Method for preparing plasma-activated water and preparation device

Abstract

The application belongs to the field of plasma-activated water preparation, and particularly relates to a preparation method and a preparation device of plasma-activated water. The method comprises placing a high-voltage electrode in a container containing a water solution to be activated. The bottom of the container is provided with an air inlet, the inside of the container is provided with a gas guide groove around the air inlet, and the high-voltage electrode is suspended in the gas guide groove. The top of the container is symmetrically provided with an even number of air outlets relative to the high-voltage electrode. An airflow is introduced into the bottom of the gas guide groove through the air inlet outside the container. Under the guidance of the gas guide groove, the airflow pushes the water solution away around the high-voltage electrode and flows out through the air outlets. At this time, a gas cavity is formed around the high-voltage electrode, and the height of the gas cavity satisfies that the area of the high-voltage electrode is completely not in contact with the water in the water cavity. The gas in the gas cavity is controlled to discharge to generate plasma and activate the water in the container. The application does not exist a conduction current outside the discharge loop between the high-voltage electrode and the ground electrode, thereby reducing the energy consumption of the preparation of the activated water.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of plasma-activated water preparation, and more particularly relates to a method and device for preparing plasma-activated water. BACKGROUND

[0002] Research shows that the plasma generated by gas discharge contains active components such as O3, NO, NO2, OH, and O. These active components will generate peroxynitrite, hydrogen peroxide, nitrous acid, and nitric acid in water after interacting with water. These substances have high oxidation-reduction potential and can effectively kill pathogens and degrade harmful substances. Therefore, plasma-activated water has great application prospects in sterilization and disinfection, fruit and vegetable cleaning, insurance, and sewage treatment.

[0003] The traditional method for preparing plasma-activated water is to first discharge in the gas phase and then pass the generated plasma into the liquid phase. The defect of this preparation method is that short-lived active particles in the plasma are quenched before interacting with the liquid phase. In view of the drawbacks of the traditional technology, researchers place two electrodes in water and use various technical means to generate a bubble channel between the two electrodes, and plasma discharge occurs along the bubble channel. Although the bubble channel method generates discharge in water and allows the generated plasma to fully contact the liquid phase, since both electrodes are in water, a large conduction current is generated in the liquid phase in addition to the discharge along the bubble channel, which greatly increases the energy consumption of plasma-activated water.

[0004] Therefore, there is a need for a technical means that can generate discharge in the liquid phase, improve the efficiency of plasma-activated water, and avoid direct conduction current between two electrodes to reduce the energy consumption of plasma-activated water. SUMMARY

[0005] In view of the defects and improvement needs of the prior art, the present application provides a method and device for preparing plasma-activated water, which aims to overcome the defect of increased energy consumption caused by conduction current between electrodes in the traditional bubble channel method of plasma-activated water.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a method for preparing plasma-activated water is provided, comprising:

[0007] A high-voltage electrode is placed in a container containing a water solution to be activated. The bottom of the container is provided with an air inlet, the inside of the container is provided with a gas guide groove around the air inlet, and the high-voltage electrode is suspended in the gas guide groove. An even number of air outlets are symmetrically arranged on the top of the container relative to the high-voltage electrode.

[0008] An air flow is introduced into the bottom of the air guide groove through the air inlet outside the container, and the air flow parameters and the container structure parameters satisfy: under the guidance of the air guide groove, the air flow is pushed away from the water solution along the periphery of the high-voltage electrode and flows out through the air outlet, at this time, an air cavity is formed around the high-voltage electrode, and the height of the air cavity satisfies that the area of the high-voltage electrode is completely not in contact with the water in the water cavity;

[0009] The high-voltage electrode is powered, the gas in the air cavity starts to discharge to generate plasma, and the water in the container is activated, so that the preparation of the plasma-activated water is realized.

[0010] Further, the air inlet is located at the center of the bottom of the air guide groove, and the high-voltage electrode is placed on the axis of the air guide groove.

[0011] The application also provides a preparation device of plasma-activated water for performing the preparation method of the plasma-activated water.

[0012] The bottom of the container is provided with an air inlet, the inside of the container is provided with an air guide groove around the air inlet, which is used for accommodating the high-voltage electrode and guiding the air flow to form an air cavity around the high-voltage electrode, and the top of the container is symmetrically provided with an even number of air outlets relative to the high-voltage electrode.

[0013] The air pump is used for introducing air into the air guide groove through the air inlet.

