Low-temperature plasma activated water preparation system, preparation method and application

Abstract

According to the low-temperature plasma activated water preparation system, the preparation method and the application, a direct-current voltage-driven air jet plasma generation device which is small and convenient and does not need a complex gas circuit is utilized in the preparation system, and air is adopted as working gas to treat an aqueous solution; an aqueous solution rich in active oxygen, active nitrogen and other active ingredients is efficiently generated, and the active ingredients have high oxidation-reduction potential and can effectively degrade PhSMe. The concentration of active particles in PAW is improved by optimizing the discharge voltage, the discharge time and the concentration of the sodium molybdate solution, so that the degradation effect of PhSMe is improved. An auxiliary agent sodium molybdate is introduced in the degradation process, and the degradation effect is two times higher than the pure PAW treatment effect.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental chemistry, and particularly relates to a low-temperature plasma activated water preparation system and method and application in the degradation of a chemical agent simulant thioanisole. Background Art

[0002] As an emerging technology, low-temperature plasma can generate a large number of active species, such as ozone (O3), atomic oxygen (O), hydrogen peroxide (H2O2), superoxide (O2-), reactive oxygen free radicals (ROS), etc. These active particles can undergo redox reactions with pollutants, thereby achieving the degradation of pollutants. Plasma technology is applied to the removal of pollutants, which can generally be achieved through two methods: direct contact between plasma and pollutants, and indirect treatment by preparing activated aqueous solutions. The former is mostly used in scenarios where the decontamination equipment is in direct contact with pollutants, and uses the combined effects of high-energy electrons, metastable particles and long-lived particles in the plasma on pollutants; the latter is often used in scenarios where the decontamination equipment cannot be in direct contact with pollutants, and uses the hydroxyl radicals, singlet oxygen and long-lived particles present in the plasma-activated solution to indirectly treat pollutants.

[0003] Plasma activated water (PAW) refers to an aqueous solution that has been treated with plasma. During the discharge process, plasma produces a large number of active substances and charged particles. These active particles can react with the liquid at the gas-liquid interface and produce secondary reaction substances, such as hydroxyl radicals, excited nitrogen molecules, atomic oxygen, etc., which enter the water by dissolving and reacting with water molecules, forming a series of active particles with relatively long lifespans, such as NO2 - 、NO3 - 、H + 、H2O2、O3、peroxynitrite (ONOO - ) etc. After removing the plasma device, these active particles can continue to react with each other in the liquid phase (such as H2O2 can react with NO2 - The reaction produces ONOO - ), forming a complex active particle system with excellent oxidative activity and bactericidal effects. In recent years, PAW has attracted increasing attention in the fields of industry, agriculture, medicine, and the environment as a new, efficient, and green bactericidal disinfectant.

[0004] Thioanisole (PhSMe) is an organic compound with a structure and solubility similar to mustard gas and is commonly used as a mustard gas simulant. Furthermore, it is a ubiquitous volatile pollutant in the environment. Due to its stable chemical structure, PhSMe is difficult to rapidly degrade by microorganisms, resulting in long-term residues in water bodies, posing a threat to drinking water safety and even accumulating in humans through the food chain. Under conditions of light or atmospheric oxidation, it may react with other pollutants to form secondary pollutants, exacerbating the risk of acid rain or photochemical smog. It can also adsorb onto soil particles, inhibiting soil microbial activity, affecting nutrient cycling, and negatively impacting plant growth. PhSMe residues in the environment can have a ripple effect on entire ecosystems, leading to a decline in biodiversity and impaired ecosystem function. Traditional methods for degrading PhSMe include high-temperature incineration, chemical neutralization, and oxidation. However, these methods suffer from poor decontamination efficiency, secondary pollution, and high costs. Therefore, the development of gentler, more environmentally friendly, and more effective purification methods is urgent. Summary of the Invention

[0005] (1) Technical issues to be resolved

[0006] The present invention proposes a low-temperature plasma-activated water preparation system, preparation method and application to solve the technical problem of how to simplify the plasma-activated water preparation process and achieve effective degradation of PhSMe.

[0007] (2) Technical solution

[0008] In order to solve the above technical problems, the present invention proposes a low-temperature plasma-activated water preparation system, which includes a high-voltage DC power supply and an air jet plasma generator; wherein the high-voltage DC power supply serves as a low-temperature plasma power supply; the air jet plasma generator internally includes a high-voltage resistor and a discharge medium, one end of the high-voltage resistor is connected to the high-voltage DC power supply, and the other end is connected to the discharge medium. Under the drive of the high-voltage DC power supply, the discharge medium generates plasma in the form of corona discharge.

