Apparatus and method for in-situ enrichment-removal-degradation of microplastics in water body

Abstract

The application provides a device and method for in-situ enrichment-removal-degradation of microplastics in water bodies, which comprises in-situ enrichment of microplastics in water bodies and in-situ degradation of microplastics by water-electricity plasma. First, microplastic adsorption materials are loaded on the blades of a water turbine, and the blades are rotated by water flow to enrich microplastics in the water body to the blade area. Then, the water turbine drives a generator to generate hydroelectricity, and the generated electricity is used to drive a discharge generating device to form plasma high active oxygen substances. Then, carrier gas is adjusted and the enriched microplastic particles are added thereto, and the latter is in-situ harmless degraded by plasma high temperature and active particles to produce carbon dioxide and water. The method provided by the application can quickly enrich microplastics in the water body and effectively remove and degrade the microplastics in-situ, and the method is simple, low in energy consumption, green, environmentally friendly and pollution-free.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of environmental governance, and particularly relates to a device and method for in-situ enrichment-removal-degradation of microplastics in water. BACKGROUND

[0002] Plastics are important basic materials invented by human beings, which have brought great convenience to people's production and life. However, the pollution caused by the large-scale production and use of plastic products to the environment is also increasingly serious. Among them, microplastics with a particle size of less than 5 millimeters as a new emerging pollutant derived from plastics has attracted widespread attention from the international community. According to statistics, about 4.8-12.7 million tons of plastic waste is discharged into the marine ecosystem every year, and the total amount of microplastic particles floating on the ocean surface exceeds 2.44 trillion. Microplastics have characteristics such as small particle size, hydrophobicity, and difficult degradation, and are extremely easy to adsorb organic pollutants and heavy metals in water, thereby causing pollution to animals and plants and the environment. In 2015, the second United Nations Environment Assembly listed microplastics as a new type of environmental pollutant in the second largest scientific issue in the field of environmental and ecological science research, becoming a major global environmental problem together with global climate change and ozone depletion.

[0003] Efficient enrichment and harmless removal of microplastics in water is an important way to solve pollution problems, but microplastics are highly dispersed in water, have a large size span, and vary in shape, making it extremely difficult to enrich. In addition, microplastics are mainly polymers, which have high chemical inertness, posing a great challenge to the efficient degradation of microplastics in a dispersed water environment. Currently, the mainstream method for enriching microplastics in water is physical method, while the removal methods are mainly biological and chemical methods.

[0004] The concentration of microplastics in water is extremely low, the size distribution range is wide, and the main microplastics are extremely fine. Therefore, improving the efficiency of subsequent disposal of microplastics, shortening the disposal period, and reducing energy consumption by rapid adsorption enrichment are the development trends of microplastic removal technology. However, the coupling technology for microplastic adsorption enrichment and efficient removal is not mature, the research on adsorption materials suitable for nanometer-micron wide-scale microplastics is blank, and the related technology is only laboratory research, which has not yet been applied to engineering applications. The Chinese patent document with publication number CN116591127A discloses a multi-application-scenario marine floating garbage recycling device, which selects a double-layer filter screen structure, which can recycle conventional marine floating garbage and also recycle microplastics (0.15mm-5mm) of larger size. However, this method is limited by the size of the filter screen and cannot collect smaller micro-nano plastics, and the adsorption efficiency is not high. Therefore, there is an urgent need to develop high-efficiency enrichment-related technology suitable for deep disposal of low-abundance micro-nano plastics in water.

