filtration media such as screens, filter cloths, and filter membranes. Solid-liquid separation is achieved entirely through cyclone centrifugal stratification and microbubble adhesion separation. This allows for long-term continuous operation without frequent shutdowns for cleaning, reducing backwashing water, chemical consumption, and labor maintenance costs. It also lowers equipment failure rates and downtime risks, resulting in significantly lower overall operating costs compared to microplastic removal processes that rely on filtration units. This invention does not rely on coagulants, flocculants, or other chemical agents. Instead, it achieves microplastic aggregation and separation through the synergistic effect of microbubble physical adsorption and cyclone force fields. This enables highly efficient removal of microplastics under all physical operating conditions, avoiding issues related to chemical agent procurement, dosage, and residue. This reduces long-term operating costs and minimizes the impact on effluent quality and downstream treatment units, aligning with green environmental protection and sustainable development requirements.

[0021] 2. This invention, through the combination of adjustable bubbles and adjustable flow fields, allows operators to adjust bubble size and swirling characteristics according to water quality characteristics, thereby optimizing the bubble-microplastic collision frequency and adhesion efficiency, and controlling the interface position of the light, heavy, and medium phases. Specifically, by changing the aperture of the aeration disc, adjusting the air supply pressure, inlet shear force, and inlet velocity, the microbubble particle size can be controlled within a certain range, enabling microplastics of different morphologies (fragmented, spherical, and fibrous) to obtain optimal adhesion conditions. The swirling intensity and separation interface position can be changed by adjusting the overflow pipe insertion depth, inlet flow rate, and inlet pressure, resulting in better resistance to shock loads and water quality stability, which is beneficial for ensuring that the water quality of subsequent treatment units or direct discharge / reuse meets standards.

[0022] 3. By installing both the pressure regulating valve and the flow meter in the gas supply pipeline, the amount of bubbles generated can be controlled.

[0023] 4. A guide plate is hinged at the outlet end of the tangential water inlet pipe. By adjusting the rotation of the guide plate, the cross-sectional area of ​​the water inlet and the incident angle can be changed, thereby achieving adjustable vortex intensity.

[0024] 5. The cyclone separator, tangential inlet pipe, microbubble generator, ultrasonic vibration assembly, electric field induction assembly, top overflow pipe, and central clear water outlet pipe in this invention can all be modularly designed to the required dimensions. Multiple components can be connected in parallel or series to form a multi-stage separation system. For large-scale projects, the processing capacity can be scaled up by increasing the number of components without redesigning the process system. For applications with high water quality requirements, the microplastic removal rate and water quality stability can also be improved step by step through multi-stage series connection. Attached Figure Description

[0025] Figure 1 A schematic diagram of the overall structure of the microbubble-assisted microplastic cyclone separation device provided in an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the ultrasonic vibration component in the microbubble-assisted microplastic cyclone separation device provided in an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of the tangential water inlet pipe 22 in the microbubble-assisted microplastic cyclone separator provided in an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of the structure of the central clear water outlet pipe 23 in the microbubble-assisted microplastic cyclone separator provided in an embodiment of the present invention;

[0029] Among them, 1-upper cylindrical section, 2-lower conical section, 3-top overflow pipe, 4-drain valve, 5-aeration disc, 6-hollow connecting bracket, 7-radial clearance, 8-ultrasonic transducer, 9-conduction plate, 10-clamp, 11-external main unit, 12-upper electrode ring, 13-lower electrode ring, 14-upper hollow bracket, 15-lower hollow bracket, 16-guide plate, 17-rotating shaft, 18-guide cylinder, 19-fastening bolt, 20-drain valve, 21-bent structure, 22-tangential water inlet pipe, 23-middle clean water outlet pipe, 24-waterproof sealing terminal. Detailed Implementation

[0030] This invention provides a microbubble-assisted microplastic cyclone separation device, which solves the technical problems of existing technologies such as easy clogging and high maintenance costs of filtration technology, reliance on chemical agents in conventional air flotation technology, poor separation effect, complex structure and large footprint of traditional hydrocyclones. It achieves efficient capture and separation of microplastic particles in a compact single device without the use of chemical agents and without relying on easily clogged filters.