[0014] The discharge system comprises a high-voltage electrode and a cathode, the cathode is arranged in the water solution, and the high-voltage electrode is suspended in the air guide groove.

[0015] Further, a one-way valve is arranged on the air inlet, and the air flow is introduced into the bottom of the air guide groove outside the container through the one-way valve.

[0016] Further, the height of the air guide groove is much lower than the length of the high-voltage electrode, the high-voltage electrode and the insulating lead wire connecting the high-voltage electrode and the high-voltage power supply in the discharge system are wrapped by an insulating medium, the liquid level in the container is lower than the top of the container, the top position of the container surrounded by all the air outlets is designed as an air column cap which can be filled by the air flow, and the air flow changes the moving direction when moving upwards along the periphery of the high-voltage electrode to the air column cap and is discharged from the air outlet.

[0017] Further, the air column cap is in the shape of an umbrella.

[0018] Further, the air guide groove is in a circular columnar structure, and the inner side wall is in the shape of a spiral line.

[0019] Further, the height of the air guide groove is not less than the height of the high-voltage electrode suspended in the container; the sidewall of the air guide groove is uniformly provided with arrayed through holes; when the air flow moves upward along the periphery of the high-voltage electrode, the water flow around the high-voltage electrode is discharged from the air guide groove through the through holes.

[0020] Further, when the liquid level in the container is lower than the top of the container, the water flow around the high-voltage electrode is also discharged through the container space above the liquid level.

[0021] Overall, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0022] (1) The method proposed by the present application generates discharge in water, and the generated plasma directly contacts and interacts with the surrounding water, so that various active components in the plasma are fully absorbed by the water, and the efficiency of activated water preparation is high. In particular, the method of the present application generates a gas column around the high-voltage electrode, and the discharge occurs in the gas column. The height of the gas cavity satisfies that the region of the high-voltage electrode is completely not in contact with the water in the water cavity, so that there is no conduction current other than the discharge loop between the high-voltage electrode and the ground electrode, which greatly reduces the energy consumption in the process of preparing activated water.

[0023] (2) To realize the above method, the present application proposes two kinds of preparation devices for the discharge scenarios of high-voltage electrodes with medium wrapping and high-voltage electrodes without medium wrapping. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A flow chart of a preparation method of plasma activated water is provided for the embodiments of the present application;

[0025] Figure 2 A structure schematic diagram of a preparation device of plasma activated water is provided for the embodiments of the present application;

[0026] Figure 3 A structure schematic diagram of a gas column cap is provided for the embodiments of the present application;

[0027] Figure 4 A structure schematic diagram of another preparation device of plasma activated water is provided for the embodiments of the present application;

[0028] Figure 5 A structure schematic diagram of an air guide groove is provided for the embodiments of the present application.

[0029] In all the drawings, the same reference signs are used to represent the same elements or structures, wherein:

[0030] 1 is a high-voltage electrode, 2 is an insulated wire, 3 is a medium, 4 is a ground electrode, 5 is a high-voltage power supply, 6 is an air pump, 7 is an air inlet, 8 is a one-way valve, 9 is a gas guide groove, 10 is a gas cavity, 11 is a gas column cap, 12 is an air outlet, 13 is a water cavity, and 14 is a water outlet. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0032] Example 1

[0033] A method for preparing plasma-activated water, as shown in Figure 1 , comprising:

[0034] Placing a high-voltage electrode in a container containing a water solution to be activated, wherein the bottom of the container is provided with an air inlet, the inside of the container is provided with a gas guide groove around the air inlet, and the high-voltage electrode is suspended in the gas guide groove; the top of the container is symmetrically provided with an even number of air outlets relative to the high-voltage electrode;

[0035] An air flow is introduced into the bottom of the gas guide groove through the air inlet outside the container, and the air flow parameters and container structure parameters satisfy: under the guidance of the gas guide groove, the air flow pushes away the water solution around the high-voltage electrode and flows out through the air outlet, at this time a gas cavity is formed around the high-voltage electrode, and the height of the gas cavity satisfies that the area of the high-voltage electrode is completely not in contact with the water in the water cavity;

[0036] The high-voltage electrode is electrified, the gas in the gas cavity starts to discharge to generate plasma and activate the water in the container, and the preparation of plasma-activated water is realized.

