Liquid film reaction device and method based on dielectric barrier microplasma discharge

Abstract

The present invention discloses a liquid film reaction device and method based on dielectric barrier microplasma discharge. The device includes a power supply, a dielectric barrier microdischarge device, and a liquid input system. The dielectric barrier microdischarge device includes an insulating medium, a high-voltage electrode, and a ground electrode, with the power supply connected to the high-voltage electrode and the ground electrode, respectively. The liquid input system includes a liquid container and a water pipe, with the liquid container connected to the water inlet of the dielectric barrier microdischarge device via the water pipe. The device can perform liquid film dielectric barrier microplasma discharge at room temperature and pressure using common gases, air, and water as raw materials, achieving nitrogen / carbon fixation and organic wastewater degradation under mild conditions. The device has a simple structure, is compact and portable, uses cheap gas, has low technical costs, and has the characteristics of fast reaction speed and high energy efficiency. It can degrade organic wastewater and utilize the products of the nitrogen / carbon fixation process for drip irrigation of crops, providing carbon, nitrogen, and other elements to promote crop growth.

Description

Technical Field

[0001] The present invention relates to the field of plasma technology, and in particular to a device and method for liquid film reaction based on dielectric barrier microplasma discharge. Background Art

[0002] Nitrogen is an essential component of living organisms. It is an important component of amino acids, proteins, nucleic acids, etc. The nitrogen fixation process is closely related to human survival. Because the N≡N bond in nitrogen molecules is very stable, nitrogen in the air cannot be directly converted and utilized by most organisms. Biological nitrogen fixation cannot meet the growing needs of society, which has promoted the research and development of artificial nitrogen fixation. In recent years, the development of sustainable, green and low-carbon nitrogen fixation technologies has gradually become a research hotspot, mainly including electrocatalysis, photocatalysis, biotechnology and plasma technology. These technologies are used to reduce nitrogen to produce NH3 and oxidize nitrogen to produce NO3 - / NO2 - Nitrogen fixation can be achieved through reactions such as the production of amino fertilizers. Among them, non-thermal plasma technology has attracted much attention due to its low temperature, mildness and high reaction activity, and has been widely used in the research of nitrogen fixation technology.

[0003] N2 fixation is a crucial process. The products produced by non-thermal plasma fixation of N2 are generally of two types, namely NH3 and NO. x , which are the main components of fertilizers and are also essential for agriculture. This is because plasma contains a large number of high-energy electrons, highly active particles, excited species, and free radicals, which can enable reactions such as N2 dissociation, which is not easy to occur under normal conditions, to proceed at room temperature and pressure. In addition, plasma technology also has broad application prospects in the treatment of organic wastewater. The high-energy electrons and key active species such as H2O2, ·OH, and O3 in the plasma can act on the organic molecules in the organic wastewater, causing a series of physical and chemical reactions to destroy the chemical molecular structure of the organic matter, thereby achieving efficient degradation and treatment of organic wastewater.

[0004] There are many non-thermal plasma discharge systems, including dielectric barrier discharge (DBD), radio frequency discharge, glow discharge, and microwave discharge. Compared with other discharge forms, DBD exhibits advantages such as better discharge uniformity for the conversion of CO2, CH4, and N2 at room temperature and atmospheric pressure.

[0005] Therefore, a liquid membrane reaction device and method based on plasma-assisted conversion of CO2 and N2 into plant nutrients is needed to achieve nitrogen fixation / carbon fixation (mainly participated by gas sources containing CO2 and CH4 gases) plasma chemical reaction, generate liquid-phase carbon-nitrogen organic matter and degrade organic wastewater. Summary of the Invention

[0006] To address these issues, the present invention provides a liquid film reaction device and method based on dielectric-barrier microplasma discharge. This device utilizes common gases (N2, CO2, CH4, or O2), air, and water as feedstocks to perform liquid film-dielectric-barrier microplasma discharge at room temperature and pressure, achieving nitrogen and carbon fixation and organic wastewater degradation under mild conditions. The device is simple and portable, utilizes inexpensive gas, and offers low technical costs. It features fast reaction speed and high energy efficiency. The products of the nitrogen and carbon fixation process can be used for drip irrigation of crops, providing carbon, nitrogen, and other elements to promote crop growth.