[0005] Microplastics in water bodies are an emerging environmental problem, and research and application of removal methods are still in their early stages, with no mature and reliable dedicated technologies yet. Currently, the main methods of interest include biological and chemical methods. Biological methods primarily utilize the metabolic activity of organisms such as fungi, bacteria, or algae to degrade polymeric microplastics. They offer advantages such as low operating costs and mature technology, but are only effective for specific microplastics like PP and PET, and their degradation efficiency is relatively low. Furthermore, they have long treatment cycles (up to tens of days) and require large land areas, making them unsuitable for rapid, decentralized microplastic disposal in water bodies. Current research on chemical methods mainly focuses on advanced oxidation processes, which utilize the strong oxidizing properties of free radicals or other active components to achieve the oxidative degradation of microplastics. For example, persulfate can generate sulfate and hydroxyl radicals with high oxidation potential and strong oxidizing power. However, this method is still immature, and the degradation efficiency needs improvement (e.g., only 54% degradation rate after 8 hours). It also easily causes secondary pollution to water bodies, thus limiting its application scenarios. Thermal treatment methods can also efficiently convert microplastics and are a conventional technology for the disposal of traditional solid waste. However, they are large-scale and require significant land area, and secondary pollution is difficult to control, making them unsuitable for distributed microplastic removal scenarios. Chinese patent document CN117244924A discloses a method for the rapid degradation and removal of full-size microplastics based on photothermal catalysis and photoelectric plasma cascade coupling. This method addresses the shortcomings of existing technologies by providing a rapid degradation and removal method for full-size microplastics based on photothermal catalysis and photoelectric plasma cascade coupling. It utilizes the high-temperature photothermal catalytic reaction of concentrated solar energy to achieve efficient decomposition and oxidation of complex mixed microplastics, and utilizes the high-efficiency oxidation reaction of solar photovoltaic-driven plasma to further oxidize and degrade decomposition products and waste gases. This method is applicable to the degradation and removal of full-size microplastic pollutants, but it is limited by light conditions and energy storage technology, and cannot achieve one-step rapid removal of microplastics. To date, there is still a lack of efficient and stable methods for microplastic pollution control. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing an apparatus and method for in-situ enrichment, removal, and degradation of microplastics in water.

[0007] The objective of this invention is achieved through the following technical solution: an in-situ enrichment-removal and degradation device for microplastics in water, comprising: a water turbine, a generator, and a plasma discharge device;

[0008] The turbine blades are loaded with graded pore adsorption material to achieve in-situ enrichment of mixed microplastics in the water under the impetus of water flow.

[0009] The generator set is connected to the water turbine, converting the mechanical energy of the water turbine into electrical energy. The generator set is connected to the main unit of the plasma generator through a transformer for power supply.

[0010] The plasma discharge device ionizes the air flowing through the device to form a jet, generating high active oxygen substances; the enriched micro-nano plastic particles are mixed into the plasma carrier gas and react with the high active oxygen substances, and the micro-plastics are harmless degraded into CO2 and H2O through high temperature and oxidation.

[0011] Further, the hierarchical pore adsorbent material is modified activated carbon, and the void structure is adjusted according to the preparation process and includes micropores, mesopores, and macropores.

[0012] Further, the hierarchical pore adsorbent material is loaded on the water turbine blade using a chemical bonding method.

[0013] Further, the water turbine and generator set is a variable-pitch water turbine.

[0014] Further, the water turbine blade is a detachable structure for desorbing micro-plastic particles in a low-pressure environment, and then the water turbine blade is reused.

[0015] Further, the transformer converts the alternating current output by the hydroelectric generator set into 220V / 50Hz alternating current to power the plasma generating device.

[0016] Further, the high-voltage direct-current signal output by the main machine of the plasma generating device has a continuously adjustable output voltage of 0-10kV and a continuously adjustable output current of 0-0.6A.

[0017] According to the second aspect of the description, a water body micro-plastic in-situ enrichment-removal degradation method is also provided, which comprises:

[0018] Water body micro-plastic in-situ enrichment: a hierarchical pore adsorbent material is loaded on the water turbine blade, which can realize in-situ enrichment of mixed micro-nano plastics in the water body. The water turbine rotates continuously under the push of the water flow, realizing efficient enrichment of micro-plastics in the water body.