[0031] The technical solutions in the embodiments of the present invention are designed to achieve the above-mentioned technical effects, and the overall concept is as follows:

[0032] The cyclone separator body forms a space capable of generating outer cyclone (descending, velocity 3-7 m / s), medium cyclone (quasi-stable region, velocity 1-3 m / s), and inner cyclone (ascending, velocity 1-4 m / s), creating a multi-layered cyclone velocity and pressure distribution structure within the device. This structure provides different fluid motion paths for the sedimentation of heavy particles and the flotation of microplastics, forming the physical basis for the three-phase separation of this invention. The inlet pipe is tangentially arranged along the outer wall of the upper cylindrical section, with its axis tangential to the cross-section of the upper cylindrical section, forming a tangential inflow. After the wastewater containing microplastics enters the cyclone separator body tangentially at a velocity of 3-8 m / s, a huge radial pressure gradient is formed inside the cyclone separator body. The pressure is highest at the outer edge (maximum centrifugal force), and lowest at the central axis (even forming a negative pressure column of air). Specifically, under the constraint of the inner wall of the cyclone separator body, a high-speed outer cyclone is formed, and heavy particles (such as silt) are thrown towards the wall by high centrifugal force, forming a spiral descent path. The light phase microplastic-bubble composite is drawn towards the negative pressure zone at the center by the pressure difference, entering the inner vortex, and then discharged from the top overflow pipe with the rising flow. The middle phase, clear water, is neither thrown too far nor drawn into the center, but remains near the relatively stable "zero-velocity envelope." Because the water at this location has a certain static pressure (derived from the rotational velocity) and is higher than the atmospheric pressure (or back pressure) outside the outlet pipe, it is naturally guided out of the central clear water outlet pipe under the influence of the pressure difference. This three-zone coupling structure allows microplastics and heavy particles to be guided to different flow layers within the same cavity, thereby improving separation efficiency and reducing the device size.

[0033] The working process of this device can be roughly divided into the following three physical stages:

[0034] Swirl formation and centrifugal stratification stage: Wastewater containing microplastics enters the upper cylindrical section at high speed through the tangential inlet pipe, forming an external swirling flow under the constraint of the cylinder wall and moving downwards. During this process, heavy particles (silt) with a density greater than water are thrown towards the cylinder wall by strong centrifugal force and spiral down along the wall surface, eventually being discharged from the drain port at the bottom of the lower conical section.

[0035] Bubble capture and density modification stage: The microbubble generating component is activated, producing a large number of microbubbles. Under the influence of buoyancy, the microbubbles move upwards, passing through the rotating fluid layer. Due to the natural hydrophobicity of microplastics (such as polyethylene and polypropylene), microbubbles easily adhere to the surface of the microplastics, forming a "microplastic-bubble" composite. The overall apparent density of this composite is significantly reduced (far less than that of water), which allows even microplastics with a density close to that of water to obtain enormous centripetal buoyancy.

[0036] Internal swirling migration and final separation stage: Under the combined effects of buoyancy and the low-pressure zone at the center of the fluid, the "microplastic-bubble" composite rapidly migrates towards the central axis of the swirling separator and enters the upward-flowing internal swirling flow (air column region). This upward flow carries the microplastics upward and is eventually discharged through the top overflow pipe, achieving microplastic recovery. The clean water, after removing impurities and microplastics, is mainly concentrated in the middle region of the swirling radius and is discharged through the central clean water outlet pipe.

[0037] Furthermore, ultrasonic vibration is output through an ultrasonic vibration component, increasing the random vibration migration rate of particles and thus improving the probability of contact with bubbles. A low-voltage electric field is also generated by an electric field induction component, inducing microplastics to approach the bubbles and improving adhesion efficiency.

