Water purification device and method for removing micro-plastics

Abstract

The invention discloses a water purification device and method for removing microplastics, and belongs to the technical field of water treatment. The water purification device for removing the micro-plastics comprises an electrochemical adsorption oxidation unit and a self-cleaning desorption unit, the electrochemical adsorption oxidation unit comprises a cylinder, a cathode, a filter screen, an anode, a three-dimensional particle electrode and a supporting layer; a sewage inlet for sewage containing micro-plastics to enter the electrochemical adsorption oxidation unit is formed in the bottom of the side surface of the barrel; the cathode is sleeved in the cylinder and is a cylindrical stainless steel mesh electrode, and the bottom of the cathode is separated from the inner wall of the bottom of the cylinder; the bottom of the filter screen is connected with the inner wall of the bottom of the barrel; the anode is positioned in the cylinder; the three-dimensional particle electrode is arranged between the filter screen and the anode; the bottom of the supporting layer is provided with an opening with the aperture smaller than the diameter of the three-dimensional particle electrode. The method is applied to removal of the micro-plastics in the water, realizes efficient removal of the micro-plastics in the water without adding extra chemical agents, and has the characteristic of being recyclable.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and in particular relates to a water purification device and method for removing microplastics. Background Art

[0002] In recent years, microplastic pollution has attracted increasing public attention and has evolved into a global environmental problem. There is evidence that microplastics may exist stably in aquatic environments for thousands of years due to their chemical stability. As an emerging pollutant, they have caused serious economic losses to marine ecosystems. Due to their large specific surface area, persistence and fluidity, microplastics are more likely to adsorb organic chemical pollutants, heavy metals and harmful bacteria, resulting in an increasing impact of microplastics on the aquatic environment and increasing harm to human health. In particular, due to their light density and small size, microplastics are easily ingested by aquatic organisms after entering the water body, causing intestinal wear and blockage. Toxic chemicals attached to plastic particles are also very harmful to aquatic organisms and are eventually transmitted to humans through the food chain, causing serious health problems. However, due to the small size of microplastics and their low concentration in polluted water, it is an ongoing challenge to effectively separate them.

[0003] Researchers have tried to study different technologies for removing microplastics from water. Physical removal methods include adsorption, filtration, membrane separation, centrifugal separation, flotation, sol-gel separation, magnetic separation, electrocoagulation, etc. Existing physical removal technologies for microplastic treatment mainly include adsorption, coagulation, filtration and magnetic separation, which can be used to remove microplastics from polluted streams. Among them, the biochar filter integrates biochar into the sand filtration system, which has a strong ability to remove and fix microplastic spheres. It is combined with magnetic seed filtration to separate finer polymer microplastic particles from dilute suspensions with relatively high efficiency; membrane separation can remove micro / nano plastics from wastewater, and microplastics can be effectively removed from sewage by interception. However, efficient removal / separation of microplastics remains challenging because they are small in size and have low concentrations in polluted water. Moreover, most of these methods rely mainly on chemical flocculation and filtration, which are costly, and the filler and membrane pollution are difficult to recycle and regenerate, resulting in excess energy for long-term operation and maintenance.

[0004] In addition, there are biological and chemical methods, such as photocatalysis, chemical digestion, microbial decomposition, etc. Biological removal methods are environmentally friendly, but the removal of microplastics is slow. Chemical removal methods are relatively expensive and may cause secondary pollution. Summary of the invention

[0005] The details of one or more embodiments of the present invention are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent.

[0006] The present invention proposes a water purification device and method for removing microplastics, which solves at least one of the above-mentioned technical problems existing in existing microplastic removal methods, achieves efficient removal of microplastics in water without the need for additional chemical agents, and has the characteristic of being renewable.

