Micro-nano air flotation filtration structure and micro-nano air flotation filtration device

Abstract

The present invention provides a micro-nano air flotation filtration structure and a micro-nano air flotation filtration device, the micro-nano air flotation filtration structure comprises a housing chamber, a rotation drive unit and a membrane filtration unit, the membrane filtration unit is arranged in the housing chamber, the rotation drive unit is arranged outside the housing chamber, the rotation drive unit drives the membrane filtration unit to rotate, the membrane filtration unit comprises a hollow rotating shaft and a filter membrane, a seepage channel is arranged in the hollow rotating shaft, the filter membranes are all arranged on the hollow rotating shaft, a water production channel is arranged in the filter membrane, the water production channel is connected with the seepage channel, an air flotation aeration unit is arranged in the housing chamber, the air flotation aeration unit is arranged below the filter membrane, and the air flotation aeration unit can discharge micro-nano bubbles; the micro-nano air flotation filtration device comprises the above-mentioned micro-nano air flotation filtration structure. The present invention can reduce the sediment on the membrane surface and improve the filtration efficiency and stability.

Description

Technical Field

[0001] The invention relates to the technical field of membrane filtration, and in particular to a micro-nano air flotation filtration structure and a micro-nano air flotation filtration device. Background Art

[0002] Cross-flow filtration is a form of "cross-flow filtration" in which the liquid flow direction is tangential to the filter membrane. Due to its high surface cross-flow, the shear force on the membrane surface is increased, which has a certain flushing effect on the membrane surface, so that the filtration process can always work under the condition of accumulating a small amount of filter cake, which improves the concentration polarization and membrane pollution in the membrane separation process to a certain extent. However, as the filtration time increases, affected by factors such as liquid reflux resistance, the tangential flow velocity generated by the fluid on the membrane surface is insufficient to completely flush away the sediment layer on the filter membrane surface over time. With the deepening of theoretical and experimental research related to membrane separation methods, the cross-flow filtration method is optimized to obtain dynamic cross-flow filtration, which uses the centrifugal force, shear force and turbulent flow of the feed liquid generated by the rotation of the fluid to make the feed liquid produce a higher tangential flow velocity on the membrane surface, thereby inhibiting the growth of the filter cake layer, which can more effectively eliminate membrane surface pollution, reduce concentration polarization, and increase the stability of membrane system filtration.

[0003] However, in some fields such as biopharmaceuticals, preparation of new nanomaterials, sewage treatment, etc., the materials have high viscosity, high impurity content, and relatively high solid content. This can easily cause the membrane filtration device to reach a pollution level in a relatively short period of time, resulting in decreased filtration efficiency, poor filtration stability, and relatively low concentration.

[0004] There is a rotary ceramic membrane filtration device in the prior art, which is usually implemented by using a regular disc diaphragm, which is fixed on a hollow rotating shaft. This method is more convenient for mechanical fixing and installation of the circular diaphragm, but it will cause the feed liquid to tend to be orderly in the flow field and the particles to gradually deposit on the membrane surface, which will lead to a decrease in the anti-pollution ability of the diaphragm during the separation process, thereby limiting the application field of this type of rotary membrane filtration system. Summary of the invention

[0005] The first object of the present invention is to provide a micro-nano air flotation filtration structure which can reduce the sediment on the membrane surface and improve the filtration efficiency and stability.

[0006] The second object of the present invention is to provide a micro-nano air flotation filtration device comprising the above-mentioned micro-nano air flotation filtration structure.

[0007] In order to achieve the above-mentioned first purpose, the present invention provides a micro-nano flotation filtration structure, including a accommodating chamber, a rotation drive unit and a membrane filtration unit, the membrane filtration unit is arranged in the accommodating chamber, the rotation drive unit is arranged outside the accommodating chamber, the rotation drive unit drives the membrane filtration unit to rotate, the membrane filtration unit includes a hollow rotating shaft and a filter membrane, a seepage channel is arranged in the hollow rotating shaft, the filter membranes are all arranged on the hollow rotating shaft, a water production channel is arranged in the filter membrane, the water production channel is connected to the seepage channel, and an air flotation aeration unit is also arranged in the accommodating chamber, the air flotation aeration unit is arranged below the filter membrane, and the air flotation aeration unit can discharge micro-nano bubbles.