[0038] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0039] like Figure 1As shown, the microbubble-assisted microplastic cyclone separation device provided in this embodiment of the invention includes: a cyclone separation body, a tangential water inlet pipe 22, a microbubble generating component, an ultrasonic vibration component, an electric field induction component, a top overflow pipe 3, and a middle clear water outlet pipe 23; the cyclone separation body has an upper cylindrical section 1 and a lower conical section 2 structure; the outlet end of the tangential water inlet pipe 22 is connected to the upper cylindrical section 1 and is tangential to the inner wall of the upper cylindrical section 1 (i.e., tangential water inlet); the top overflow pipe 3 is connected to the upper cylindrical section 1 from the top; the bottom of the lower conical section 2 is a drain outlet, and the drain outlet can adjust the drain cycle (draining once every 5-20 minutes) through a controllable drain valve 4. The microbubble generating component is located at the lower center of the lower conical section 2; the inlet of the middle clear water outlet pipe 23 enters the upper cylindrical section 1 and is located at 40%-60% of the radius of the upper cylindrical section 1; the ultrasonic vibration output end of the ultrasonic vibration component contacts the outer wall of the upper cylindrical section 1; and the electric field induction component is located in the upper cylindrical section 1. Specifically, the upper cylindrical section 1 and the lower conical section 2 are connected by flanges or welding, and the transition area is ground into a smooth curved surface to reduce flow field interference and form a continuous and smooth swirling cavity inside. The diameter of the upper cylindrical section 1 is 150-300 mm, and the height is 200-500 mm; the height of the lower conical section 2 is 300-600 mm, the cone angle is 10°-30°, and the diameter of the bottom drain outlet is 20-50 mm. An initial swirling flow field is formed in the upper cylindrical section 1 to stabilize the velocity distribution of the external swirling flow. The swirling radius is gradually compressed in the lower conical section 2, increasing the fluid rotation speed and improving the centrifugal stratification effect. One end of the tangential inlet pipe 22 is connected to an external water pump. The diameter of the tangential inlet pipe 22 is DN25-DN40, made of polyvinyl chloride, and can be fixed via flange or thread. The axis of the tangential inlet pipe 22 is tangential to the inner wall of the upper cylindrical section 1, and its tangential inlet velocity is designed to be 3-5 m / s to ensure the formation of a stable, strong centrifugal field. The inlet end of the middle clear water outlet pipe 23 is located 50 mm below the connection between the upper cylindrical section 1 and the lower conical section 2. It uses a DN40 outlet pipe, and the flow rate is adjusted via a ball valve.

[0040] The structure of the microbubble generating component is described in detail. The microbubble generating component includes: an aeration disc 5, a hollow connecting bracket 6, and an air supply pipe. One end of the hollow connecting bracket 6 is connected to the aeration disc 5, and the other end is connected to the inner wall of the lower conical section cylinder 2. The air supply pipe is housed within the hollow connecting bracket 6. One end of the air supply pipe is connected to the aeration disc 5, and the other end extends from the inner wall of the lower conical section cylinder 2 and connects to an air pump. The pressure is adjusted to 0.05-0.45 MPa via a pressure regulating valve. Specifically, the air supply pipe is made of φ10 stainless steel. The aeration disc 5 is made of sintered titanium powder, alumina ceramic or carbon composite material, with a pore size range of 3-30 μm and a pore density of 3000-6000 pores / cm². It is fixed at a distance of 50-150 mm above the bottom of the lower conical section cylinder 2. The outer swirling heavy phase sludge slides down the inner wall of the swirling separator at high speed. Because of the hollow connecting support 6, there is a radial gap 7 between the aeration disc 5 and the inner wall of the swirling separator. Therefore, the heavy phase sludge will not enter the aeration disc 5, nor will it affect the generation and rising path of microbubbles.

[0041] To control the amount of bubbles generated, the microbubble generating assembly also includes a pressure regulating valve and a flow meter; both the pressure regulating valve and the flow meter are installed in the gas supply pipeline.