[0007] On one hand, the present invention discloses a water purification device for removing microplastics, which is used for removing microplastics in water, and comprises an electrochemical adsorption oxidation unit and a self-cleaning desorption unit; The electrochemical adsorption oxidation unit comprises: a cylinder, a cathode, a filter, an anode, a three-dimensional particle electrode, and a supporting layer for supporting the three-dimensional particle electrode; a sewage inlet for sewage containing microplastics to enter the electrochemical adsorption oxidation unit is provided at the bottom of the side of the cylinder; the cathode is sleeved in the cylinder and is a cylindrical stainless steel mesh electrode, and the bottom is spaced from the inner wall of the bottom of the cylinder; the filter is sleeved in the cathode, and the bottom is connected to the inner wall of the bottom of the cylinder; the anode is located in the middle of the cylinder; the three-dimensional particle electrode is provided between the filter and the anode; the bottom of the supporting layer is provided with an opening whose aperture is smaller than the diameter of the three-dimensional particle electrode; The self-cleaning desorption unit is arranged at the top of the cylinder, including a desorption shell and a water outlet pipe; the desorption shell is an inverted cone, which rotates under the drive of the driving member, with the top opening to allow the three-dimensional particle electrode to enter the shell for centrifugation, and the bottom opening to allow the three-dimensional particle electrode to return to the electrochemical adsorption oxidation unit after desorption; the water outlet pipe is arranged in the shell and coincides with the central axis of the shell, and the bottom opening is to discharge the desorbed microplastics.

[0008] In some of the embodiments, the top of the cylinder is open to allow water for removing microplastics to flow out of the cylinder; the bottom of the cylinder is provided with a flushing inlet for flushing the three-dimensional particle electrode adsorbed with microplastics from the electrochemical adsorption oxidation unit into the desorption shell; the bottom of the anode is flush with the bottom of the cathode, and the bottom of the supporting layer is flush with the bottom of the cathode.

[0009] In some embodiments, the outer side surface of the filter screen and the inner wall of the cylinder define a sludge channel, and the bottom of the side surface of the cylinder is provided with a sludge discharge port connected to the sludge channel.

[0010] In some embodiments, the supporting layer includes a first supporting layer located at the bottom, and a plurality of second supporting layers spaced apart from the first supporting layer, located above the first supporting layer and spaced apart from each other; the first supporting layer is provided with openings having an aperture smaller than the diameter of the three-dimensional granular electrode, and the second supporting layer is provided with openings having an aperture larger than the diameter of the three-dimensional granular electrode.

[0011] In some embodiments, the distance between the second supporting layer and the first supporting layer, and the distance between each second supporting layer are greater than the diameter of the three-dimensional particle electrode and less than twice the diameter of the three-dimensional particle electrode.

[0012] In some embodiments, the distance between the cathode and the anode is 10-20 cm; the cathode is made of ruthenium, iridium, or aluminum; the anode is a titanium filter electrode with a pore size of 0.1-1 mm; and the three-dimensional granular electrode is a granular three-dimensional electrode made by oxidation of carbon black coupled iron.

[0013] In some of the embodiments, the anode is a titanium filter electrode oxidized at 350°C in a muffle furnace; the three-dimensional granular electrode is a granular electrode oxidized at 200°C by coupling carbon black, phenolic resin and iron powder, wherein the carbon black accounts for 90-98%, the phenolic resin accounts for 1-5%, the iron powder accounts for 1-5%, and the particle size of the three-dimensional granular electrode is 1-5 mm.

[0014] In some of the embodiments, the self-cleaning desorption unit further includes a desorption cover arranged corresponding to the bottom opening of the desorption shell, and the desorption cover is conical.

[0015] In some of the embodiments, the self-cleaning desorption unit is connected to the anode; the desorption shell is made of stainless steel and is provided with a cyclone gallery inside, and the inner diameter of the gallery is 5-15 mm; the inner diameter of the water outlet pipe is 0.5-4.5 mm.