[0007] A first object of the present invention is to provide a liquid film reaction device based on dielectric barrier microplasma discharge, comprising a power supply, a dielectric barrier microdischarge device and a liquid input system; the dielectric barrier microdischarge device comprises an insulating medium, a high-voltage electrode and a grounding electrode, and the power supply is connected to the high-voltage electrode and the grounding electrode respectively; the liquid input system comprises a liquid container and a water pipe, and the liquid container is connected to the water inlet end of the dielectric barrier microdischarge device via the water pipe; the dielectric barrier microdischarge device comprises a three-way dielectric barrier microdischarge device, a planar single dielectric barrier microdischarge device or a planar double dielectric barrier microdischarge device; the insulating medium of the three-way dielectric barrier microdischarge device is a three-way tubular structure, and the high-voltage electrode is arranged inside the insulating medium; the high-voltage electrode and the insulating medium of the planar single dielectric barrier microdischarge device and the planar double dielectric barrier microdischarge device are sheet-like structures.

[0008] In one embodiment of the present invention, the insulating medium of the three-way dielectric barrier micro-discharge device includes an upper tube section and a lower tube section that are interconnected, and the high-voltage electrode of the three-way dielectric barrier micro-discharge device includes a metal hollow cylinder and a hollow end head that are interconnected; the lower tube section of the insulating medium is a liquid flow channel, one side of which is a water inlet end and the other side is a water outlet end; the hollow end head of the high-voltage electrode is mounted on the upper tube section of the insulating medium, and the hollow end head is the air inlet end of the dielectric barrier micro-discharge device; the hollow cylinder of the high-voltage electrode is located inside the upper tube section of the insulating medium and extends into the lower tube section of the insulating medium; the bottom of the hollow cylinder of the high-voltage electrode is the discharge end, which is provided with an opening perpendicular to the direction of liquid flow; the grounding electrode is attached to the outer wall of the lower tube section of the insulating medium away from the end of the upper tube section.

[0009] In one embodiment of the present invention, a gas supply system is further included, which includes an air pump, a gas bottle and a gas pipe. The air pump, gas bottle and gas pipe are connected by a three-way pipe. The other end of the gas pipe is connected to the air inlet end of the dielectric barrier micro-discharge device, and the gas pipe is provided with a gas flow meter.

[0010] In one embodiment of the present invention, the diameter of the hollow cylinder of the high-voltage electrode ranges from 3.0 to 5.0 mm, and the diameter of the opening at the bottom discharge end of the hollow cylinder of the high-voltage electrode ranges from 0.5 to 1.5 mm.

[0011] In one embodiment of the present invention, the high-voltage electrode of the planar single dielectric barrier micro-discharge device is arranged opposite to the insulating medium, and isolation layer gaskets are provided on both sides between the high-voltage electrode and the insulating medium. A flow channel for liquid flow is formed between the two isolation layer gaskets, one end of the flow channel is the water inlet end of the dielectric barrier micro-discharge device, and the other end is the water outlet end of the dielectric barrier micro-discharge device; the ground electrode is provided on the outer wall at the bottom center of the insulating medium; the flow channel is in the form of a groove, a groove, or a frosted surface.

[0012] In one embodiment of the present invention, the width of the flow channel ranges from 1.0 to 15.0 mm; the thickness of the insulating medium ranges from 1.0 to 2.0 mm; and the isolation layer gasket is made of glass, quartz, ceramic or alumina.

[0013] In one embodiment of the present invention, the two insulating media of the planar dual-dielectric barrier micro-discharge device are arranged relative to each other, a high-voltage electrode is provided above one of the insulating media, and a ground electrode is provided below the other insulating medium. Isolation layer gaskets are provided on both sides between the two insulating media, and a flow channel for liquid flow is formed between the two isolation layer gaskets. One end of the flow channel is the water inlet end of the dielectric barrier micro-discharge device, and the other end is the water outlet end of the dielectric barrier micro-discharge device; the ground electrode is provided on the outer wall at the bottom center of one of the insulating media, and the high-voltage electrode is provided on the outer wall at the top center of the other insulating medium; the flow channel is in the form of a groove, a groove, or a frosted surface.