[0042] like Figure 2 As shown, the structure of the ultrasonic vibration assembly is described in detail. The ultrasonic vibration assembly includes: an ultrasonic transducer 8, a conductive plate 9, and a clamp 10. The ultrasonic vibration output end of the ultrasonic transducer 8 is connected to the conductive plate 9, and the conductive plate 9 is in contact with the outer wall of the upper cylindrical section 1. The ultrasonic transducer 8 is fastened to the upper cylindrical section 1 by the clamp 10. The stainless steel annular clamp 10 surrounds the entire upper cylindrical section 1. The clamp 10 presses against the back of the ultrasonic transducer 8 / conductive plate 9 assembly, and a centripetal radial pressure is applied by tightening the bolts of the clamp 10. Specifically, the ultrasonic transducer 8 is a piezoelectric ceramic with a power of 10-80W and a frequency of 20-40 kHz, and is linked to the external host 11 for start-stop operation. The conductive plate 9 is an aluminum or stainless steel coupling plate to ensure that the vibration energy is transmitted to the liquid inside the upper cylindrical section 1.

[0043] In order to transmit the high-frequency mechanical vibration generated by the ultrasonic transducer 8 to the conductive plate 9 without damage, the connection between the ultrasonic transducer 8 and the conductive plate 9 is achieved by strong adhesive bonding or mechanical pressing.

[0044] To ensure that there is no gap between the transmission plate 9 and the cylinder wall, and to further ensure that the high-frequency mechanical vibration is transmitted to the transmission plate 9 without damage, the inner surface of the transmission plate 9 is an arc surface that matches the outer curvature of the upper cylindrical section cylinder 1 (or is filled with flexible material), so that the wall surface of the upper cylindrical section cylinder 1 itself is forced to become a "vibration membrane" to radiate ultrasonic energy into the internal liquid.

[0045] The structure of the electric field induction assembly is described in detail. The electric field induction assembly includes: an upper electrode ring 12, a lower electrode ring 13, an upper hollow support 14, and a lower hollow support 15. One end of the upper hollow support 14 is connected to the upper electrode ring 12, and the other end is connected to the inner wall of the upper cylindrical section 1. One end of the lower hollow support 15 is connected to the lower electrode ring 13, and the other end is connected to the inner wall of the upper cylindrical section 1. Both the upper hollow support 14 and the lower hollow support 15 contain wires. One end of each wire is connected to the upper electrode ring 12 and the lower electrode ring 13, respectively, and the other end extends from the inner wall of the upper cylindrical section 1 and connects to a power source, causing the upper electrode ring 12 to be positively charged and the lower electrode ring 13 to be negatively charged, thus forming a longitudinal electric field. Specifically, a waterproof sealing terminal is provided at the connection between the hollow support and the inner wall of the upper cylindrical section 1. The upper electrode ring 12 and the lower electrode ring 13 are made of titanium coated with ruthenium-iridium. The upper hollow support 14 and the lower hollow support 15 are both T-shaped buckles. The root of the T-shaped buckle is fixed to the inner wall of the upper cylindrical section 1, and the head of the T-shaped buckle grips the upper electrode ring 12 and the lower electrode ring 13.

[0046] To avoid electrochemical reactions, the upper electrode ring 12, lower electrode ring 13, upper hollow support 14, and lower hollow support 15 are all covered with a polytetrafluoroethylene or epoxy resin insulating layer.

[0047] To control the influent shear force and improve the separation effect, such as Figure 3As shown, a guide plate 16 is hinged to the outlet end of the tangential inlet pipe 22. Specifically, a shaft hole is drilled on the top (or side) of the outlet end of the tangential inlet pipe 22, and a rotating shaft 17 is passed vertically (or horizontally, depending on the shape of the inlet pipe) through the pipe wall. A sealing ring or stuffing box is installed at the point where the rotating shaft 17 passes through the pipe wall to prevent sewage leakage while allowing the rotating shaft 17 to rotate. One edge of the guide plate 16 is rigidly fixed to the rotating shaft 17 by welding or screws. The guide plate 16 hangs in the flow channel like a door. When the rotating shaft 17 rotates, the guide plate 16 swings accordingly. The size of the guide plate 16 is slightly smaller than the inner diameter of the inlet pipe (or the height of the rectangular flow channel) to ensure that it can swing freely inside the inlet pipe without getting stuck. A knob or handle is directly fitted onto the top end of the rotating shaft 17 extending outside the pipe and secured with a set screw or keyway. When the operator rotates the knob or handle externally, it drives the rotating shaft 17 to rotate, which in turn causes the internal guide plate 16 to deflect. Alternatively, the top of the rotating shaft 17 extending outside the pipe can be connected to the power output shaft of an external motor, thus achieving automatic control of the deflection of the guide plate 16. The guide plate 16 is initially fully open, at which point the inlet cross-sectional area is at its maximum and the flow velocity is relatively slow. When the rotating shaft 17 is rotated, the guide plate 16 swings towards the center of the flow channel (i.e., "hinged" movement), at which point the effective cross-sectional area of ​​the inlet flow channel decreases. With a constant flow rate, the water is forced to accelerate through the narrow opening, increasing the tangential velocity and centrifugal force as it enters the cyclone separator. Simultaneously, the faster flow velocity generates stronger shear force, which helps to break up microbubbles more effectively, improving the separation effect.