[0009] Furthermore, the air jet plasma generating device is a cylindrical structure, and the interior of the cylinder includes multiple high-voltage resistors and discharge media distributed in a circular shape. Each group of high-voltage resistors and discharge media constitutes a discharge unit, and multiple discharge units are arranged in the form of a circular array to form a plasma array.

[0010] Furthermore, the air jet plasma generating device fixes the relative positions of the discharge medium and the high-voltage resistor through the tubular resin material, and fills the tubular resin material with epoxy resin.

[0011] Furthermore, the discharge medium is a tungsten needle electrode.

[0012] Furthermore, the diameter of the tungsten needle electrode is 0.5 mm, the length is 30 mm, and the tip curvature radius is 50 μm.

[0013] Furthermore, the air jet plasma generator has a length of 15 cm, a diameter of 6 cm, and a processing area of ​​700 mm 2 .

[0014] In addition, the present invention also proposes a method for preparing low-temperature plasma-activated water, which uses the above-mentioned low-temperature plasma-activated water preparation system, including: placing an ethanol aqueous solution in a culture dish, leading a wire out of the aqueous solution and grounding it, placing the culture dish directly below an air jet plasma generator, turning on a high-voltage direct current power supply, the air jet plasma generator generates plasma, and performing a discharge treatment on the ethanol aqueous solution in the culture dish to prepare low-temperature plasma-activated water.

[0015] Furthermore, the ethanol aqueous solution is a 5% ethanol solution, the high-voltage DC power supply voltage is 6 to 10 kV, and the discharge time is 5 to 20 minutes.

[0016] In addition, the present invention also proposes a method for degrading thioanisole by low-temperature plasma-activated water. The method comprises mixing thioanisole, Na2MoO4 and plasma-activated water, using Na2MoO4 as an auxiliary solution for activated water, and achieving degradation of PhSMe after the reaction.

[0017] Furthermore, the mass concentration of thioanisole is 0.1 mg / mL, and the molar concentration of Na2MoO4 is 0.1-0.9 mol / L.

[0018] (3) Beneficial effects

[0019] The present invention proposes a low-temperature plasma-activated water preparation system, preparation method, and application. This preparation system utilizes a compact, convenient, DC voltage-driven air jet plasma generator that does not require complex gas circuits. Air is used as the working gas to treat aqueous solution, efficiently producing an aqueous solution rich in active ingredients such as reactive oxygen and reactive nitrogen. These active ingredients have high redox potentials and are capable of effectively degrading PhSMe. By optimizing the discharge voltage, discharge time, and sodium molybdate solution concentration, the concentration of active particles in the PAW is increased, thereby enhancing the degradation of PhSMe. The inclusion of sodium molybdate as an additive during the degradation process results in a degradation effect that is twice as effective as that achieved by simple PAW treatment.

[0020] The plasma-activated water prepared by the present invention is easy to transport and carry, suitable for outdoor use and for cleaning pipeline equipment, etc., and can effectively solve the problems of traditional plasma equipment being bulky and inconvenient to carry, greatly expanding the application range of plasma technology. By combining plasma-activated water with an auxiliary agent, not only can the disinfection effect of the activated water be improved, but its ability to degrade complex poisons can also be enhanced, providing a more efficient and convenient solution for environmental protection and pollution control. The present invention can discharge directly in the air, and does not require additional gas or rare gas, which is convenient for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the low-temperature plasma activated water preparation system of the present invention;

[0022] Figure 2 The effect of different discharge voltages on the degradation rate of PhSMe;

[0023] Figure 3 The effect of different discharge times on the degradation rate of PhSMe;

[0024] Figure 4 The effect of different Na2MoO4 concentrations on the degradation rate of PhSMe. DETAILED DESCRIPTION

[0025] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the accompanying drawings and examples.

[0026] The present invention proposes a low-temperature plasma activated water preparation system, which comprises the following components: Figure 1 As shown, it mainly includes a high-voltage DC power supply and an air jet plasma generating device.

[0027] A high voltage DC power supply is used as a low temperature plasma power supply.

[0028] The air jet plasma generator is a cylindrical structure, 15 cm long and 6 cm in diameter. Inside the cylinder are multiple high-voltage resistors (100 MΩ) arranged in a circular pattern. One end of each resistor is connected to a high-voltage DC power supply, and the other end is welded to the discharge medium. The discharge medium uses tungsten needle electrodes, which are fixed relative to the high-voltage resistors by a tubular resin material. The tubular resin material is filled with epoxy resin, ensuring excellent safety during discharge.