[0008] It can be seen from the above scheme that when the rotary drive unit drives the membrane filter unit to rotate, the fluid in the accommodating chamber will generate disordered turbulence. A large number of micro-nano bubbles are discharged by setting up an air flotation aeration unit, and under the coordinated action of the rotating centrifugal force and shear force, the micro-nano bubbles will explode and form vortices, which is beneficial to enhancing the disorder of the turbulence, thereby effectively reducing the deposition of particles on the surface of the filter membrane and delaying the surface pollution of the filter membrane, so that it can be more adaptable to the material environment with high concentration, high solid content and high viscosity, and greatly improve the separation and filtration efficiency and performance of the rotating membrane; during the rising process, the micro-nano bubbles adhere to the pollutants or particles in the fluid, so that the buoyancy of the pollutants or particles is greater than the gravity and the floating resistance, so that the pollutants or particles float up, which is beneficial to reduce the deposition of pollutants or particles on the surface of the filter membrane, sweep the surface of the filter membrane, weaken the concentration polarization, and reduce membrane pollution.

[0009] A further solution is that the air flotation aeration unit is configured as an air flotation membrane, the air flotation membrane is disposed on a hollow rotating shaft and is located directly below the filter membrane, and the air flotation membrane can rotate along with the hollow rotating shaft.

[0010] It can be seen from the above scheme that by arranging the air floating membrane on the hollow rotating shaft, when the hollow rotating shaft rotates, the air floating membrane and the filter membrane rotate synchronously, and the two are in a relatively static state, so that the bubbles emitted by the air floating membrane can act on the surface of the filter membrane, which is beneficial to reduce the pollution of the filter membrane surface.

[0011] A further solution is that the air flotation membrane is provided with a first air inlet channel and a plurality of air outlet micropores, the first air inlet channel is connected to the plurality of air outlet micropores respectively; a second air inlet channel is also provided in the hollow rotating shaft, the second air inlet channel is connected to the first air inlet channel.

[0012] It can be seen from the above scheme that by arranging a second air inlet channel in the hollow rotating shaft to ventilate the interior of the air floating membrane, the air floating membrane can discharge micro-nano bubbles outward while rotating.

[0013] A further solution is that a cross-flow channel is formed between the filter membrane and the air flotation membrane, and the cross-flow channel is communicated with the accommodating cavity.

[0014] It can be seen from the above scheme that by setting up the cross-flow channel, on the one hand, it is convenient for the fluid to filter into the filter membrane from the cross-flow channel, and on the other hand, it is convenient for the micro-nano bubbles to act on the fluid in the cross-flow channel and sweep the filter membrane surface.

[0015] A further solution is that a plurality of filter membranes are provided, a plurality of air-floating membranes are provided, the air-floating membranes and the filter membranes are arranged vertically and spaced apart, and the air-floating membranes and the filter membranes are arranged in parallel.

[0016] It can be seen from the above scheme that multiple filter membranes and multiple air floating membranes are arranged at intervals, so that there is at least one air floating membrane under each filter membrane, ensuring that each filter membrane can be affected by the micro-nano bubbles discharged by the air floating membrane.

[0017] A further solution is that the filter membrane and the air flotation membrane are both detachably connected to the hollow rotating shaft, and the filter membrane and the air flotation membrane can exchange installation positions. After the two exchange positions, the second air inlet channel is connected to the water production channel of the filter membrane.

[0018] It can be seen from the above scheme that when necessary, the filter membrane can be installed in an exchange position with the air flotation membrane, and the filter membrane can be cleaned by gas to achieve online active cleaning, which is beneficial to further reduce pollutants on the filter membrane surface and ensure the continuity and stability of the system operation.

[0019] A further solution is that the air flotation aeration unit is arranged on the bottom wall of the accommodating cavity, and the hollow rotating shaft can rotate relative to the air flotation aeration unit.

[0020] It can be seen from the above solution that by arranging the air flotation aeration unit on the bottom wall of the accommodating cavity, the micro-nano bubbles of the air flotation aeration unit can act on all the filter membranes thereon, which is beneficial to saving the function of the air flotation aeration unit.

[0021] In order to achieve the above-mentioned second purpose, the present invention provides a micro-nano flotation filtration device, including a mounting bracket, a separation tank and the above-mentioned micro-nano flotation filtration structure, the separation tank is arranged on the mounting bracket, the membrane filtration unit and the flotation aeration unit of the micro-nano flotation filtration structure are both arranged in the separation tank, and the rotation drive unit of the micro-nano flotation filtration structure is arranged outside the separation tank.