[0016] Another aspect of the present invention discloses a method for removing microplastics from water by using a water purification device for removing microplastics as described in any of the above technical solutions, comprising the following steps: The water to be treated flows into the cathode from the sewage inlet, and the cathode produces alkali through the action of electrolyzed water. The calcium and magnesium ions contained in the raw water combine with the alkali produced by the cathode to precipitate. After cathode pretreatment, the large suspended particles are separated by the filter. The water filtered by the filter is passed into the three-dimensional particle electrode. The microplastic particles in the water are adsorbed on the three-dimensional particle electrode through the positive and negative charges induced by the three-dimensional particle electrode, and advanced oxidation occurs on the surface of the three-dimensional particle electrode to achieve the degradation of microplastics. After being treated by the three-dimensional particle electrode, they gather near the anode, and are further filtered and oxidized by the anode, and the treated water flows out of the anode filter element through the water outlet; When the microplastics and other impurities on the three-dimensional particle electrode increase and block the flow of water, a disturbance is generated to disturb the three-dimensional particle electrode and float it. The electrochemical adsorption oxidation unit is closed and the self-cleaning desorption unit is turned on. The three-dimensional particle electrode is flushed to the top under the action of flushing water and enters the desorption shell. The three-dimensional particle electrode is subjected to centrifugal flow in the desorption shell. The microplastics and impurities on the three-dimensional particle electrode are thrown out by centrifugal action and discharged from the outlet pipe with the water flow. The three-dimensional particle electrode returns to the supporting layer from the bottom opening of the desorption shell to complete self-cleaning.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a water purification device for removing microplastics. The device uses the electrosorption and in-situ advanced oxidation of the induced three-dimensional particles of iron-coupled carbon black sandwiched between the anode and the cathode, combined with the deep filtration and oxidation of the titanium filter element anode to efficiently remove microplastics in the water. In conjunction with a self-cleaning system, the device uses the water washing and flotation coupled cyclonic centrifugation to desorb the microplastics adsorbed by the used three-dimensional particles, thereby achieving the regeneration of the three-dimensional particles. The device achieves efficient removal of microplastics in the water without the need for additional chemical agents, and has the characteristic of material recyclability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 A schematic diagram of the structure of a water purification device for removing microplastics provided in an embodiment of the present invention; Figure 2 A schematic diagram of the structure of a self-cleaning desorption unit provided in an embodiment of the present invention; Description of the drawings: 101, cylinder; 102, cathode; 103, filter; 104, anode; 105, three-dimensional granular electrode; 1061, first supporting layer; 1062, second supporting layer; 201, desorption shell; 202, water outlet pipe; 203, outlet cover; 301, sewage inlet; 302, flushing water inlet; 303, mud outlet. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0020] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed by the present invention, some changes in design, manufacturing or production based on the technical content disclosed by the present invention are just conventional technical means, and should not be understood as insufficient content disclosed by the present invention.

[0021] Reference to "embodiments" in the present invention means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present invention may be combined with other embodiments without conflict.

