A method for plasma degradation of chemical warfare agents and its application

Abstract

This invention relates to the field of drinking water disinfection technology, and more particularly to a method for plasma degradation of chemical warfare agents and its application. The method includes: placing a titanium dioxide carrier loaded with manganese oxide in a chemical warfare agent medium as a reaction medium; setting a DBD plasma generator pointing towards the reaction medium; the DBD plasma generator driving plasma towards the reaction medium through an electric field; and using singlet oxygen and superoxide anions generated by the reaction medium, or singlet oxygen, superoxide anions, and hydroxyl radicals generated by the reaction medium and the chemical warfare agent medium together, to degrade the chemical warfare agent in the chemical warfare agent medium. This invention achieves effective degradation and decontamination of chemical warfare agents by combining DBD plasma technology with a metal oxide catalyst, and can more effectively and thoroughly remove the pollution caused by chemical warfare agents to the gaseous and liquid environments, with the advantages of high efficiency and thoroughness.

Description

Technical Field

[0001] This invention relates to the field of drinking water disinfection technology, and in particular to a method for plasma degradation of chemical warfare agents and its application. Background Technology

[0002] Chemical warfare agents are various chemical substances widely used for warfare purposes, possessing high toxicity and capable of causing large-scale casualties. They are typically characterized by high toxicity, rapid action, and long-lasting effects. Based on their toxic properties, they can be broadly classified into: nerve agents (N-type) such as sarin and tabun (organophosphatic acid compounds); blistering agents (B-type) such as mustard gas and nitrogen mustard (putrefactive agents); systemic agents (S-type) such as hydrocyanic acid and hydrogen chloride (which disrupt cellular respiration); and asphyxiating agents (C-type) such as phosgene and diphosgene (which act on the respiratory system).

[0003] Chemical warfare agents come in many varieties, exhibiting different characteristics, and generally possess persistent effects and are prone to causing environmental residues. Therefore, the degradation and removal of chemical warfare agents has always been a challenging problem in the field of pollution control.

[0004] Most technologies for addressing this issue involve steam washing to remove chemical warfare agents. A commonly used method involves mixing ammonia or other nitrogen-containing compounds with hydrogen peroxide vapor to chemically remove the contaminants, rendering them harmless. This process primarily utilizes the strong oxidizing properties of hydrogen peroxide to oxidize and decompose the chemical warfare agents, with byproducts including only oxygen and water vapor, which do not cause secondary pollution. However, these methods are slow, typically requiring 24 hours or more, necessitating a certain concentration of hydrogen peroxide vapor, and are greatly affected by environmental factors; for example, wind speed in outdoor environments significantly impacts the actual degradation effect.

[0005] Furthermore, steam is insufficient for cleaning complex environments and equipment. Therefore, plasma degradation cleaning technology has been gradually developed. Plasma degradation cleaning is a comprehensive treatment technology. Compared with steam treatment, its decontamination and degradation capabilities are significantly enhanced, and it is unaffected by environmental factors such as dust obstruction and wind. It has strong adaptability, requires no consumables, and leaves no chemical residues. It can effectively decontaminate air, surfaces of complex objects, and aquatic environments, and is harmless to humans, possessing general advantages. However, its drawback lies in its ability to essentially cover the discharge area. The effective treatment area is significantly limited, thus restricting its application in the degradation of chemical warfare agents. Summary of the Invention

[0006] To address the limitations of existing chemical warfare agent treatment methods and the significant limitations of existing plasma treatment technologies for chemical warfare agent degradation, this invention provides a method for plasma degradation of chemical warfare agents, as well as the application of this method.

[0007] The main advantages of this invention are:

[0008] First, it can effectively degrade chemical warfare agents based on DBD plasma decontamination technology combined with the use of reactive media, resulting in a larger effective area;

[0009] Second, it is safe to use, has high degradation and disinfection efficiency, and produces no toxic or side effects.

[0010] To achieve the above objectives, the present invention adopts the following technical solution.

[0011] In a first aspect, the present invention provides a method for plasma degradation of chemical warfare agents.