[0014] In one embodiment of the present invention, the power supply is a high-voltage power supply, and its output voltage range is 1.0 to 5.0 kV; the grounding electrode is mesh-shaped, linear or sheet-shaped, closely attached to the outer wall of the insulating medium, and connected to the grounding terminal of the high-voltage power supply; the discharge distance between the grounding electrode and the high-voltage electrode ranges from 1.0 to 10.0 mm; the material of the insulating medium is glass, quartz, ceramic or alumina, and the materials of the high-voltage electrode and the grounding electrode are copper, tin, aluminum, tungsten, titanium, stainless steel or metal alloy.

[0015] A second object of the present invention is to provide a method for fixing nitrogen, fixing carbon, or degrading organic wastewater using a liquid film reaction device based on dielectric barrier micro-plasma discharge. The method uses the liquid film reaction device based on dielectric barrier micro-plasma discharge, and comprises the following steps:

[0016] Step 1: Turn on the power supply and deliver the discharge gas to the hollow cylinder of the high-voltage electrode in the three-way dielectric barrier micro-discharge device, or to the input end of the flow channel of the planar single dielectric barrier micro-discharge device / planar double dielectric barrier micro-discharge device through an air pump or gas bottle. The discharge gas generates dielectric barrier discharge between the ground electrode and the high-voltage electrode.

[0017] Step 2: The reaction liquid flows into the water delivery end through the water delivery pipe to form a uniform water film and pass through the flow channel;

[0018] Step 3: During the reaction, samples are taken regularly and the reaction liquid is replenished in time.

[0019] In one embodiment of the present invention, the reaction liquid comprises deionized water, pure water, and an organic pollutant solution; the reaction liquid flow rate in step 2 is 5.0 to 20.0 mL / min; the discharge gas in step 1 is argon, oxygen, nitrogen, air, or a mixture thereof, with a flow rate of 1.0 to 8.0 L / min; the discharge voltage is controlled to vary between 1.0 and 5.0 kV, and the pulse frequency is adjusted between 10.0 and 16.0 kHz.

[0020] The present invention has the following beneficial effects:

[0021] (1) The device provided by the present invention uses common gas sources, air and water as basic raw materials. The gas source is easy to obtain. In addition, the device uses dielectric barrier discharge, which can effectively reduce the contact corrosion between the liquid and the electrode and reduce the loss of the device.

[0022] (2) The device provided by the present invention is a dielectric barrier microplasma discharge. Compared with traditional plasma, the electrode gap of microplasma discharge is smaller (the scale is on the order of millimeters or even lower), which can more easily generate active species and has the characteristics of low power consumption, high active species density and high stability.

[0023] (3) The device provided by the present invention is a reaction device that uses a liquid film medium to block microplasma discharge. The surface of the insulating medium at the grounded electrode end of the reaction device is covered with a layer of flowing liquid film. Since the liquid film has a large surface area, the active particles in the gas phase of the discharge area can quickly diffuse into the solution and maintain a high chemical activity. The fluidity of the liquid film makes the contact between the plasma and the solution more complete, which is more conducive to the mass transfer of active particle substances from the gas phase to the liquid phase.

[0024] In summary, the present invention has a simple structure, small size, low technical cost, can realize miniaturized operation, can realize nitrogen fixation, carbon fixation and organic wastewater degradation under mild conditions, has the characteristics of fast reaction speed and high energy efficiency, and at the same time, the treated products can be used for drip irrigation of crops, providing carbon, nitrogen and other elements to promote crop growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a schematic structural diagram of the first liquid film reaction device based on dielectric barrier microplasma discharge provided by the present invention.

[0027] Figure 2 This is a schematic structural diagram of the second liquid film reaction device based on dielectric barrier microplasma discharge provided by the present invention.