[0022] Unless otherwise defined, the technical terms or scientific terms involved in the present invention shall have the usual meanings understood by persons with ordinary skills in the technical field to which the present invention belongs. The words "one", "a", "a", "the" and the like involved in the present invention do not indicate a quantity limitation and may indicate the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in the present invention are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device including a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in the present invention are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in the present invention refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, "A and / or B" may indicate: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects in the front and back relation are in an "or" relationship. The terms "first", "second", etc. involved in the present invention are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0023] The embodiment of the present invention provides a water purification device for removing microplastics. Figure 1 Schematic diagram of the structure of a water purification device for removing microplastics according to an embodiment of the present invention. Figure 1As shown, the water purification device for removing microplastics is used to remove microplastics in water, and at least includes: an electrochemical adsorption oxidation unit, and a self-cleaning desorption unit; The electrochemical adsorption oxidation unit comprises: a cylinder 101, a cathode 102, a filter 103, an anode 104, a three-dimensional particle electrode 105, and a supporting layer for supporting the three-dimensional particle electrode 105; a sewage inlet 301 for sewage containing microplastics to enter the electrochemical adsorption oxidation unit is provided at the bottom of the side of the cylinder 101; the cathode 102 is sleeved in the cylinder 101, and is a cylindrical stainless steel mesh electrode, and the bottom is separated from the inner wall of the bottom of the cylinder 101; the filter 103 is sleeved in the cathode 102, and the bottom is connected to the inner wall of the bottom of the cylinder 101; the anode 104 is located in the middle of the cylinder 101; the three-dimensional particle electrode 105 is arranged between the filter 103 and the anode 104; the bottom of the supporting layer is provided with an opening with a diameter smaller than the diameter of the three-dimensional particle electrode 105; like Figure 2 As shown, the self-cleaning desorption unit is arranged at the top of the cylinder 101, including a desorption shell 201 and a water outlet pipe 202; the desorption shell 201 is an inverted cone, which rotates under the drive of the driving member, with the top opening to allow the three-dimensional particle electrode 105 to enter the shell for centrifugation, and the bottom opening to allow the desorbed three-dimensional particle electrode 105 to return to the electrochemical adsorption oxidation unit; the water outlet pipe 202 is arranged in the shell and coincides with the central axis of the shell, and the bottom opening is to discharge the desorbed microplastics.

[0024] The electrochemical adsorption oxidation unit adopts a cylindrical double-barrel electrode coupled to an internal three-dimensional particle electrode 105 structure, with an outer cathode 102 and an inner anode 104; the raw water is intercepted by the cathode 102 through the in-situ alkali production effect combined with the filter 103 to intercept large plastic impurities such as calcium and magnesium, and the intercepted impurities are discharged from the mud outlet 303; the raw water entering the three-dimensional particle electrode 105 through radial flow generates positive and negative electricity on the particle surface due to the electric induction system of the anode and cathode 104, and the positive and negative electricity adsorbs the microplastics with positive or negative charges; the three-dimensional particle electrode 10 5 is made of carbon black with a rough surface and large porosity, which enhances the adsorption of microplastics. The iron in the three-dimensional electrode will produce hydroxyl radicals under the action of electrochemistry, and then the adsorbed microplastics will be gradually degraded and removed by advanced oxidation. By further limiting the diameter of the three-dimensional particle electrode 105, the microplastics of corresponding particle sizes can be effectively filtered and removed; a larger contact area can be obtained by entering the three-dimensional electrode particles through radial flow, thereby improving the removal effect of microplastics; the above-mentioned three-dimensional particle electrodes 105 are separated by a supporting layer, which effectively prevents the dispersion of particles.

[0025] After long-term operation, the system is backwashed by reversing the connection of the electrodes to achieve desorption of microplastics, and then rinsed with backwash water from the bottom. The particle electrode separates the particles from the microplastics through the self-cleaning desorption unit above, thereby achieving particle regeneration. Specifically, the self-cleaning desorption unit is turned on and controlled by the arrangement of the three-dimensional particle electrode 105 on the supporting layer. When the microplastics and other impurities on the three-dimensional particle electrode 105 increase and block the flow of water, a turbulent flow is generated to disturb the three-dimensional particle electrode 105 and float it, that is, the water inlet is closed and the self-cleaning desorption is turned on. After the self-cleaning desorption unit is turned on, the backwash water enters from the bottom backwash water inlet 302, and the water volume is evenly distributed through the bottom supporting layer to achieve a uniform backwash effect without dead ends. Under the action of the backwash water flow, the three-dimensional particle electrode 105 is separated from the support and washed to the top to enter the cyclone desorption device. Under the action of the cyclone rotation, the three-dimensional particle electrode 105 separates the microplastics and impurities on the surface of the three-dimensional particles through centrifugal action and mutual friction. The three-dimensional particles are discharged from the bottom of the cyclone desorption device due to their heavy weight, and the desorbed microplastics and impurities are discharged through the outlet pipe 202 along the wastewater outlet through the centrifugal action, thereby realizing the self-cleaning of the three-dimensional particles. When the three-dimensional particles are evenly distributed on the supporting layer and the incoming water no longer generates disturbances, the self-cleaning desorption system is stopped.