[0048] To adjust the distance between the clean water inlet and the inner wall, such as Figure 4 As shown, it also includes: a guide cylinder 18 and a fastening bolt 19; a central clean water outlet pipe 23 extends from the guide cylinder 18 into the upper cylindrical section 1; a through hole is provided on the side wall of the guide cylinder 18; the fastening bolt 19 extends through the through hole to fasten the central clean water outlet pipe 23. A waterproof sealing terminal 24 is provided at the connection between the central clean water outlet pipe 23 and the upper cylindrical section 1. By adjusting the length of the central clean water outlet pipe 23, the distance between the clean water inlet and the inner wall can be adjusted.

[0049] In order to make the inlet end of the central clean water outlet pipe 23 tangent to the incoming water flow and improve the clean water discharge efficiency, the inlet end of the central clean water outlet pipe 23 is a bent structure 21.

[0050] To adjust the position of the separation interface, a threaded through hole is provided at the top of the upper cylindrical section 1, and the top overflow pipe 3 has external threads. The external threads and the threaded through hole are connected by threads. Specifically, the diameter of the top overflow pipe 3 is 20-60 mm, the insertion depth is 10%-40% of the height of the upper cylindrical section 1, and the flow rate accounts for 3-10% of the total flow rate. It is used to discharge the foam flow formed by the microplastic-bubble composite.

[0051] To achieve adjustable bottom drainage, the drainage port at the bottom of the lower conical section cylinder 2 is a flange interface or a threaded interface, and is equipped with a set of drainage heads of different diameters (e.g., 20, 30, 40 mm), which can be manually replaced according to the sand content.

[0052] To achieve efficient removal of microplastics from wastewater, the specific operating steps of the microbubble-assisted microplastic cyclone separator provided in this embodiment of the invention are as follows:

[0053] Step 1: Startup Preparation

[0054] Close the drain valve 4 at the bottom of the lower conical section cylinder 2;

[0055] Open the drain valve 20 in the middle clean water outlet pipe 23 and the channel of the top overflow pipe 3;

[0056] Check the sealing of the connection between the air supply pipe and the microporous aeration disc 5.

[0057] Step 2: Activate the microbubble generator.

[0058] Turn on the air pump and adjust the air supply pressure to 0.25 MPa to ensure that the aeration disc 5 produces a uniform milky white microbubble mist airflow. Aerating before water intake prevents sewage backflow and clogging of the aeration disc 5.

[0059] Step 3: Start the water inlet system

[0060] The inlet pump is started, and wastewater containing microplastics is tangentially introduced into the cyclone separator body through the tangential inlet pipe 22 at a flow rate of 4 m³ / h. This high-speed tangential motion is converted into a strong rotating centrifugal field inside the cylinder, forming a unique pressure distribution (pressure energy). Under the action of centrifugal force, the wastewater containing microplastics is forcibly pushed against the cylinder wall, forming an outer vortex. At this time, a huge radial pressure gradient is formed inside the cyclone separator body (high pressure at the wall surface, low pressure at the center), specifically:

[0061] External swirling downflow: 3-6 m / s

[0062] Medium swirling flow: 1-3 m / s

[0063] Internal swirling upflow: 1-4 m / s

[0064] Step 4: Steady-state operation and separation process

[0065] Heavy particles: descend along the outer swirling flow and adhere to the wall, then are discharged through the drain outlet;