[0029] The diameter of the tungsten needle electrode is 0.5mm, the length is 30mm, and the curvature radius of the needle tip is 50μm. Each set of high-voltage resistors and tungsten needle electrodes constitutes a discharge unit. Multiple discharge units are arranged in a circular array to form a plasma array. Driven by a high-voltage DC power supply, the tungsten needle electrodes generate plasma in the form of corona discharge. The processing area of ​​the air jet plasma generator is 700mm 2 The high-voltage resistor limits the discharge current and can effectively prevent the stable glow discharge from transforming into spark discharge.

[0030] The method for preparing plasma-activated water using the above-mentioned low-temperature plasma-activated water preparation system is as follows: a low-concentration ethanol aqueous solution (5% ethanol solution) is placed in a plastic culture dish, a wire is led out of the aqueous solution and grounded, an air jet plasma array device driven by a direct current voltage is used, the culture dish is placed directly below the air jet plasma generator, a high-voltage direct current power supply is turned on, the voltage parameter is adjusted to 10kV, a plasma is generated, and the low-concentration ethanol aqueous solution in the plastic culture dish is subjected to a discharge treatment for 5 to 20 minutes to prepare plasma-activated water (PAW).

[0031] The prepared plasma-activated water was used to degrade the chemical agent simulant thioanisole. The degradation method was as follows: thioanisole PhSMe (concentration of 0.1 mg / mL), Na2MoO4 (0.1-0.9 mol / L) and plasma-activated water were mixed, and Na2MoO4 was used as an auxiliary solution for the activated water. The mixture was reacted for a period of time to achieve the degradation of PhSMe.

[0032] Turn off the high-voltage DC power supply, take out the activated aqueous solution and perform extraction treatment (treatment conditions: add 4 mL of cyclohexane, shake for 1 minute to complete the extraction, and then let it stand for 8 minutes); extract 1 mL of the extracted organic supernatant, inject it into a 2 mL chromatographic bottle, and use gas chromatography (GC) to detect the content.

[0033] Adjust the high-voltage DC power supply to 6-10 kV, discharge the ethanol aqueous solution for 15 minutes, then turn off the power and take out the activated aqueous solution. Take a PhSMe solution with a mass concentration of 0.1 mg / mL and add it to a 15 mL threaded round-bottom centrifuge tube, add a Na2MoO4 solution with a concentration of 0.3 mol / L, add the plasma-activated aqueous solution, place it in a constant temperature oscillating mixer and mix for 30 minutes, then perform the extraction operation, add 4 mL of cyclohexane, oscillate for 1 minute, and then let it stand for 8 minutes to allow the solution to separate. Take 1 mL of the organic layer clear liquid, filter it through a 0.22 μm organic filter, and inject it into a 2 mL chromatographic bottle. GC analysis was used to calculate the concentration of the substrate after extraction. The effect of different discharge voltages on the degradation rate of PhSMe is shown below. Figure 2 shown.

[0034] Adjust the voltage of the high-voltage DC power supply to 10kV, discharge the ethanol-water solution for 5 to 20 minutes, then turn off the power and take out the activated water solution. Take a PhSMe solution with a mass concentration of 0.1 mg / mL and add it to a 15mL threaded round-bottom centrifuge tube, add 0.3mol / L Na2MoO4 solution, add the plasma-activated water solution, and place it in a constant temperature oscillating mixer to mix for 30 minutes. Then perform the extraction operation, add 4mL of cyclohexane, oscillate for 1 minute, and then let it stand for 8 minutes to allow the solution to separate. Take 1mL of the organic layer clear liquid, filter it through a 0.22μm organic filter, and inject it into a 2mL chromatographic bottle. GC analysis was used to calculate the concentration of the substrate after extraction. The effect of different discharge times on the degradation rate of PhSMe is shown below. Figure 3 shown.

[0035] Adjust the voltage of the high-voltage DC power supply to 10kV, discharge the ethanol aqueous solution for 15 minutes, then turn off the power and take out the activated aqueous solution. Take a PhSMe solution with a mass concentration of 0.1 mg / mL and add it to a 15mL threaded round-bottom centrifuge tube, add a Na2MoO4 solution with a concentration of 0-0.9 mol / L, add the plasma-activated aqueous solution, place it in a constant temperature oscillating mixer and mix it for 30 minutes, then perform the extraction operation, add 4mL of cyclohexane, oscillate for 1 minute, and then let it stand for 8 minutes to allow the solution to separate. Take 1mL of the organic layer clear liquid, filter it through a 0.22μm organic filter, and inject it into a 2mL chromatographic bottle. GC analysis was used to calculate the substrate concentration after extraction. The effect of different Na2MoO4 concentrations on the degradation rate of PhSMe is shown below. Figure 4 shown.