[0026] The above-mentioned water purification device for removing microplastics uses the electric adsorption and in-situ advanced oxidation of the induced three-dimensional particles of iron-coupled carbon black sandwiched between the anode and cathode 104, combined with the titanium filter anode 104 to deeply filter and oxidize the microplastics in the water body, and cooperates with the self-cleaning system. The microplastics adsorbed by the three-dimensional particles after use are desorbed by the action of water washing and floating coupling cyclone centrifugation, and the regeneration of the three-dimensional particles is realized. No additional chemical agent is required to achieve efficient removal of microplastics in the water body, and the material can be recycled. The above-mentioned device of the present invention treats sewage with very small microplastic volume and very low concentration, and realizes efficient removal of microplastics by filtering, adsorbing and coupling advanced oxidation; the process does not require the investment of additional agents, and the removal operation cost is low; the microplastics in the water body are positively / negatively charged, and the removal efficiency of microplastics is greatly enhanced by the induction electric field adsorption filtration and synchronous advanced oxidation; the three-dimensional particle induction electric field and surface adsorption performance are used to accelerate the removal of microplastics; the regeneration function of the system is realized through the cyclone backwashing effect; at the same time, large particles of microplastic waste are discharged through the bottom mud.

[0027] In some of the embodiments, the top of the cylinder 101 is open to allow water for removing microplastics to flow out of the cylinder 101; the bottom of the cylinder 101 is provided with a flushing water inlet 302 for flushing the three-dimensional particle electrode 105 adsorbed with microplastics from the electrochemical adsorption oxidation unit into the desorption shell 201; the bottom of the anode 104 is flush with the bottom of the cathode 102, and the bottom of the supporting layer is flush with the bottom of the cathode 102. By providing the flushing water inlet 302 at the bottom of the cylinder 101 and limiting the bottom of the supporting layer to be flush with the bottom of the cathode 102, a gap is formed between the supporting layer and the inner wall of the cylinder 101, which is conducive to making full use of the openings provided on the supporting layer to achieve uniform water distribution and achieve a uniform backwashing effect without dead corners.

[0028] In some embodiments, the outer side of the filter 103 and the inner wall of the cylinder 101 define a sludge channel, and a sludge outlet 303 connected to the sludge channel is provided at the bottom of the side of the cylinder 101. Large particle impurities including microplastics generated in the pretreatment stage of the electrochemical adsorption oxidation unit are discharged through the sludge outlet 303.

[0029] In some embodiments, the supporting layer includes a first supporting layer 1061 located at the bottom, and a plurality of second supporting layers 1062 spaced apart from the first supporting layer 1061 and located above the first supporting layer 1061 and spaced apart from each other; the first supporting layer 1061 is provided with openings having an aperture smaller than the diameter of the three-dimensional particle electrode 105, and the second supporting layer 1062 is provided with openings having an aperture larger than the diameter of the three-dimensional particle electrode 105. The supporting layer adopts a multi-layer structure, which is more conducive to the uniform distribution of the three-dimensional particle electrode 105 than the single-layer structure. At the same time, when the three-dimensional particle electrode 105 has a large adsorption capacity, the second supporting layer 1062 can be used to fix the three-dimensional particle electrode 105 to prevent the three-dimensional particle electrode 105 from dispersing. Furthermore, when the microplastics and other impurities on the three-dimensional particle electrode 105 increase and block the flow of the water body, and generate disturbances so that the three-dimensional particle electrode 105 is disturbed and floated, it can also be used as a time to judge the desorption of the three-dimensional particle electrode 105. Furthermore, the distance between the second supporting layer 1062 and the first supporting layer 1061 , and the distance between each second supporting layer 1062 are greater than the diameter of the three-dimensional granular electrode 105 , and less than twice the diameter of the three-dimensional granular electrode 105 .