[0019] Micro-plastic desorption mixed air: the adsorbed water turbine blade is taken out, first dried in an 80℃ oven, then placed in a low-pressure or vacuum environment to desorb the adsorbed micro-plastic particles from the surface of the activated carbon, and then collected and placed in the micro-plastic inlet of the plasma device. Finally, by controlling the opening and closing of the electromagnetic valve of the plasma device, the micro-plastic particles are mixed into the air, and then supported by the carrier gas to form a plasma jet along the pipeline.

[0020] Hydroelectric-plasma in-situ degradation reaction: using hydroelectric power to power the plasma generating device, the plasma ionizes the air flowing through the device to form a jet, generating high active oxygen species; the enriched micro-nano plastic particles are mixed into the plasma carrier gas and react with the high active oxygen species, and the micro-plastics are harmlessly degraded into CO2 and H2O through high temperature and oxidation.

[0021] Advantages

[0022] The present application provides a water body microplastic in-situ enrichment technology, by loading adsorption material in the blade, making it fully contact with the water body with the rotation of the water turbine, achieving 100% adsorption enrichment efficiency of micron-sized microplastics, and >99% adsorption enrichment efficiency of nanometer-sized microplastics. This method realizes efficient enrichment of low-abundance micro-nano plastics in water.

[0023] The present application uses plasma jet oxidation technology to remove and degrade the enriched microplastic particles, and the high active oxygen species generated by the plasma jet directly reacts with the enriched microplastic particles to completely degrade them into CO2 and H2O, which are finally discharged into the atmosphere. This method is green and environmentally friendly, and has fast degradation speed.

[0024] In the water body microplastic in-situ enrichment-removal and degradation method proposed by the present application, the energy required for microplastic degradation is entirely derived from hydroelectric power, which drives the water turbine to rotate, realizes efficient enrichment of microplastics in water by adsorption material, and realizes rapid degradation of microplastics by plasma jet generated by hydroelectric power. This method has low energy consumption and low cost. The use of microplastic adsorption material loaded on the water turbine blade realizes complete adsorption and enrichment of micron-sized microplastics, and efficient adsorption and enrichment of nanometer-sized microplastics; the use of plasma jet generated by hydroelectric power realizes efficient oxidation and complete removal and degradation of microplastics.

[0025] The present application is used for efficient enrichment and complete removal of micro-nano plastics in water, has the characteristics of simple operation, high efficiency, low energy consumption, green environmental protection, etc., and solves the problem of deep disposal of low-abundance micro-nano plastics in water in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The flow chart of the water body microplastic in-situ enrichment-removal and degradation method proposed by the present application is shown in the figure;

[0027] Figure 2 The schematic diagram of the water turbine blade is shown in the figure;

[0028] Figure 3 The schematic diagram of the plasma jet structure is shown in the figure. DETAILED DESCRIPTION

[0029] The specific embodiments of the present application are further described in detail below with reference to the accompanying drawings.

[0030] The embodiment provides a water body microplastic in-situ enrichment-removal degradation device and method. Figure 1 The device comprises a water turbine, a generator and a plasma discharge device.

[0031] The blades in the water turbine are loaded with hierarchical pore adsorbent materials, which are used to realize in-situ enrichment of mixed microplastics in the water body under the driving of water flow; and the water turbine is a rotating propeller type water turbine. The hierarchical pore adsorbent materials are used to treat microplastics in the water body. For different water bodies, the preparation process of activated carbon is adjusted, the appropriate pore structure is selected, the large, medium and small pores and hollow structure of the adsorbent are utilized, the diffusion distance of large particle microplastics is shortened, the diffusion capacity of small particle microplastics is enhanced, and the optimized adsorption active sites are combined to realize targeted and efficient removal of microplastics of different sizes. The adsorbent interface is regulated to realize the hydrophilic and hydrophobic adsorption of complex component microplastics. The pore structure includes micropores (less than 2 nanometers), mesopores (2 to 50 nanometers) and macropores (greater than 50 nanometers), and the actual pore structure needs to be determined according to the diameter distribution of microplastics in different water bodies.