[0036] GC analysis was used to measure and calculate the concentration of the extracted substrate. The calculation formula is:

[0037]

[0038] Where D is the degradation rate of the substrate by activated water; C is the concentration of the substrate after treatment with activated water; C0 is the concentration of the substrate without treatment with activated water, and the unit of concentration is mg / mL.

[0039] like Figure 2 As shown in the figure, when preparing activated water, the degradation rate gradually increases with the increase of discharge voltage. The degradation rate increases most significantly when the voltage is 7-9kV, and the discharge voltage is finally determined to be 10kV. Figure 3 As shown in the figure, under the condition of 10 kV, the degradation rate of PhSMe increases with the increase of discharge time when preparing activated water, and the degradation rate of PhSMe reaches the highest at 15 min. Figure 4 As shown in the figure, the concentration of added Na2MoO4 will also affect the degradation rate. Based on the considerations of economy and efficiency, the concentration of Na2MoO4 was finally determined to be 0.3 mol / L.

[0040] In summary, at a voltage of 10 kV, 5% ethanol water was discharged for 15 minutes to prepare plasma-activated water; after 30 minutes of reaction, the degradation rate of PhSMe by the PAW / Na2MoO4 system reached 98.6%.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low-temperature plasma activated water preparation system, characterized in that: The low-temperature plasma-activated water preparation system includes a high-voltage direct current power supply and an air jet plasma generator; wherein the high-voltage direct current power supply serves as a low-temperature plasma power supply; the air jet plasma generator internally includes a high-voltage resistor and a discharge medium, one end of the high-voltage resistor is connected to the high-voltage direct current power supply, and the other end is connected to the discharge medium, and under the drive of the high-voltage direct current power supply, the discharge medium generates plasma in the form of corona discharge.

2. The low-temperature plasma activated water preparation system according to claim 1, wherein The air jet plasma generator is a cylindrical structure, and the interior of the cylinder includes multiple high-voltage resistors and discharge media distributed in a circular shape. Each group of high-voltage resistors and discharge media constitutes a discharge unit, and multiple discharge units are arranged in the form of a circular array to form a plasma array.

3. The low-temperature plasma activated water preparation system according to claim 1, wherein The air jet plasma generating device fixes the relative positions of the discharge medium and the high-voltage resistor through a tubular resin material, and epoxy resin is filled inside the tubular resin material.

4. The low-temperature plasma activated water preparation system according to claim 1, wherein The discharge medium is a tungsten needle electrode.

5. The low-temperature plasma activated water preparation system according to claim 1, wherein: The tungsten needle electrode has a diameter of 0.5 mm, a length of 30 mm, and a tip curvature radius of 50 μm.

6. The low-temperature plasma activated water preparation system according to claim 1, wherein: The air jet plasma generator has a length of 15 cm, a diameter of 6 cm, and a treatment area of ​​700 mm 2 .

7. A method for preparing low-temperature plasma activated water, characterized in that: The low-temperature plasma-activated water preparation system according to any one of claims 1 to 6 comprises the following steps: placing an ethanol aqueous solution in a culture dish, leading a wire out of the aqueous solution and grounding it, placing the culture dish directly below an air jet plasma generator, turning on a high-voltage DC power supply, causing the air jet plasma generator to generate plasma, and performing a discharge treatment on the ethanol aqueous solution in the culture dish to prepare low-temperature plasma-activated water.

8. The method for preparing low-temperature plasma activated water according to claim 7, wherein: The ethanol aqueous solution is a 5% ethanol solution, the voltage of the high-voltage DC power supply is 6-10 kV, and the discharge time is 5-20 minutes.

9. A method for degrading thioanisole by low-temperature plasma activated water, characterized in that: The method comprises the following steps: mixing thioanisole, Na2MoO4 and plasma-activated water, using Na2MoO4 as an auxiliary solution of the activated water, and achieving degradation of PhSMe after the reaction.

10. The method for degrading thioanisole by low-temperature plasma activated water according to claim 9, wherein: The mass concentration of thioanisole is 0.1 mg / mL, and the molar concentration of Na2MoO4 is 0.1-0.9 mol / L.

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