[0012] A titanium dioxide carrier loaded with manganese oxide is placed in a chemical warfare agent medium as a reaction medium. A DBD plasma generator is set to point towards the reaction medium, and the distance between the emitter of the DBD plasma generator and the surface of the reaction medium is controlled to be 10-35 mm. The DBD plasma generator drives the plasma toward the reaction medium through an electric field. The chemical warfare agent in the chemical warfare agent medium is degraded by singlet oxygen and superoxide anions generated by the reaction medium, or by singlet oxygen, superoxide anions and hydroxyl radicals generated by the reaction medium and the chemical warfare agent medium.

[0013] In the technical solution of this invention, the mature DBD plasma decontamination technology is first combined. A DBD plasma generating device first generates plasma, which can decontaminate chemical warfare agents (i.e., the environmental medium in which the chemical warfare agent is located) to a certain extent. However, the decontamination capacity is relatively limited, and most common plasma discharge devices cannot effectively achieve area-wide decontamination, resulting in relatively low decontamination efficiency. Literature such as "Sterilizing processes and mechanisms for treatment of Escherichia coli with dielectric-barrier discharge plasma" [J] and "Observation of the transition from a Townsend discharge to a glow discharge in helium at atmospheric pressure" [J] also records that Wang Xinxin et al.'s team achieved area-wide decontamination improvement and promotion of DBD plasma discharge technology. This system can achieve DBD plasma decontamination of chemical warfare agents contained in a closed environment within a certain space. However, it still has significant limitations in the decontamination of outdoor chemical warfare agents. Therefore, this invention further improves upon this approach. Articles such as Decomposition of dimethylmethylphosphonate on Pt, Au, and Au-Pt clusters supposed on TiO2(110)[J] record that metal catalysts also have a certain catalytic decontamination effect on chemical warfare agents, but their service life is generally short and their use is also limited, such as the decontamination of chemical warfare agents is mostly achieved through contact catalytic oxidation.

[0014] Taking diethyl sulfide as an example, its molecular bonds are strong and difficult to degrade. Under the action of strong oxidizing agents such as hydroxyl radicals (OH-), the chemical bonds of diethyl sulfide break, cutting and degrading into small molecular compounds with non-toxic and harmless structures such as water and carbon dioxide.

[0015] In the reaction medium selected in this invention, titanium dioxide absorbs the energy of photoelectrons from the environment, exciting its own electrons from the valence band to the conduction band, leaving holes in the valence band to form photogenerated electron-hole pairs, thereby generating oxidation and enabling contact oxidation. This allows for a certain degree of decontamination of chemical warfare agents in gaseous environments. Furthermore, it generates superoxide anion radicals during this process, which can persist for approximately 6 seconds in gaseous environments and even longer in liquid environments, thus giving it broad application prospects for chemical warfare agent decontamination. However, unlike conventional adsorption treatments, chemical warfare agents typically cause titanium dioxide to gradually deactivate, resulting in a short lifespan. This invention further loads manganese oxide. Under DBD plasma-activated reaction medium conditions, some components of the manganese oxide can effectively cooperate with titanium dioxide. For example, some components assist in stimulating titanium dioxide to enhance its decontamination ability, while others can perform substitution oxidation, reducing oxygen loss in the titanium dioxide surface lattice and decreasing the occupation of strongly oxidizing holes, thereby extending its lifespan. Simultaneously, under DBD plasma excitation conditions, titanium dioxide can generate trace amounts of singlet oxygen compared to photoelectron excitation. Singlet oxygen also possesses a strong decontamination capability against chemical warfare agents. Furthermore, its long duration of existence (approximately 60-72 minutes) allows for deeper decontamination of complex environments. In some environments containing chemical warfare agents, certain components can generate hydroxyl radicals under the influence of the DBD plasma flow. Due to their extremely short duration, these radicals can almost immediately undergo contact decontamination. This is one of the limitations of DBD plasma decontamination technology. In the presence of certain special media, such as hydrogen peroxide, strong oxidizing decontamination components like atomic oxygen can be generated, also proving usability. However, the technical solution of this invention achieves direct annihilation through DBD plasma technology, while simultaneously generating superoxide anion radicals and singlet oxygen in the reaction medium under low-loss conditions for environmental decontamination. This multi-effect combination results in a more thorough and effective treatment of the environment.

[0016] Preferably, the manganese oxide in the reaction medium is manganese tetroxide and / or manganese dioxide, and contains at least 65 wt% manganese tetroxide.