[0032] The generator set is connected with the water turbine to convert mechanical energy of the water turbine into electric energy. The generator set is connected with the host of the plasma generating device through a transformer for power supply. The output voltage of the host of the plasma generating device is about 1.5 kV, the output current is 0.2 A, and the overall power consumption is 250-300 W.

[0033] The power generation capacity of the water turbine and the generator set is 300-500 W.

[0034] The plasma discharge device ionizes air flowing through the device to form a jet flow and generate high active oxygen substances. The enriched micro-nano plastic particles are mixed into the plasma carrier gas and react with the high active oxygen substances. Through high temperature and oxidation, the microplastics are harmlessly degraded into CO2 and H2O.

[0035] According to the above device embodiment, a water body microplastic in-situ enrichment-removal degradation method using the device is also provided.

[0036] (1) Water body microplastic in-situ enrichment process: a hierarchical pore adsorbent material is loaded on the blades of the water turbine by using a chemical bonding method. The state of the blades after loading is shown in Figure 2 The hierarchical pore adsorbent material is modified activated carbon. The flowing water body is introduced into the water turbine, and the water turbine is continuously rotated by the water flow. The adsorbent material on the blades enriches microplastics in the water body during rotation, completely adsorbs micron-sized microplastics, and efficiently adsorbs nanometer-sized microplastics.

[0037] The present application utilizes hierarchical pore adsorbent materials to treat microplastics in water bodies. For different water body conditions, by adjusting the activated carbon preparation process, selecting the appropriate pore structure, utilizing the large, medium and small pores and hollow structure of the adsorbent, shortening the diffusion distance of large particle microplastics, enhancing the diffusion capacity of small particle microplastics, and combining with the optimized adsorption active site, the targeted and efficient removal of microplastics of different sizes is realized. The adsorbent interface regulation realizes the hydrophilic and hydrophobic adsorption of complex component microplastics. The void structure includes micropores (less than 2 nanometers), mesopores (2 to 50 nanometers) and macropores (greater than 50 nanometers), and the actual pore structure needs to be determined according to the diameter distribution of microplastics in different water bodies.

[0038] (2) Microplastic desorption mixed air process: the adsorbed water turbine blade is taken out, first placed in an 80℃ oven to dry the moisture, then the blade is placed in a low pressure or vacuum environment to desorb the adsorbed microplastic particles from the surface of the activated carbon, then the desorbed microplastic particles are collected and placed in the microplastic inlet of the plasma device, finally the electromagnetic valve of the plasma device is controlled to open and close, so that the microplastic particles are mixed into the air, and then supported by the carrier gas to form a plasma jet. See Figure 3 And the desorbed water turbine blade is restored to activity and can be reused subsequently.

[0039] (3) Water-electricity-plasma in-situ degradation reaction: see Figure 3 The device components are installed and connected as shown in the figure, the plasma generating device is connected to the lower reaction chamber through a flange, and the entire system is connected to the gas inlet and exhaust along the arrow direction.

[0040] The stainless steel rod in the middle and the peripheral stainless steel ring block serve as the positive and negative electrodes of the plasma discharge device, respectively.

[0041] When the system is working, the carrier gas needs to be introduced first, and then the high-voltage power supply is turned on. The carrier gas flows through the middle of the high-voltage electrode to form a jet. The energy required by the plasma generating device is provided by the hydroelectric generator set. The output end of the hydroelectric generator set is connected to a transformer, which adjusts the output alternating current to 220V / 50Hz specifications, and then connected to the main machine of the plasma generating device. A large amount of highly active oxygen substances are produced by the plasma jet, which contacts with the microplastic particles in the carrier gas, and through high temperature and oxidation, the latter is completely degraded into CO2 and H2O.