[0022] A further solution is that one end of the hollow rotating shaft of the membrane filtration unit passes through the separation tank, and the hollow rotating shaft is provided with a permeate outlet at the end passing through the separation tank, and the permeate outlet is connected to the permeate channel of the hollow rotating shaft.

[0023] A further solution is that a liquid inlet pipe and a sewage discharge pipe are provided at the lower part of the separation tank, a liquid discharge pipe is provided at the upper part of the separation tank, and pressure detectors are provided at the liquid inlet pipe, the sewage discharge pipe and the upper part of the separation tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of an embodiment of a micro-nano flotation filtration device of the present invention.

[0025] Figure 2 It is a structural diagram of the micro-nano air flotation filtration structure in the embodiment of the micro-nano air flotation filtration device of the present invention.

[0026] Figure 3 It is a cross-sectional view of a membrane filtration unit and an air flotation aeration unit in an embodiment of a micro-nano air flotation filtration device of the present invention.

[0027] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0028] See also Figures 1 to 3 The micro-nano flotation filtration device provided in this embodiment includes a mounting bracket 1, a separation tank 2 and a micro-nano flotation filtration structure. The separation tank 2 is arranged on the mounting bracket 1, and a receiving chamber is arranged in the separation tank 2. The micro-nano flotation filtration structure includes a rotation drive unit 3, a membrane filtration unit 4 and an air flotation aeration unit. The membrane filtration unit 4 and the air flotation aeration unit are both arranged in the receiving chamber of the separation tank 2. The rotation drive unit 3 is arranged on the lower outer side of the separation tank 2 and on the mounting bracket 1. The rotation drive unit 3 can drive the membrane filtration unit 4 to rotate. During the rotation process of the membrane filtration unit 4, the fluid in the receiving chamber will generate disordered turbulence. The air flotation aeration unit can discharge a large number of micro-nano bubbles to increase the disorder degree of the disordered turbulence, thereby increasing the flow of the fluid and the turbulent disturbance.

[0029] The membrane filtration unit 4 includes a hollow rotating shaft 41 and a plurality of filter membranes 42. The upper portion of the hollow rotating shaft 41 is arranged in the separation tank 2, and the lower portion of the hollow rotating shaft 41 passes through the separation tank 2. The hollow rotating shaft 41 is sealed and connected with the separation tank 2 by a mechanical seal assembly, and the mechanical seal assembly is a standard accessory in this field, which will not be repeated here. The rotation drive unit 3 includes a drive motor and a reducer, and the drive motor is preferably an asynchronous motor. The drive shaft of the drive motor is connected to the reducer, and the reducer adopts a parallel shaft reducer, and the reducer is connected to the lower portion of the hollow rotating shaft 41 through a hollow shaft locking device. A seepage channel 411 is provided in the hollow rotating shaft 41, and the seepage channel 411 extends axially along the hollow rotating shaft 41, and the seepage channel 411 is provided with a permeate outlet 412 at one end passing through the separation tank 2, and the seepage outlet is communicated with the seepage channel 411.

[0030] The plurality of filter membranes 42 are divided into two or three groups of equal number, and each group is evenly spaced and arranged on the hollow rotating shaft 41. In this embodiment, two groups of three filter membranes 42 are arranged as an example. The extension direction of the filter membrane 42 is perpendicular to the axial direction of the hollow rotating shaft 41. The interval between two adjacent filter membranes 42 in the same group is a preset distance, and the filter membrane 42 is fixed by a stacking plate 43. The top filter membrane 42 is fastened by an upper limit member 44, and the filter membrane 42 is sealed with the upper limit member 44 and the stacking plate 43. All filter membranes 42 are arranged in parallel, and a water production channel 421 is arranged in the filter membrane 42. A plurality of filter holes are arranged on the surface of the filter membrane 42, and the filter holes are connected with the permeate channel 411 through the water production channel 421. The membrane filtration unit 4 and the hollow rotating shaft 41 rotate under the drive of the rotary drive unit 3, which can form a disordered turbulent phenomenon inconsistent with the filtration direction, and can avoid the deposition of particles on the membrane surface to reduce membrane pollution.