[0037] There are at least two air outlets, the method proposed in this embodiment, the discharge occurs in the water, the generated plasma directly contacts and interacts with the surrounding water, various active ingredients in the plasma are fully absorbed by the water, the activated water preparation efficiency is high, in particular, the method generates a gas column around the high-voltage electrode, the discharge occurs in the gas column, the height of the gas cavity satisfies that the area of the high-voltage electrode is completely not in contact with the water in the water cavity, so that there is no conduction current between the high-voltage electrode and the ground electrode except the discharge loop, which greatly reduces the energy consumption in the process of preparing activated water.

[0038] As a preferred embodiment, the air inlet is located at the center of the bottom of the air guide groove, and the high-voltage electrode is placed on the axis of the air guide groove, so as to ensure that the air cavity formed is a regular circular cylinder or a square body, and the specific shape of the regular shape is determined by the shape surrounded by the air guide groove and the high-voltage electrode.

[0039] Embodiment two

[0040] A device for preparing plasma-activated water is used to perform the method for preparing plasma-activated water as described in Embodiment one above, and comprises a container, a discharge system, and a gas pump.

[0041] The bottom of the container is provided with an air inlet, and an air guide groove is arranged around the air inlet in the interior of the container, for accommodating a high-voltage electrode and guiding the airflow to form an air cavity around the high-voltage electrode; an even number of air outlets are symmetrically arranged on the top of the container relative to the high-voltage electrode; the gas pump is used to ventilate the air guide groove through the air inlet; the discharge system comprises the high-voltage electrode and a ground electrode, the ground electrode is arranged in the water solution, and the high-voltage electrode is suspended and placed in the air guide groove.

[0042] The device directly uses water as the ground electrode, and the discharge occurs in a small gap between the high-voltage electrode and the water, so that the required discharge voltage is low.

[0043] As a preferred embodiment, a one-way valve is arranged on the air inlet, and the airflow is introduced into the bottom of the air guide groove through the one-way valve outside the container.

[0044] In addition, the material of the high-voltage electrode can be a good conductor, which can be stainless steel, tungsten, copper, etc., directly inserted into the medium tube, and then filled with conductive glue or soldering tin to fill the entire medium tube, or the conductive glue or soldering tin can be directly used to fill the medium tube.

[0045] The insulating wire is an insulating wire with a withstand voltage of 30 kV, one end of which is inserted into the medium tube and connected with the high-voltage electrode, the other end of which is connected with the high-voltage power supply, and the gap between the insulating wire and the medium tube is filled with an insulating filler. The insulating filler includes but is not limited to epoxy resin glue, silicone glue, etc.

[0046] The material of the ground electrode is a good conductor, which can be stainless steel, tungsten, copper, carbon, etc., and the ground electrode is directly inserted into the water cavity and directly grounded.

[0047] The high-voltage power supply can be implemented as an alternating current power supply or a pulse power supply.

[0048] The gas pump can be any pump that can provide a gas flow rate of more than 50 L / min.

[0049] The one-way valve on the air inlet of the container is any structure that can realize one-way transmission of fluid, and the simplest implementation is a one-way movable rubber plug with good sealing performance.

[0050] The air outlet can serve as both a gas outlet and a water inlet, and is formed by opening a hole at the top of the activated water device.

[0051] The container can also be equipped with a water outlet, which is used to release the activated water from the cavity. The outlet is located at the bottom of the water activation device.

[0052] To achieve the above solution, the following device is specifically provided:

[0053] Device 1: such as Figure 2 As shown, Figure 2 The medium and high voltage electrodes, along with the insulated wires connecting the high voltage electrodes to the high voltage power supply in the discharge system, are all wrapped in an insulating medium; the height of the gas guide groove is much lower than the length of the high voltage electrode; the liquid level in the container is lower than the top of the container; the top of the container, surrounded by all the gas outlets, is designed as a gas column cap that can be filled by airflow (structure as follows). Figure 3 As shown, the airflow moves upwards along the high-voltage electrode and changes direction when it reaches the air column cap, exiting from the outlet.

[0054] Preferably, the air column cap is umbrella-shaped, which results in a more uniform air column size.

[0055] Preferably, the air guide groove has a circular cylindrical structure with a spiral shape on its inner sidewall, which makes the air column thinner, that is, the airflow adheres better to the high-voltage electrode, and the resulting air cavity is thinner.