[0066] Microplastics: Microbubbles (upward flow) travel along an upward path through the rotating fluid and come into countercurrent contact with the rotating water flow (downward flow). The bubbles rapidly capture microplastic particles (such as polyethylene PE and polypropylene PP fragments) in the water, forming a "microplastic-bubble" composite. The apparent density of this composite is much lower than that of water, thus greatly increasing the density difference between microplastics and water. Under the influence of negative pressure and buoyancy in the central vortex separation zone, they tend to accumulate in the inner vortex zone and the upward flow zone.

[0067] Light phase fluid: rises with the internal vortex and enters the top overflow pipe 3;

[0068] Central clear water: flows smoothly in the middle layer area and is discharged through the central clear water outlet pipe 23.

[0069] Typical data (test samples: PE microplastics with a particle size of 100-300μm):

[0070] Microplastic removal rate: ≥86%

[0071] Heavy particle removal rate: ≥95%

[0072] Turbidity of clear water: <10 NTU

[0073] Step 5: Shutdown Process

[0074] Stop the water inlet pump;

[0075] Maintain aeration for 3-5 minutes to purge residual impurities from the water and pipes;

[0076] Finally, turn off the air pump.

[0077] In summary, this invention addresses the problems of low separation efficiency of lightweight microplastics, easy clogging of filter units, high dependence on chemical agents, and large and complex device size in existing technologies. It proposes a microbubble-assisted microplastic cyclone separation device. Utilizing the radial pressure gradient and axial velocity distribution of the cyclone field, heavy particles naturally aggregate in the outer cyclone and are discharged from the bottom. Lightweight microplastics with attached bubbles rise along the central inner cyclone and are discharged from the top overflow pipe 3. The relatively clear water in the middle layer is led out from the central clear water outlet pipe 23. By rationally designing the spatial position, elevation, and opening form of each outlet, automatic stratification and directional discharge of the three phases within the same space are achieved, significantly reducing the number of devices and floor space, simplifying the process flow and piping system. It is particularly suitable for small wastewater treatment plants, shipborne systems, or mobile water treatment equipment in situations with limited space. Furthermore, because this invention employs a filterless structure based on a purely physical field, utilizing centrifugal vortex and flotation principles for separation, it replaces traditional screens or membrane filtration components. Therefore, there is no risk of physical pores being clogged by biofilms or particulate matter. The device can operate continuously for extended periods without frequent backwashing or chemical cleaning, significantly reducing energy consumption and downtime maintenance time and labor costs. It is particularly suitable for treating wastewater with large fluctuations in water quality and high impurity content. This invention utilizes the shear force of a high-speed rotating flow field and the high specific surface area of ​​microbubbles to directly achieve collision and adhesion between bubbles and microplastics. The entire treatment process requires no chemical additives, avoiding secondary chemical pollution of the water body and saving the expensive cost of continuously purchasing chemicals, aligning with the trend of green and environmentally friendly technologies. In addition, this invention also exhibits good adaptability to operating conditions and parameter adjustability, making it highly adaptable and widely applicable. It can be applied to various situations such as municipal sewage, industrial wastewater, ship ballast water, and river and lake water intake, improving the versatility and engineering application value of the device. The embodiments of the present invention also facilitate modular configuration according to different scales and different water output requirements, making the design flexible and expansion easy, reducing engineering design and manufacturing costs, and improving practicality and promotion value.

[0078] Any aspects of this invention not described in detail in the embodiments are well-known techniques to those skilled in the art. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this invention and not to limit it. Although this invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this invention without departing from the spirit and scope of this invention, and all such modifications and substitutions should be covered within the scope of the claims of this invention.