[0028] Figure 3 This is a schematic structural diagram of the first dielectric barrier micro-discharge device (three-way dielectric barrier micro-discharge device) provided by the present invention.

[0029] Figure 4 This is a schematic structural diagram of the second dielectric barrier micro-discharge device (planar single dielectric barrier micro-discharge device) provided by the present invention.

[0030] Figure 5 This is a schematic structural diagram of the third dielectric barrier micro-discharge device (planar dual dielectric barrier micro-discharge device) provided by the present invention.

[0031] In the figure: 1-power supply, 2-gas supply system, 3-dielectric barrier micro-discharge device, 4-liquid input system, 5-air pump, 6-gas bottle, 7-gas flow meter, 8-insulating medium, 81-upper pipe section, 82-lower pipe section, 9-high voltage electrode, 91-hollow end, 92-hollow cylinder, 10-ground electrode, 11-flow channel, 12-isolation layer gasket. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] In the present invention, unless otherwise expressly specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0034] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0035] Example 1

[0036] like Figure 1 and 2 As shown, this embodiment provides a liquid film reaction device based on dielectric barrier microplasma discharge, including a power supply 1, a dielectric barrier micro-discharge device 3 and a liquid input system 4; the dielectric barrier micro-discharge device 3 includes an insulating medium 8, a high-voltage electrode 9 and a grounding electrode 10, and the power supply 1 is connected to the high-voltage electrode 9 and the grounding electrode 10 respectively; the liquid input system 4 includes a liquid container and a water pipe, and the liquid container is connected to the water inlet end of the dielectric barrier micro-discharge device 3 through the water pipe.

[0037] Alternatively, as Figure 1 and 3 As shown, Figure 1 This is a schematic structural diagram of the first liquid film reaction device based on dielectric barrier micro plasma discharge provided by the present invention. The dielectric barrier micro discharge device 3 in the device is Figure 3 The three-way dielectric barrier micro-discharge device shown in ; Figure 3This is a schematic diagram of the structure of the first dielectric barrier micro-discharge device (three-way dielectric barrier micro-discharge device) provided by the present invention. The dielectric barrier micro-discharge device 3 is a three-way dielectric barrier micro-discharge device. The insulating medium 8 of the three-way dielectric barrier micro-discharge device is a three-way tubular structure, including an upper tube section 81 and a lower tube section 82 that are interconnected. The high-voltage electrode 9 of the three-way dielectric barrier micro-discharge device includes a metal hollow cylinder 92 and a hollow end 91 that are interconnected. The lower tube section 82 of the insulating medium 8 is a liquid flow channel, with one side of the liquid inlet end and the other side of the liquid outlet end. The hollow end 91 of the high-voltage electrode 9 1 is mounted on the upper tube section 81 of the insulating medium 8, the hollow end 91 serves as the air inlet end of the dielectric barrier micro-discharge device 3, the hollow cylinder 92 of the high-voltage electrode 9 is located inside the upper tube section 81 of the insulating medium 8 and extends into the lower tube section 82 of the insulating medium 8; the bottom of the hollow cylinder 92 of the high-voltage electrode 9 serves as the discharge end, and is provided with an opening perpendicular to the direction of liquid flow; the grounding electrode 10 is attached to the outer wall of the lower tube section 82 of the insulating medium 8 at the end away from the upper tube section 81.

[0038] Furthermore, it also includes a gas supply system 2, which includes an air pump 5, a gas bottle 6 and a gas pipe. The air pump 5, the gas bottle 6 and the gas pipe are connected by a three-way pipe. The other end of the gas pipe is connected to the air inlet end of the dielectric barrier micro-discharge device 3. The gas pipe is provided with a gas flow meter 7.

[0039] Furthermore, the diameter of the hollow cylinder 92 of the high-voltage electrode 9 is in the range of 3.0 to 5.0 mm, and the diameter of the opening at the bottom discharge end of the hollow cylinder 92 of the high-voltage electrode 9 is in the range of 0.5 to 1.5 mm.