[0031] The filter membrane 42 is set to a disc structure or a disc structure, and the disc filter membrane 42 has the advantages of stable structure, fast rotation speed and good separation effect. The filter membrane 42 is mainly a porous membrane prepared from inorganic materials such as A12O3, ZrO2, TiO2 and SiO2, and its pore size is 0.01μm to 50μm, which can adapt to the operating environment of higher rotation speeds such as 300-1000RPM. The filter membrane 42 can be a hollow ceramic membrane, a PVDF membrane, a metal membrane or a film membrane, wherein the metal membrane and the film membrane are suitable for the operating environment of a lower rotation speed. PVDF membrane, i.e., polyvinylidene fluoride membrane, is a solid support commonly used in protein blotting. The film membrane is preferably an IPUF film membrane sold on the market.

[0032] The air flotation aeration unit is arranged below the filter membrane 42, and the air flotation aeration unit can discharge a large number of micro-nano bubbles. The tiny bubbles existing in the liquid are called micron bubbles when the bubble diameter is below 100 μm, and the bubbles with a diameter of below 100 nm are called nano bubbles. Micro-nano bubbles refer to bubbles with a diameter between tens of microns and hundreds of nanometers when the bubbles occur. This type of bubble is between micron bubbles and nano bubbles, and has physical and chemical properties that conventional bubbles do not have, such as air flotation function. The air flotation function refers to passing bubbles into a liquid mixed with other phases or particles, and utilizing the adsorption of the bubbles due to the negative charge on the outside of the bubbles. During the concentration and separation process of the fluid, the other phases or particles in the fluid themselves carry positive charges, and the positive and negative charges attract each other, so that the bubbles are adsorbed on the surface of other phases or particles, thereby increasing the buoyancy of other phases or particles in the liquid, making them float on the surface of the liquid, and achieving the purpose of separation from the liquid. Therefore, the better the adsorption performance of the bubble, the better the air flotation effect, and the adsorption performance of the bubble depends on the size of its diameter. The smaller the diameter of the bubble, the higher the potential on its surface, so it is easier for it to adsorb on the surface of other phases in the liquid, causing it to separate from the liquid.

[0033] In one embodiment, the air flotation aeration unit is set as an air flotation membrane 5, the number of air flotation membranes 5 is set to multiple, the air flotation membrane 5 is set on the hollow rotating shaft 41, the air flotation membrane 5 is parallel to the filter membrane 42 and arranged at intervals, and the air flotation membrane 5 is set below the filter membrane 42, and the air flotation membrane 5 located at the bottom is fastened by the lower limit member 45. When the hollow rotating shaft 41 drives the filter membrane 42 to rotate, the air flotation membrane 5 follows the synchronous rotation, and the micro-nano bubbles are evenly dispersed into the separation tank 2, so as to give full play to the vortex effect of the micro-nano bubble explosion and increase the flow disorder of the fluid. The air flotation membrane 5 is connected to the first air inlet channel 51 and multiple air outlet micropores. In this embodiment, the aperture of the air outlet micropore is nanometer-level, and the bubbles generated are nanobubbles, which have the characteristics of the above-mentioned micro-nano bubbles, have more efficient filtration and separation efficiency, and are more adaptable to the separation scene of high viscosity and high solid content materials.

[0034] Correspondingly, a second air inlet channel 413 is also provided in the hollow rotating shaft 41, and the second air inlet channel 413 extends along the axial direction of the hollow rotating shaft 41, and the second air inlet channel 413 is connected to the first air inlet channel 51, and the second air inlet channel 413 is connected to the air supply device outside the separation tank 2 through the air pipe 7, and the air pipe 7 preferably passes upward through the upper cover 22 of the separation tank 2. Compressed gas is blown into the air floating membrane 5 through the external air supply device, so that the air floating membrane 5 discharges a large number of micro-nano bubbles into the accommodating cavity.

[0035] A cross-flow channel 6 for fluid to flow through is provided between the filter membrane 42 and the adjacent air-floating membrane 5. The cross-flow channel 6 is connected to the accommodating chamber. When rotating, the air-floating disturbance and bubble burst of the air-floating membrane 5 form vortices, which can form disordered turbulence that is inconsistent with the filtering direction. The fluid is simultaneously subjected to forces in several different directions in the cross-flow channel 6, forming a more disordered disordered turbulence, which can effectively wipe the surface of the filter membrane 42, weaken concentration polarization, and reduce membrane pollution. The setting of the air-floating membrane 5 utilizes cloud flotation to form local vortices and strengthen the turbulence on the membrane surface, thereby effectively avoiding the deposition of particles on the surface of the filter membrane 42, greatly reducing membrane pollution, and being able to maintain continuity and stability, making it more suitable for the filtration and separation of high-viscosity and high-solid-content material systems.