[0030] In some of the embodiments, the distance between the cathode 102 and the anode 104 is 10-20 cm; the material of the cathode 102 is ruthenium, iridium, or aluminum; the anode 104 is a titanium filter electrode with a pore size of 0.1-1 mm; the three-dimensional particle electrode 105 is a particle three-dimensional electrode made by oxidation of carbon black coupled iron. Further, the pore size of the titanium filter is 0.03-0.08 mm. The current density during electrolysis can be 1-10 mA / cm2. It is understandable that the distance between the cathode 102 and the anode 104 can also be 12 cm, 14 cm, 16 cm, 18 cm and any point value within the range, and the aperture of the anode 104 can also be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm and any point value within the range.

[0031] In some embodiments, the anode 104 is a titanium filter electrode oxidized at 350°C in a muffle furnace; the three-dimensional particle electrode 105 is a particle electrode oxidized at 200°C by coupling carbon black, phenolic resin and iron powder, wherein the carbon black accounts for 90-98%, the phenolic resin accounts for 1-5%, and the iron powder accounts for 1-5%, and the particle size of the three-dimensional particle electrode 105 is 1-5mm. The particle size of the three-dimensional particle electrode 105 can also be 2 mm, 3 mm, 4 mm and any point value within the range thereof. Among them, the phenolic resin used in the three-dimensional particle electrode 105 plays a bonding role as a combination of carbon black and iron powder before oxidation, and the phenolic resin is consumed after oxidation to increase the specific surface area of ​​the three-dimensional particles, thereby improving the removal effect of microplastics. The carbon black in the particles of the three-dimensional particle electrode 105 has strong adsorption, which can further improve the adsorption performance. The three-dimensional particle electrode 105 is subjected to the action of the induced electric field, wherein the iron in the particles undergoes advanced oxidation to produce hydrogen peroxide and hydroxyl radicals to in-situ oxidize the microplastics, thereby further achieving degradation. The three-dimensional particle electrodes 105 are supported by a bottom supporting layer, and the supporting layer arranges the three-dimensional particle electrodes 105 uniformly.

[0032] In some embodiments, the self-cleaning desorption unit further includes an outlet cover 203 corresponding to the bottom opening of the desorption shell 201, and the outlet cover 203 is conical. The provision of the outlet cover 203 is, on the one hand, conducive to the outlet of the three-dimensional particle electrode 105 concentrated near the inner wall of the desorption shell 201 due to the large gravity during centrifugation, and on the other hand, this structural form is also conducive to the flushing water driving the three-dimensional particle electrode 105 to be desorbed from the top opening of the desorption shell 201 into the desorption shell 201 for centrifugal desorption, ensuring the separation of various material channels and avoiding the effect of mixing.

[0033] In some embodiments, the self-cleaning desorption unit is connected to the anode 104; the desorption shell 201 is made of stainless steel, and a cyclone gallery is provided inside, the inner diameter of the gallery is 5-15 mm, which plays a centrifugal separation role, and is integrally cast on the top of the anode 104; the inner diameter of the outlet pipe 202 is 0.5-4.5 mm. It is understandable that the inner diameter of the gallery can also be 7 mm, 9 mm, 11 mm, 13 mm and any point value within the range, and the inner diameter of the outlet pipe 202 can also be 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm and any point value within the range.