[0040] Alternatively, as Figure 2 and 4 As shown, Figure 2 This is a schematic diagram of the structure of the second liquid film reaction device based on dielectric barrier micro plasma discharge provided by the present invention. The dielectric barrier micro discharge device 3 in the device is Figure 4 The planar single dielectric barrier micro-discharge device shown in ; Figure 4 This is a schematic diagram of the structure of the second dielectric barrier micro-discharge device (a planar single dielectric barrier micro-discharge device) provided by the present invention. This dielectric barrier micro-discharge device 3 is a planar single dielectric barrier micro-discharge device. The high-voltage electrode 9 and the insulating medium 8 of this planar single dielectric barrier micro-discharge device are sheet-like structures and arranged opposite each other. Isolation layer gaskets 12 are provided on both sides between the high-voltage electrode 9 and the insulating medium 8. A flow channel 11 for liquid flow is formed between the two isolation layer gaskets 12. One end of the flow channel 11 serves as the water inlet of the dielectric barrier micro-discharge device 3, and the other end serves as the water outlet. A ground electrode 10 is provided on the outer wall at the bottom center of the insulating medium 8.

[0041] Furthermore, the width of the flow channel 11 ranges from 1.0 to 15.0 mm; the thickness of the insulating medium 8 ranges from 1.0 to 2.0 mm.

[0042] Furthermore, the isolation layer gasket 12 is made of glass, quartz, ceramic or aluminum oxide.

[0043] Alternatively, as Figure 5 As shown, Figure 5 The third dielectric barrier micro-discharge device (planar dual dielectric barrier micro-discharge device) provided by the present invention is a schematic structural diagram. The dielectric barrier micro-discharge device 3 is a planar dual dielectric barrier micro-discharge device. Figure 4 Compared to the planar single dielectric barrier micro-discharge device, an insulating medium 8 can be connected to the end of the high-voltage electrode 9 to form a dual dielectric barrier discharge. The high-voltage electrode 9 and the insulating medium 8 of the planar dual dielectric barrier micro-discharge device are sheet-like structures. The two insulating dielectrics 8 are arranged opposite each other, with the high-voltage electrode 9 disposed above one insulating dielectric 8 and a grounding electrode 10 disposed below the other insulating dielectric 8. Isolation layer gaskets 12 are disposed on both sides between the two insulating dielectrics 8. A flow channel 11 for liquid flow is formed between the two insulating layer gaskets 12. One end of the flow channel 11 is the water inlet end of the dielectric barrier micro-discharge device 3, and the other end is the water outlet end of the dielectric barrier micro-discharge device 3. The grounding electrode 10 is disposed on the outer wall at the bottom center of one insulating dielectric 8, and the high-voltage electrode 9 is disposed on the outer wall at the top center of the other insulating dielectric 8.

[0044] Optionally, the flow channel 11 is in a grooved, recessed or frosted form, which is easy to form a flowing liquid film.

[0045] Optionally, the high-voltage electrode 9 may also be a mesh structure.

[0046] Optionally, the power supply 1 is a high-voltage power supply, and its output voltage range is 1.0 to 5.0 kV.

[0047] Optionally, the ground electrode 10 is in mesh, line or sheet shape, is closely attached to the outer wall of the insulating medium, and is connected to the ground terminal of the high voltage power supply.

[0048] Optionally, the discharge distance between the ground electrode 10 and the high-voltage electrode 9 is in the range of 1.0 to 10.0 mm.

[0049] Optionally, the insulating medium 8 is made of glass, quartz, ceramic or aluminum oxide, and the high-voltage electrode 9 and the grounding electrode 10 are made of copper, tin, aluminum, tungsten, titanium, stainless steel or metal alloy.

[0050] Example 2

[0051] This embodiment provides a method for fixing nitrogen, fixing carbon, or degrading organic wastewater using a liquid film reaction device based on dielectric barrier micro-plasma discharge. The method uses the liquid film reaction device based on dielectric barrier micro-plasma discharge provided in Example 1 and includes the following steps:

[0052] Step 1: Turn on the power supply and deliver the discharge gas to the hollow cylinder 92 of the high-voltage electrode in the three-way dielectric barrier micro-discharge device, or to the input end of the flow channel of the planar single dielectric barrier micro-discharge device / planar double dielectric barrier micro-discharge device, through an air pump or gas bottle. The discharge gas generates dielectric barrier discharge between the ground electrode and the high-voltage electrode.