[0036] In this embodiment, an air flotation membrane 5 is arranged between two adjacent filter membranes 42. In other embodiments, the number of air flotation membranes 5 can be adjusted according to the characteristics of the material. For example, when concentrating the zirconium oxide nanopowder slurry, due to its low viscosity but high solid content, the air flotation membrane 5 can be arranged between two filter membranes 42, that is, two filter membranes 42 are arranged between two adjacent air flotation membranes 5. Such an arrangement can ensure the stability of the permeation flux of the system.

[0037] In this embodiment, the filter membrane 42 and the air-floating membrane 5 are both detachably connected to the hollow rotating shaft 41, and the filter membrane 42 and the air-floating membrane 5 have the same structure, that is, the filter membrane 42 and the air-floating membrane 5 can be the same membrane, but the functions of the two are different, and the filter membrane 42 and the air-floating membrane 5 can be exchanged in installation position. Within a certain period of time, the installation positions of the filter membrane 42 and the air-floating membrane 5 can be exchanged; when the installation positions of the two are exchanged, the external air supply device supplies air to the inside of the filter membrane 42 through the second air inlet channel 413, and the gas is discharged from the filter hole of the filter membrane 42, which plays the role of cleaning the filter membrane 42.

[0038] In another embodiment, the flotation aeration unit is fixedly arranged on the bottom wall of the accommodating cavity, and the hollow rotating shaft 41 can rotate relative to the flotation membrane 5. The flotation aeration unit of this embodiment can be a micro-nano bubble generator or a jet aerator, and the micro-nano bubble generator is connected to an external air supply device.

[0039] exist Figure 2 In the figure, the separation tank 2 includes a tank body 21 and an upper cover 22, the upper cover 22 is provided with a compression bolt (not shown in the figure), the upper cover 22 is fastened to the tank body 21 by the compression bolt, and the upper cover 22 is sealed and connected to the upper part of the tank body 21 by a sealing ring. A drain pipe 23 is provided on the top of the upper cover 22, the drain pipe 23 is connected to the inside of the tank body 21, and the drain pipe 23 also has an exhaust function. The tank body 21 is provided with an inlet pipe 24 and a sewage pipe 25 at its bottom, the inlet pipe 24 and the sewage pipe 25 are respectively arranged on the left and right sides of the separation tank 2, and the inlet pipe 24 and the sewage pipe 23 are preferably arranged diagonally. The inlet pipe 24 of the separation tank 2 is connected to an infusion pump, and the feed liquid is transported into the separation tank 2 by the infusion pump, the permeate enters the inside of the filter membrane 42 and is discharged from the permeate outlet 412 through the permeate channel, and the intercepted concentrated liquid remains outside the filter membrane 42 and is discharged through the drain pipe 23. The liquid inlet pipe 24 and the sewage discharge pipe 25 are respectively provided with pressure detectors, and the upper part of the separation tank 2 is also provided with a pressure detector.

[0040] The present embodiment may also be provided with a speed regulating unit, which adjusts the rotation speed of the membrane filtration unit 4 to meet the requirements of processing materials with different viscosities, solid contents and other characteristics, and can process sewage of different degrees, with a wide range of applications.

[0041] The device of this embodiment has a compact structure, small external dimensions, and low production cost, and can be applied to most production enterprises or sewage treatment enterprises to meet the treatment requirements of different types of materials or sewage, and has obvious and considerable economic benefits.

[0042] Tooling process: The driving motor drives the hollow rotating shaft 41 to rotate through the reducer, and then drives all the filter membranes 42 to rotate. The liquid inlet pipe 24 of the separation tank 2 is installed with an infusion pump, which delivers the feed liquid into the tank body 21, and the concentrated liquid is discharged through the discharge pipe 23. Due to the pressure difference between the inside and outside of the tank body 21 caused by the infusion pump or the permeate negative pressure suction pump, the filtered permeate is pressed into the water production channel 421 and the inside of the hollow rotating shaft 41 through the filter holes of the filter membrane 42, and finally discharged through the permeate outlet 412. During this period, the external air supply device is turned on and compressed air is delivered to the air flotation aeration unit, so that the air flotation aeration unit discharges a large number of micro-nano bubbles into the fluid in the separation tank 2, performs air flotation turbulence disturbance on the fluid, and promotes sufficient turbulence of the fluid in the separation tank 2.