[0017] Manganese tetroxide is a common defective manganese oxide. When combined with titanium dioxide in the technical solution of this invention, it can achieve non-occupied oxidation in the DBD plasma flow excitation environment and promote the generation of superoxide anion free radicals in titanium dioxide, thereby extending the service life of the reaction medium.

[0018] As a preferred option

[0019] The reaction medium contains at least 20 wt% manganese dioxide in manganese oxide.

[0020] Manganese dioxide possesses the characteristic of not being able to excite titanium dioxide, which can improve the excitation rate of titanium dioxide. At the same time, it also has the ability to catalytically oxidize and decontaminate environmental media.

[0021] As a preferred option

[0022] The chemical warfare agent medium is a liquid environment medium.

[0023] The method of this invention can be effectively used for the treatment of chemical warfare agents in liquid environments.

[0024] As a preferred option

[0025] The chemical warfare agent medium is contaminated drinking water.

[0026] Preferably, the DBD plasma generating device is one or more of a plasma probe, a plasma gun, and a surface discharge structure plasma sterilization module.

[0027] Preferably, the discharge liquid flow rate is 0.2–10 L / min, corresponding to per (1.2 × 1.2) m 2 At least one DBD plasma generating device should be installed in the effective area of ​​the reaction medium.

[0028] This invention's DBD plasma generator can circulate liquid environmental media and also excite reaction media. Excitation tests show that, taking point excitation of the DBD plasma probe as an example, a good chain excitation phenomenon can be observed within a radius of approximately 18 mm around the excitation point, producing a good decontamination effect. Therefore, to ensure effective use, it is necessary to ensure that every 1.54 m... 2 A DBD plasma generator can be set up to excite the effective area of ​​the reaction medium.

[0029] Secondly, this invention provides an application of a method for plasma degradation of chemical warfare agents.

[0030] The method is used for the degradation and removal of chemical warfare agents in liquid environmental media.

[0031] The method of this invention can be effectively used for the degradation and decontamination of chemical warfare agents in liquid environments.

[0032] As a preferred option

[0033] The reaction medium is a cylindrical DBD double quartz glass medium in a liquid environment.

[0034] To improve the effectiveness, the reaction medium is in plate and / or sheet form, which has a larger effective area and can effectively improve material utilization and washing efficiency.

[0035] The beneficial effects of this invention are:

[0036] (1) This invention achieves effective degradation and decontamination of chemical warfare agents by combining DBD plasma technology with metal oxide catalysts, which can more effectively and thoroughly remove the pollution caused by chemical warfare agents to the liquid environment and has a larger effective area; it has the advantages of high efficiency and thoroughness.

[0037] (2) The method of plasma degradation of chemical warfare agents in this invention is safe, has high degradation and decontamination efficiency, and produces no toxic byproducts. Detailed Implementation

[0038] The present invention will be further described below with reference to embodiments.

[0039] General Implementation Examples

[0040] A method for plasma degradation of chemical warfare agents,

[0041] A titanium dioxide carrier loaded with manganese oxide is placed in a chemical warfare agent medium as a reaction medium. A DBD plasma generator is set to point towards the reaction medium, and the distance between the emitter of the DBD plasma generator and the surface of the reaction medium is controlled to be 10-35 mm. The DBD plasma generator drives the plasma toward the reaction medium through an electric field. The chemical warfare agent in the chemical warfare agent medium is degraded by singlet oxygen and superoxide anions generated by the reaction medium, or by singlet oxygen, superoxide anions and hydroxyl radicals generated by the reaction medium and the chemical warfare agent medium.

[0042] Preferably, the manganese oxide in the reaction medium is manganese tetroxide and / or manganese dioxide, and contains at least 65 wt% manganese tetroxide.

[0043] As a preferred option

[0044] The reaction medium contains at least 20 wt% manganese dioxide in manganese oxide.

[0045] As a preferred option

[0046] The chemical warfare agent medium is a liquid environment medium.

[0047] As a preferred option

[0048] The chemical warfare agent medium is contaminated drinking water.

[0049] Preferably, the DBD plasma generating device is one or more of a plasma probe, a plasma gun, and a surface discharge structure plasma sterilization module.

[0050] Preferably, the discharge liquid flow rate is 0.2–10 L / min, corresponding to per (1.2 × 1.2) m2 At least one DBD plasma generating device should be installed in the effective area of ​​the reaction medium.