[0053] Step 2: The reaction liquid flows into the water delivery end through the water delivery pipe at a certain flow rate to form a relatively uniform water film passing through the flow channel;

[0054] Step 3: During the reaction, samples are taken regularly and the reaction liquid is replenished in time.

[0055] In which, the reaction liquid is deionized water, pure water or an organic pollutant solution; the flow rate of the reaction liquid in step 2 is 5.0 to 20.0 mL / min; the discharge gas in step 1 is argon, oxygen, nitrogen, air or a gas mixed with other gases, with a flow rate of 1.0 to 8.0 L / min; the discharge voltage is controlled to vary between 1.0 and 5.0 kV, and the pulse frequency is adjusted between 10.0 and 16.0 kHz.

[0056] Example 3

[0057] The present invention provides a method for treating organic wastewater based on a liquid film dielectric barrier microplasma discharge reaction device. The organic wastewater in a liquid container is transported to the dielectric barrier micro-discharge device through a water pipe to form a relatively uniform flowing water film. High-energy electrons and active species such as H2O2, OH, and O3 generated during the dielectric barrier micro-discharge process react with the organic wastewater to degrade pollutants. The treated water can flow back to the liquid container through a liquid collection device, forming multiple circulation treatments to ensure full contact between the treated water and the organic wastewater, thereby improving the degradation effect of the organic wastewater.

[0058] Organic wastewater degradation principle: The device's liquid-film plasma discharge region excites and ionizes nitrogen, oxygen, and water vapor in the air. Through a series of physicochemical reactions, these molecules produce active species such as H2O2, ·OH, O3, and oxygen-nitrogen reactive radicals (RONS). High-energy electrons and key active species such as H2O2, ·OH, and O3 act on pollutant molecules in the wastewater, triggering a series of physicochemical reactions that destroy the molecular structure of the organic matter, ultimately degrading the wastewater.

[0059] The method provided in this embodiment utilizes a three-way dielectric barrier micro-discharge device. The device's insulating medium 8 is a quartz three-way tube with an outer diameter of 8.0 mm, a wall thickness of 1.0 mm, and a tube length of 50.0 mm. The device's high-voltage electrode 9 has an outer diameter of 3.5 mm, an inner diameter of 2.8 mm, and a tube length of 51.0 mm. Its bottom discharge end opening has a diameter of 1.0 mm and is coaxial with the insulating medium 8. The device's grounding electrode 10 is a sheet of copper foil measuring 12.0 × 4.0 × 0.2 mm. It adheres to the outer wall of the lower tube section 82 of the insulating medium 8, away from the upper tube section 81, and is connected to the ground terminal of the high-voltage power supply 1. A dielectric barrier discharge plasma is generated within the copper foil-covered area of ​​the three-way tube. The discharge voltage is 3.0 to 3.5 kV, and the pulse frequency is adjusted between 10.0 and 16.0 kHz.

[0060] The method for degrading organic wastewater using a liquid film reaction device based on dielectric barrier microplasma discharge comprises the following steps:

[0061] Step 1: Start the power supply 1 and deliver the discharge gas to the hollow cylinder 92 of the high-voltage electrode 9 in the dielectric barrier micro plasma reactor through the gas bottle 6. The discharge gas discharges through the dielectric barrier between the ground electrode 10 and the high-voltage electrode 9.

[0062] Step 2: The reaction liquid flows into the water delivery end of the liquid flow channel through the water delivery pipe at a certain flow rate, forming a relatively uniform water film passing through the gap of the insulating medium channel;

[0063] Step 3: After the reaction starts, samples are taken every 3 minutes.