[0042] The present application utilizes the high temperature and oxidation effect produced by the plasma jet technology to degrade microplastic particles. Compared with photocatalysis and biological treatment, the present application has more remarkable desorption efficiency and disposal period, and is more universal in terms of microplastic types and sizes. The device structure is simple, and the microplastic particles can be directly converted into harmless carbon dioxide and water in one step.

[0043] The required energy in the application is from the hydroelectric power generation, which greatly reduces the energy consumption in the whole process, and the method can be independently operated without external continuous power supply.

[0044] The above examples are used to explain and illustrate the application, but not to limit the application, and any modification and change made to the application within the spirit and protection scope of the claims falls into the protection scope of the application.

Claims

1. A device for in-situ enrichment-removal-degradation of microplastics in water bodies, characterized in that, Comprise: A water turbine, a generator, a plasma discharge device; A graded-pore adsorbent material loaded on the blades of the water turbine for in-situ enrichment of mixed microplastics in water bodies under the impetus of water flow; The graded-pore adsorbent material is modified activated carbon, and the pore structure is adjusted according to the preparation process, including micropores, mesopores and macropores; The water turbine blades are detachable structures for desorption of microplastic particles in a low-pressure environment, and then the water turbine blades are put into use again; The generator is connected with the water turbine to convert the mechanical energy of the water turbine into electrical energy, and the generator is connected with the main machine of the plasma discharge device through a transformer for power supply; The plasma discharge device ionizes the air flowing through the device to form a jet, generating highly active oxygen substances; the enriched microplastic particles are mixed into the plasma carrier gas and react with the highly active oxygen substances, and the microplastics are harmlessly degraded into CO2 and H2O through high temperature and oxidation. 2.The water microplastic in-situ enrichment-removal-degradation device according to claim 1, characterized in that, The modified activated carbon is loaded on the water turbine blades by chemical bonding method. 3.The water microplastic in-situ enrichment-removal-degradation device according to claim 1, characterized in that, The water turbine is a propeller-type water turbine.

4. The water body microplastic in-situ enrichment-removal-degradation device according to claim 1, characterized in that, The transformer converts the alternating current output by the generator into 220V / 50Hz alternating current to power the plasma discharge device.

5. The water body microplastic in-situ enrichment-removal-degradation device according to claim 1, characterized in that, The main machine of the plasma discharge device outputs a high-voltage direct-current signal with a continuously adjustable output voltage of 0-10kV and a continuously adjustable output current of 0-0.6A.

6. A method for in-situ enrichment-removal-degradation of microplastics in water bodies using the device of any one of claims 1-5, characterized in that, The method comprises: In-situ enrichment of microplastics in water bodies: modified activated carbon is loaded on the water turbine blades to achieve in-situ enrichment of microplastics in water bodies, and the water turbine continuously rotates under the impetus of water flow to achieve efficient enrichment of microplastics in water bodies; Desorption and mixing of microplastics with air: the water turbine blades after adsorption are taken out, first dried in an 80℃ oven, and then placed in a low-pressure or vacuum environment to desorb the adsorbed microplastic particles from the surface of the modified activated carbon, and then the desorbed microplastic particles are collected and placed in the microplastic inlet of the plasma discharge device, and finally the electromagnetic valve of the plasma discharge device is controlled to open and close, so that the microplastic particles are mixed into the air, and then follow the pipeline as the carrier gas to support the formation of plasma jet; Hydroelectric-plasma in-situ degradation reaction: hydropower is used to power the plasma discharge device, the plasma ionizes the air flowing through the device to form a jet, generating highly active oxygen substances; the enriched microplastic particles are mixed into the plasma carrier gas and react with the highly active oxygen substances, and the microplastics are harmlessly degraded into CO2 and H2O through high temperature and oxidation.

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