[0034] Another aspect of the present invention discloses a method for removing microplastics from water by using a water purification device for removing microplastics according to any of the above technical solutions, comprising the following steps: The water to be treated flows into the cathode 102 from the sewage inlet 301, and the cathode 102 produces alkali under the action of electrolysis of water. The calcium and magnesium ions contained in the raw water are combined with the alkali precipitated by the cathode 102. After pretreatment by the cathode 102, the large suspended particles are separated by the filter 103. The water filtered by the filter 103 is passed into the three-dimensional particle electrode 105. The microplastic particles in the water are adsorbed on the three-dimensional particle electrode 105 through the positive and negative charges induced by the three-dimensional particle electrode 105, and advanced oxidation occurs on the surface of the three-dimensional particle electrode 105 to achieve the degradation of the microplastics. After being treated by the three-dimensional particle electrode 105, the microplastics are gathered near the anode 104, and are further filtered and oxidized by the anode 104, and the treated water flows out of the filter element of the anode 104 and flows out through the water outlet; When the microplastics and other impurities on the three-dimensional particle electrode 105 increase and block the flow of water, a turbulent flow is generated to disturb the three-dimensional particle electrode 105 and float it. The electrochemical adsorption oxidation unit is turned off and the self-cleaning desorption unit is turned on. The three-dimensional particle electrode 105 is washed to the top by the flushing water and enters the desorption shell 201. The three-dimensional particle electrode 105 is subjected to centrifugal flow in the desorption shell 201. The microplastics and impurities on the three-dimensional particle electrode 105 are thrown out by the centrifugal force and discharged from the outlet pipe 202 with the water flow. The three-dimensional particle electrode 105 returns to the supporting layer from the bottom opening of the desorption shell 201 to complete self-cleaning.

[0035] The advantages of adsorption-coupled electrochemical processes include environmental compatibility, low capital cost, energy efficiency, sludge minimization, ease of automation and cost-effectiveness. The coupled physical removal method is simple and inexpensive. In the water treatment process, the use of chemical reagents is avoided, and the rapid online separation of pollutants is achieved at a lower cost and lower energy consumption. The backwash system uses cyclonic action to achieve efficient system regeneration without the addition of chemicals. The above process uses physical isolation, electrochemical adsorption coupled advanced oxidation system to achieve the removal of microplastics in water without the addition of additional chemicals, and can achieve stable long-term operation through its own efficient backwash device.

[0036] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0037] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A water purification device for removing microplastics, characterized in that: For the removal of microplastics in water, including electrochemical adsorption and oxidation units, and self-cleaning desorption units; The electrochemical adsorption oxidation unit comprises: A cylinder, wherein a sewage inlet is provided at the bottom of the side of the cylinder for sewage containing microplastics to enter the electrochemical adsorption oxidation unit; A cathode, which is sleeved in the cylinder and is a cylindrical stainless steel mesh electrode, with its bottom spaced from the inner wall of the bottom of the cylinder; A filter screen, wherein the filter screen is sleeved in the cathode, and the bottom of the filter screen is connected to the inner wall of the bottom of the cylinder; an anode, the anode being located in the middle of the cylinder; A three-dimensional particle electrode, wherein the three-dimensional particle electrode is disposed between the filter screen and the anode; A supporting layer, used for supporting the three-dimensional particle electrode, wherein the bottom of the supporting layer is provided with an opening whose aperture is smaller than the diameter of the three-dimensional particle electrode; The self-cleaning desorption unit is arranged at the top of the cylinder, and comprises: A desorption shell, which is in an inverted cone shape and rotates under the drive of a driving member, with an opening at the top to allow the three-dimensional particle electrode to enter the shell for centrifugation, and an opening at the bottom to allow the three-dimensional particle electrode to return to the electrochemical adsorption oxidation unit after desorption; A water outlet pipe is arranged in the shell and coincides with the central axis of the shell, and has an opening at the bottom to discharge the desorbed microplastics.

2. The water purification device for removing microplastics according to claim 1, characterized in that: The top of the cylinder is open to allow water for removing microplastics to flow out of the cylinder; the bottom of the cylinder is provided with a flushing water inlet for flushing the three-dimensional particle electrode adsorbed with microplastics from the electrochemical adsorption oxidation unit into the desorption shell; the bottom of the anode is flush with the bottom of the cathode, and the bottom of the supporting layer is flush with the bottom of the cathode.