[0056] The high-voltage electrode 1 and the dielectric 3 (an insulating material) form a dielectric barrier discharge structure. It is connected to the high-voltage power supply 5 via an insulated wire 2, which passes through the gas column cap 11 and is fixed to it using insulating filler, such as epoxy resin potting compound or silicone sealant. The ground electrode 4 is a good conductor, directly inserted into the water cavity and grounded. The high-voltage power supply 5 uses a pulse power supply or AC power. The air pump 6 generates high-velocity gas to inject into the device. The air inlet 7 is the channel for injecting high-velocity gas into the device. The one-way valve 8 allows gas to be injected from outside the device into the device, while preventing water from flowing out. The air guide groove 9 guides the direction of the high-velocity gas flow, allowing it to move around the high-voltage electrode. The gas cavity 10 is formed by the high-velocity gas displacing water. The gas column cap 11 guides the high-velocity gas to diffuse to both sides, preventing it from leaving the liquid surface directly as bubbles. The air outlet 12 releases the gas entering the device and also serves as a water inlet for adding water. The water chamber 13 serves as a container for holding water within the activated water device. The activated water is released from the chamber through the outlet 14.

[0057] Dielectric 3 serves as the dielectric barrier for discharge, covering the high-voltage electrode. Its materials include, but are not limited to, ceramics, quartz, and glass. Its shape is tubular, such as round or square tubes.

[0058] The gas column cap 11 functions to guide the high flow rate gas to diffuse to the container-removing area on both sides of the high voltage, without directly escaping upward in the form of bubbles, and can be implemented in the shape of an umbrella, an inverted cone, or a flat plate, among which the umbrella shape is preferable.

[0059] In the device, the specific high voltage electrode 1 is a copper column with a diameter of 3 mm and a length of 4 cm, and the gap between the high voltage electrode 1 and the medium 3 is filled with molten solder; the insulated wire 2 is a high voltage wire with a withstand voltage of 30 kV, and one end is welded to the high voltage electrode 1 and the other end is connected to the high voltage power supply 5, which is implemented as an alternating current power supply with an amplitude of 20 kV and a frequency of 30 kHz. The gas flow rate of the air pump 6 is set to 100 L / min, and the one-way valve 8 is implemented as a rubber one-way plug with good sealing performance. The gas guide groove 9 is implemented as a cylindrical tubular structure, and the gas column cap 11 is implemented as an umbrella-shaped structure, forming a gas cavity 10 with a thickness of 2 mm. The water level in the water cavity 13 is 5 cm, and the water surface is higher than the high voltage electrode 1.

[0060] The air pump 6 introduces high flow rate gas into the water cavity 13 pre-filled with water through the one-way valve 8, completely displaces the water around the high voltage electrode and forms a gas cavity, and the water in the water cavity 13 is grounded through the ground electrode 4 inserted into the water cavity 13. Under the action of the high voltage power supply 5, dielectric barrier discharge occurs between the high voltage electrode 1 and the water cavity 13, and plasma is generated. Since the high voltage electrode is located below the water surface, the plasma is completely placed in the water environment when it is generated, and the short-lived active particles in the plasma can rapidly interact with the water at the gas-liquid interface to generate activated water. At the same time, since there is no direct contact between the high voltage electrode and the water, there is no conduction current other than the discharge current, and the energy consumption for generating activated water is low.

[0061] In addition, the activated water experiment can also be carried out under the following conditions: the high voltage power supply is an alternating current power supply with a frequency of 30 kHz and an amplitude of 20 kV. The air pump flow rate is 200 L / min. The gas guide groove is cylindrical and made of polytetrafluoroethylene (easy to process, qualified insulation, and resistant to chemical corrosion). The gas column cap is umbrella-shaped and made of polytetrafluoroethylene. The gas cavity is circular cylindrical with a thickness of 3 mm.

[0062] Device two: as shown in Figure 4 The height of the gas guide groove is not less than the height of the high voltage electrode suspended in the container; the side walls of the gas guide groove are uniformly provided with array through holes (structure as shown in Figure 5 When the gas flow moves upward around the high voltage electrode, the water flow around the high voltage electrode is discharged from the gas guide groove through the through holes, and when the liquid level in the container is lower than the top of the container, the water flow around the high voltage electrode is also discharged through the space above the liquid level in the container.

[0063] It should be noted that when the gas guide groove is below the liquid surface, the high-voltage electrode below the liquid surface is wrapped with insulating material to prevent the high-voltage electrode from directly contacting the aqueous solution.