[0064] The reaction liquid is an organic dye; after the sample is removed, the degradation concentration of the organic dye is measured using ultraviolet spectrophotometry. The flow rate of the reaction liquid in step 2 is 8.7 mL / min; the discharge gas in step 1 is argon, oxygen, nitrogen, and their mixed gas sources, with a flow rate of 6.0 L / min; the reaction time is 0 to 3.0 minutes, and the initial solution volume is 100.0 mL. Experimental results show that single gas sources: argon, oxygen, and nitrogen (preferably oxygen) have a degradation rate of 36.8%; mixed gas sources: argon / oxygen (preferably a ratio of 1:5) have a degradation rate of 34.1%; and mixed gas sources: nitrogen / oxygen (preferably a ratio of 1:5) have a degradation rate of 30.9%.

[0065] Example 4

[0066] Compared with Example 3, the difference of this embodiment is that: the dielectric barrier micro-discharge device uses a planar single dielectric barrier micro-discharge device, the insulating medium 8 is a sheet glass plate with a size of 40.0×25.0×1.0mm, the width of the flow channel 11 is 5mm, the high-voltage electrode 9 is a sheet copper foil with a size of 40.0×25.0×1.0mm, and a discharge gap of 3mm is provided between it and the ground electrode 10, and the plasma discharge uses an air environment.

[0067] Example 5

[0068] The present invention also provides a method for nitrogen fixation based on liquid film dielectric barrier microplasma discharge. At room temperature and pressure, N2, O2, air and water are used as raw materials. Deionized water in a liquid container is input into a dielectric barrier microdischarge device through a water pipe to form a relatively uniform flowing water film. High-energy electrons and active species such as H2O2, OH, and O3 generated during the dielectric barrier microdischarge process can enable reactions such as N2 dissociation that are not easy to occur under conventional conditions to proceed at room temperature and pressure, directly reacting to generate nitrate ions, nitrite ions and ammonium ions, thereby achieving a nitrogen fixation process under mild conditions.

[0069] Compared with Example 3, the difference of this embodiment is that the reaction liquid is deionized water, the discharge gases in step 1 are N2:O2 (1:4), N2:O2 (1:1), and N2:O2 (4:1), respectively. Based on ion chromatography detection of nitrate and nitrite in the samples, the nitrite concentrations are 0.47 mg / L, 0.45 mg / L, and 0.34 mg / L, respectively; the nitrate concentrations are 0.81 mg / L, 0.90 mg / L, and 0.94 mg / L, respectively; and the TN (total nitrogen) contents are 0.32 mg / L, 0.34 mg / L, and 0.31 mg / L, respectively.

[0070] Example 6

[0071] Compared with Example 5, the difference of this embodiment is that: the dielectric barrier micro-discharge device uses a planar single dielectric barrier micro-discharge device, the insulating medium is a sheet glass plate, the width of the flow channel is 5.0 mm, the high-voltage electrode is a sheet copper foil, and a 3.0 mm discharge gap is provided between the high-voltage electrode and the ground electrode, and an air environment is used to replace the gas supply system 2. Based on ion chromatography, the nitrate and nitrite in the sample are detected, and the nitrite concentration is 0.08 mg / L, the nitrate concentration is 2.05 mg / L, and the TN (total nitrogen) content is 0.49 mg / L.

[0072] In summary, the present invention provides a liquid film reaction device and method based on dielectric-barrier microplasma discharge. Using air and water as raw materials, the device can directly react to generate nitrate, nitrite, and ammonium ions at room temperature and pressure, achieving nitrogen fixation under mild conditions. It can also achieve carbon fixation and organic wastewater degradation. The device has a simple structure, a small size, readily available gas sources, low technical costs, fast reaction speed, and high energy efficiency. The products of the nitrogen and carbon fixation processes can be used for drip irrigation of crops, providing them with elements such as carbon and nitrogen, thereby promoting their growth.