3. The water purification device for removing microplastics according to claim 2, characterized in that: The outer side surface of the filter screen and the inner wall of the cylinder define a sludge channel, and the bottom of the side surface of the cylinder is provided with a sludge discharge port connected with the sludge channel.

4. The water purification device for removing microplastics according to claim 1, characterized in that: The supporting layer includes a first supporting layer located at the bottom, and a plurality of second supporting layers spaced apart from the first supporting layer and located above the first supporting layer and spaced apart from each other; the first supporting layer is provided with openings having an aperture smaller than the diameter of the three-dimensional granular electrode, and the second supporting layer is provided with openings having an aperture larger than the diameter of the three-dimensional granular electrode.

5. The water purification device for removing microplastics according to claim 4, characterized in that: The distance between the second supporting layer and the first supporting layer, and the distance between the second supporting layers are greater than the diameter of the three-dimensional particle electrode and less than twice the diameter of the three-dimensional particle electrode.

6. The water purification device for removing microplastics according to claim 1, characterized in that: The distance between the cathode and the anode is 10-20 cm; the cathode is made of ruthenium, iridium, or aluminum; the anode is a titanium filter electrode with a pore size of 0.1-1 mm; the three-dimensional particle electrode is a particle three-dimensional electrode made by oxidizing carbon black coupled iron.

7. The water purification device for removing microplastics according to claim 6, characterized in that: The anode is a titanium filter element electrode oxidized at 350°C in a muffle furnace; the three-dimensional particle electrode is a particle electrode oxidized at 200°C by coupling carbon black, phenolic resin and iron powder, wherein the carbon black accounts for 90-98%, the phenolic resin accounts for 1-5%, the iron powder accounts for 1-5%, and the particle size of the three-dimensional particle electrode is 1-5 mm.

8. The water purification device for removing microplastics according to claim 1, characterized in that: The self-cleaning desorption unit further comprises a desorption cover which is arranged corresponding to the bottom opening of the desorption shell, and the desorption cover is conical.

9. The water purification device for removing microplastics according to claim 8, characterized in that: The self-cleaning desorption unit is connected to the anode; the desorption shell is made of stainless steel, and is provided with a cyclone gallery inside, and the inner diameter of the gallery is 5-15 mm; the inner diameter of the water outlet pipe is 0.5-4.5 mm.

10. A method for removing microplastics in water using the water purification device for removing microplastics according to any one of claims 1 to 9, characterized in that: The following steps are involved: The water to be treated flows into the cathode from the sewage inlet, and the cathode produces alkali through the action of electrolyzed water. The calcium and magnesium ions contained in the raw water combine with the alkali produced by the cathode to precipitate. After cathode pretreatment, the large suspended particles are separated by the filter. The water filtered by the filter is passed into the three-dimensional particle electrode. The microplastic particles in the water are adsorbed on the three-dimensional particle electrode through the positive and negative charges induced by the three-dimensional particle electrode, and advanced oxidation occurs on the surface of the three-dimensional particle electrode to achieve the degradation of microplastics. After being treated by the three-dimensional particle electrode, they gather near the anode, and are further filtered and oxidized by the anode, and the treated water flows out of the anode filter element through the water outlet; When the microplastics and other impurities on the three-dimensional particle electrode increase and block the flow of water, a disturbance is generated to disturb the three-dimensional particle electrode and float it. The electrochemical adsorption oxidation unit is closed and the self-cleaning desorption unit is turned on. The three-dimensional particle electrode is flushed to the top under the action of flushing water and enters the desorption shell. The three-dimensional particle electrode is subjected to centrifugal flow in the desorption shell. The microplastics and impurities on the three-dimensional particle electrode are thrown out by centrifugal action and discharged from the outlet pipe with the water flow. The three-dimensional particle electrode returns to the supporting layer from the bottom opening of the desorption shell to complete self-cleaning.

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