Claims

1. A microplastic cyclonic separation device based on microbubble assistance, characterized by, It comprises: A cyclone separation main body, a tangential water inlet pipe, a micro-bubble generating assembly, an ultrasonic vibration assembly, an electric field induction assembly, a top overflow pipe and a middle clear water outlet pipe; the cyclone separation main body is an upper cylindrical section cylinder and a lower conical section cylinder structure; the water outlet end of the tangential water inlet pipe is connected to the upper cylindrical section cylinder and is tangent to the inner wall of the upper cylindrical section cylinder; the top overflow pipe is connected to the upper cylindrical section cylinder from the top of the upper cylindrical section cylinder; the bottom of the lower conical section cylinder is a sewage outlet; the micro-bubble generating assembly is arranged at the lower center of the lower conical section cylinder; the water inlet end of the middle clear water outlet pipe is connected to the upper cylindrical section cylinder and is located at 40%-60% of the radius of the upper cylindrical section cylinder; the ultrasonic vibration output end of the ultrasonic vibration assembly is in contact with the outer wall of the upper cylindrical section cylinder; the electric field induction assembly is arranged in the upper cylindrical section cylinder.

2. The microbubble-assisted microplastic cyclonic separation device of claim 1, wherein, The micro-bubble generating assembly comprises: an aeration disc, a hollow connecting support and a gas supply pipeline; one end of the hollow connecting support is connected to the aeration disc, and the other end of the hollow connecting support is connected to the inner wall of the lower conical section cylinder; the gas supply pipeline is arranged in the hollow connecting support; one end of the gas supply pipeline is connected to the aeration disc, and the other end of the gas supply pipeline is connected to a gas pump from the inner wall of the lower conical section cylinder.

3. The microbubble-assisted microplastic cyclonic separation device of claim 2, wherein, The micro-bubble generating assembly further comprises: a pressure regulating valve and a flow meter; both the pressure regulating valve and the flow meter are arranged in the gas supply pipeline.

4. The microbubble-assisted microplastic cyclonic separation device of claim 1, wherein, The ultrasonic vibration assembly comprises: an ultrasonic transducer, a conducting plate and a clamp; the ultrasonic vibration output end of the ultrasonic transducer is connected to the conducting plate, and the conducting plate is in contact with the outer wall of the upper cylindrical section cylinder; the ultrasonic transducer is fastened to the upper cylindrical section cylinder by the clamp.

5. The microbubble-assisted microplastic cyclonic separation device of claim 1, wherein, The electric field induction assembly comprises: an upper electrode ring, a lower electrode ring, an upper hollow support and a lower hollow support; one end of the upper hollow support is connected to the upper electrode ring, and the other end of the upper hollow support is connected to the inner wall of the upper cylindrical section cylinder; one end of the lower hollow support is connected to the lower electrode ring, and the other end of the lower hollow support is connected to the inner wall of the upper cylindrical section cylinder; there are electric wires in the upper hollow support and the lower hollow support; one end of the electric wires is connected to the upper electrode ring and the lower electrode ring respectively, and the other end of the electric wires is connected to a power supply from the inner wall of the upper cylindrical section cylinder, so that the upper electrode ring is positively charged and the lower electrode ring is negatively charged.

6. The microbubble-assisted microplastic cyclonic separation device of claim 5, wherein, The upper electrode ring, the lower electrode ring, the upper hollow support and the lower hollow support are all covered with a polytetrafluoroethylene or epoxy resin insulation layer.

7. The microbubble-assisted microplastic cyclonic separation device of claim 1, wherein, A guide plate is hinged to the water outlet end of the tangential water inlet pipe.

8. The microbubble-assisted based microplastic cyclonic separation device as claimed in claim 1, wherein, It further comprises: A guide cylinder and a fastening bolt; the middle clear water outlet pipe is connected to the upper cylindrical section cylinder from the guide cylinder; a through hole is formed in the side wall of the guide cylinder; the fastening bolt extends into the through hole to fasten the middle clear water outlet pipe.

9. The microbubble-assisted microplastic cyclonic separation device according to claim 1 or 8, wherein, The water inlet end of the middle clear water outlet pipe is of a bending structure.

10. The microbubble-assisted microplastic cyclonic separation device of claim 1, wherein, The top of the upper cylindrical section cylinder has a threaded through hole, the top overflow pipe has an external thread, and the external thread and the threaded through hole are connected through threads.

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