[0073] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A liquid film reaction device based on dielectric barrier microplasma discharge, characterized in that: The device comprises a power supply, a dielectric barrier micro-discharge device, and a liquid input system; the dielectric barrier micro-discharge device comprises an insulating medium, a high-voltage electrode, and a grounding electrode, and the power supply is connected to the high-voltage electrode and the grounding electrode respectively; the liquid input system comprises a liquid container and a water pipe, and the liquid container is connected to the water inlet end of the dielectric barrier micro-discharge device via the water pipe; the dielectric barrier micro-discharge device is a three-way dielectric barrier micro-discharge device; The insulating medium of the three-way dielectric barrier micro-discharge device is a three-way tubular structure, and the high-voltage electrode is arranged inside the insulating medium; The insulating medium of the three-way dielectric barrier micro-discharge device includes an upper tube section and a lower tube section that are interconnected. The high-voltage electrode of the three-way dielectric barrier micro-discharge device includes a metal hollow cylinder and a hollow end head that are interconnected. The lower tube section of the insulating medium is a liquid flow channel, one side of which is a water inlet end and the other side is a water outlet end. The hollow end head of the high-voltage electrode is mounted on the upper tube section of the insulating medium and serves as the air inlet end of the dielectric barrier micro-discharge device. The hollow cylinder of the high-voltage electrode is located inside the upper tube section of the insulating medium and extends into the lower tube section of the insulating medium. The bottom of the hollow cylinder of the high-voltage electrode serves as the discharge end and is provided with an opening perpendicular to the direction of liquid flow. The grounding electrode is attached to the outer wall of the lower tube section of the insulating medium at one end away from the upper tube section. The device further includes a gas supply system, the gas supply system including an air pump, a gas bottle and a gas pipe, the air pump, the gas bottle and the gas pipe are connected by a tee pipe, the other end of the gas pipe is connected to the gas inlet end of the dielectric barrier micro-discharge device, and the gas pipe is provided with a gas flow meter; The discharge distance between the ground electrode and the high voltage electrode ranges from 1.0 to 10.0 mm.

2. The liquid film reaction device based on dielectric barrier microplasma discharge according to claim 1, characterized in that: The diameter of the hollow cylinder of the high-voltage electrode is in the range of 3.0 to 5.0 mm, and the diameter of the opening at the bottom discharge end of the hollow cylinder of the high-voltage electrode is in the range of 0.5 to 1.5 mm.

3. The liquid film reaction device based on dielectric barrier microplasma discharge according to claim 1 or 2, characterized in that: The power supply is a high-voltage power supply with an output voltage range of 1.0~5.0 kV; the grounding electrode is in a mesh, linear or sheet shape, closely attached to the outer wall of the insulating medium, and connected to the ground terminal of the high-voltage power supply; the material of the insulating medium is glass, quartz, ceramic or aluminum oxide, and the materials of the high-voltage electrode and the grounding electrode are copper, tin, aluminum, tungsten, titanium, stainless steel or metal alloy.

4. A method for fixing nitrogen, fixing carbon or degrading organic wastewater using a liquid membrane reaction device based on dielectric barrier microdischarge, characterized in that: The method uses a liquid film reaction device based on dielectric barrier microplasma discharge according to any one of claims 1 to 3, comprising the following steps: Step 1: Turn on the power supply and deliver the discharge gas into the hollow cylinder of the high-voltage electrode in the three-way dielectric barrier micro-discharge device through an air pump or gas bottle. The discharge gas generates dielectric barrier discharge between the ground electrode and the high-voltage electrode. Step 2: The reaction liquid flows into the water delivery end through the water delivery pipe to form a uniform water film and pass through the flow channel; Step 3: During the reaction, samples are taken regularly and the reaction liquid is replenished in time.

5. The method for fixing nitrogen, fixing carbon or degrading organic wastewater using a liquid membrane reaction device based on dielectric barrier microdischarge according to claim 4, characterized in that: The reaction liquid includes deionized water, pure water and an organic pollutant solution; the flow rate of the reaction liquid in step 2 is 5.0 to 20.0 mL / min; the discharge gas in step 1 is argon, oxygen, nitrogen, air or a mixture thereof, with a flow rate of 1.0 to 8.0 L / min; the discharge voltage is controlled to vary between 1.0 and 5.0 kV, and the pulse frequency is adjusted between 10.0 and 16.0 kHz.

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