[0051] Application of a method for plasma degradation of chemical warfare agents

[0052] The method is used for the degradation and removal of chemical warfare agents in liquid environmental media.

[0053] As a preferred option

[0054] The reaction medium is a cylindrical DBD double quartz glass medium in a liquid environment.

[0055] The present invention will be further described clearly and in detail below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0056] Unless otherwise specified, all raw materials used in the embodiments of the present invention are commercially available or obtainable by those skilled in the art; unless otherwise specified, all methods used in the embodiments of the present invention are methods mastered by those skilled in the art.

[0057] Unless otherwise specified, the embodiments of this invention use a cylindrical DBD double quartz glass medium designed by the inventor as the reaction medium. The catalyst mesh uses a titanium mesh as a carrier, with a titanium dioxide nanoarray grown on its surface, and manganese dioxide and manganese tetroxide hydrothermally loaded, with a total loading of 0.5–0.6 g / cm³. 2 Among the manganese oxide loadings, manganese tetroxide had a loading rate of approximately 71%, and manganese dioxide had a loading rate of approximately 29%.

[0058] Example 1

[0059] A composite titanium-based catalytic mesh with a cutting radius of 18 mm was used as the reaction medium in an 8m... 3 A solvent pool (50L volume) is set up at the center of the sealed experimental chamber. The solvent pool is filled with an ethanol solution of diethyl sulfide (DES), a contaminated drinking water simulant (80mg DES: 1L anhydrous ethanol), and the flow rate is controlled at 5L / min. The reaction medium is placed at the bottom of the solvent pool and a commercially available 18kV AC DBD plasma reactor is set up at the center of the pool.

[0060] The plasma emission gun was activated, and the DES concentration was sampled and characterized every 0.5 minutes. The results showed that the concentration decreased to half (40 ± 0.5 mg / L) at approximately 6 minutes, and to below 0.5 mg / L at approximately 11.5 minutes. After 20 minutes, the reaction medium was safely removed, and the above experiment was repeated 9 times. During this process, the degradation half-life of the target substance (DES) remained at approximately 5–6 minutes, indicating that the reaction medium had good stability.

[0061] The above experiments demonstrate that the method of the present invention can be effectively used for the decontamination of chemical warfare agents in liquid environments.

Claims

1.A method for degrading chemical warfare agents by plasma, characterized in that, the method comprises: placing a titanium dioxide carrier loaded with manganese oxide into a chemical warfare agent medium as a reaction medium, setting a DBD plasma generating device to point to the reaction medium, and controlling the distance between the emitting end of the DBD plasma generating device and the surface of the reaction medium to be 10-35 mm, the DBD plasma generating device drives plasma to the reaction medium through a pulsed wave electric field, and the singlet oxygen, superoxide anion generated by the reaction medium, or the singlet oxygen, superoxide anion and hydroxyl radical generated by the reaction medium and the chemical warfare agent medium together, degrade the chemical warfare agent in the chemical warfare agent medium; wherein the manganese oxide is trimanganese tetraoxide and manganese dioxide, and contains at least 65 wt% trimanganese tetraoxide and at least 20 wt% manganese dioxide; the chemical warfare agent medium is a liquid environmental medium. 2.The method for degrading chemical warfare agents by plasma according to claim 1, characterized in that, the chemical warfare agent medium is contaminated drinking water. 3.The method for degrading chemical warfare agents by plasma according to claim 1, characterized in that, the DBD plasma generating device is a plasma probe. 4.The method for degrading chemical warfare agents by plasma according to claim 1, characterized in that, the DBD plasma generating device is a plasma gun. 5.The method for degrading chemical warfare agents by plasma according to claim 1, characterized in that, the DBD plasma generating device is a surface discharge structure plasma disinfection module. 6.The method for degrading chemical warfare agents by plasma according to claim 1, characterized in that, The flow rate of the discharge liquid is 0.2-10 L / min, corresponding to each (1.2*1.2) m 2 The effective area of the reaction medium is provided with at least one DBD plasma generating device. 7.The use of any one of the methods according to claims 1-6, characterized in that, the method is used for degrading and removing chemical warfare agents in a liquid environmental medium. 8.The use according to claim 7, characterized in that, the reaction medium is a cylindrical DBD double quartz glass medium in a liquid environmental medium.