[0043] In summary, when the rotary drive unit of the present invention drives the membrane filter unit to rotate, the fluid in the accommodating chamber will generate disordered turbulence. A large number of micro-nano bubbles are discharged by setting up the air flotation aeration unit, and under the coordinated action of the rotating centrifugal force and the shear force, the micro-nano bubbles will explode and form vortices, which is beneficial to enhancing the disorder of the turbulence; during the rising process, the micro-nano bubbles adhere to the pollutants or particulate matter in the fluid, so that the buoyancy of the pollutants or particulate matter is greater than the gravity and the floating resistance, so that the pollutants or particulate matter floats, which is beneficial to reduce the deposition of pollutants or particulate matter on the surface of the filter membrane, sweep the surface of the filter membrane, weaken the concentration polarization, and reduce membrane pollution.

[0044] Finally, it should be emphasized that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A micro-nano air flotation filtration structure, comprising a housing chamber, a rotation drive unit and a membrane filtration unit, wherein the membrane filtration unit is arranged in the housing chamber, the rotation drive unit is arranged outside the housing chamber, the rotation drive unit drives the membrane filtration unit to rotate, the membrane filtration unit comprises a hollow rotating shaft and a filter membrane, a liquid seepage channel is arranged in the hollow rotating shaft, the filter membranes are all arranged on the hollow rotating shaft, a water production channel is arranged in the filter membrane, the water production channel is connected to the liquid seepage channel, and the characteristics are as follows: The accommodating chamber is also provided with an air flotation aeration unit, which is arranged below the filter membrane and can discharge micro-nano bubbles; The air flotation aeration unit is configured as an air flotation membrane, which is disposed on the hollow rotating shaft and is located directly below the filter membrane, and the air flotation membrane can rotate along with the hollow rotating shaft; The air floating membrane is provided with a first air inlet channel and a plurality of air outlet micropores, and the first air inlet channel is communicated with the plurality of air outlet micropores respectively; A second air inlet passage is also provided in the hollow rotating shaft, and the second air inlet passage is communicated with the first air inlet passage; A cross-flow channel is formed between the filter membrane and the air-floating membrane, and the cross-flow channel is communicated with the accommodating cavity; There are a plurality of filter membranes, there are a plurality of air-floating membranes, the air-floating membranes and the filter membranes are arranged vertically and spaced apart, and the air-floating membranes and the filter membranes are arranged in parallel.

2. The micro-nano air flotation filtration structure according to claim 1, characterized in that: The filter membrane and the air floating membrane are both detachably connected to the hollow rotating shaft, and the filter membrane and the air floating membrane can exchange installation positions. After the two exchange positions, the second air inlet channel is connected to the water production channel of the filter membrane.

3. The micro-nano air flotation filtration structure according to claim 1, characterized in that: The air flotation aeration unit is arranged on the bottom wall of the accommodating chamber, and the hollow rotating shaft can rotate relative to the air flotation aeration unit.

4. Micro-nano air flotation filtration device, characterized by: It comprises a mounting bracket, a separation tank and the micro-nano flotation filtration structure according to any one of claims 1 to 3, wherein the separation tank is arranged on the mounting bracket, the membrane filtration unit and the flotation aeration unit of the micro-nano flotation filtration structure are both arranged in the separation tank, and the rotation drive unit of the micro-nano flotation filtration structure is arranged outside the separation tank.

5. The micro-nano air flotation filtration device according to claim 4, characterized in that: One end of the hollow rotating shaft of the membrane filtration unit passes through the separation tank, and the hollow rotating shaft is provided with a permeate outlet at the end passing through the separation tank, and the permeate outlet is communicated with the permeate channel of the hollow rotating shaft.

6. The micro-nano air flotation filtration device according to claim 5, characterized in that: The lower part of the separation tank is provided with a liquid inlet pipe and a sewage discharge pipe, the upper part of the separation tank is provided with a liquid discharge pipe, and the liquid inlet pipe, the sewage discharge pipe and the upper part of the separation tank are all provided with pressure detectors.

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