[0064] In the device, the specific high-voltage electrode 1 is a copper column with a diameter of 1 m and a length of 5 m, the insulating wire 2 is a high-voltage wire with a withstand voltage of 30 kV, and one end is welded with the high-voltage electrode 1 and the other end is connected with the high-voltage power supply 5, which is implemented as a direct current power supply with an amplitude of 20 kV. The high-voltage electrode is located at the axis of the gas guide groove 9 and is coaxially installed with the gas guide groove 9, and the gas guide groove 9 is partially placed in the water cavity 13. The gas pump 6 is set to a gas flow rate of 100 L / min, and the gas is blown into the gas guide groove 9 through the gas inlet 7, which discharges all the water in the gas guide groove 9, forming a gas cavity between the high-voltage electrode 1 and the gas guide groove 9. The water in the water cavity 13 is grounded through the ground electrode 4 inserted into the water cavity 13, and under the action of the high-voltage power supply 5, discharge occurs between the high-voltage electrode 1 and the water cavity 13 and plasma is generated.

[0065] Since the discharge area is below the water surface, when the plasma is generated, it is completely placed in the water environment, and the short-lived active particles in the plasma can rapidly interact with the water at the gas-liquid interface to generate activated water. At the same time, since there is no direct contact between the high-voltage electrode and the water, there is no conduction current other than the discharge current, and the energy consumption for generating activated water is low.

[0066] It should be noted that device one is used for the scenario of wrapping the high-voltage electrode with a medium, and device two can be used for both the scenario of wrapping the high-voltage electrode with a medium and the scenario of not wrapping the high-voltage electrode with a medium.

[0067] In general, the core of the present application is to use gas flow to expel water near the electrode underwater and generate plasma by discharging between water and electrode.

[0068] Those skilled in the art will readily understand that the above description is only a preferred embodiment of the present application and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A device for preparing plasma-activated water, characterized in that, include: Containers, discharge systems, and air pumps; The container has an air inlet at the bottom and an air guide groove inside the container around the air inlet to accommodate the high-voltage electrode and guide the airflow to form an air cavity around the high-voltage electrode. There is no direct contact between the high-voltage electrode and the water. The top of the container has an even number of air outlets symmetrically arranged relative to the high-voltage electrode. The air pump is used to supply air to the air guide groove through the air inlet; The discharge system includes a high-voltage electrode and a cathode, the cathode being disposed in an aqueous solution, and the high-voltage electrode being suspended within the gas guide groove; The height of the gas guide groove is much lower than the length of the high-voltage electrode. The gas guide groove has a circular cylindrical structure with a spiral shape on its inner sidewall. The high-voltage electrode and the insulated wire connecting the high-voltage electrode to the high-voltage power supply in the discharge system are wrapped together with an insulating medium. The liquid level in the container is lower than the top of the container. The top of the container, surrounded by all the gas outlets, is designed as a gas column cap that can be filled by airflow. When the airflow moves upward along the high-voltage electrode to the gas column cap, it changes its direction of movement and is discharged from the gas outlet. Alternatively, the height of the air guide groove is not lower than the height at which the high-voltage electrode is suspended in the container; the sidewall of the air guide groove is uniformly provided with an array of through holes; when the airflow moves upward along the periphery of the high-voltage electrode, the water around the high-voltage electrode is completely discharged from the air guide groove through the through holes, forming a gas cavity between the high-voltage electrode and the air guide groove. This preparation apparatus is used to perform the following method for preparing plasma-activated water: A high-voltage electrode is placed inside a container containing an aqueous solution to be activated. The high-voltage electrode is suspended in the gas guide groove. An airflow is introduced from outside the container through the air inlet to the bottom of the gas guide groove. The airflow parameters and container structural parameters satisfy the following: Under the guidance of the gas guide groove, the airflow displaces the aqueous solution around the high-voltage electrode and flows out through the air outlet. At this time, a gas cavity is formed around the high-voltage electrode, and the height of the gas cavity is such that the area of ​​the high-voltage electrode does not come into contact with the water in the water cavity at all. When the high-voltage electrode is energized, the gas in the gas cavity begins to discharge, generating plasma and activating the water in the container, thereby realizing the preparation of plasma-activated water.

2. The preparation apparatus according to claim 1, characterized in that, The air inlet is located at the bottom center of the air guide groove, and the high-voltage electrode is placed on the axis of the air guide groove.

3. The preparation apparatus according to claim 1, characterized in that, A one-way valve is provided on the air inlet, and airflow is introduced into the bottom of the air guide groove through the one-way valve outside the container.

4. The preparation apparatus according to claim 1, characterized in that, The air column cap is umbrella-shaped.

5. The preparation apparatus according to claim 1, characterized in that, When the liquid level in the container is lower than the top of the container, the water around the high-voltage electrode is also drained through the container space above the liquid level.

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