A method for preparing plasma-activated water based on three-chamber coupling and intelligent regulation

Abstract

The application discloses a kind of preparation methods of plasma activated water based on three-chamber coupling and intelligent regulation and control.The method includes electrolytic unit, discharge unit, mixing unit and intelligent control unit, wherein the electrolytic unit includes cathode chamber and anode chamber, ion exchange membrane is arranged between the two, and corresponding anode effluent and cathode effluent are generated through cathode oxygen reduction path or anode water oxidation path;Discharge unit generates discharge effluent containing active nitrogen species by plasma discharge method.Through mixing and intelligent control unit, the mixing ratio and mixing order of discharge effluent, cathode effluent and anode effluent generated by different paths are intelligently controlled, so as to obtain plasma activated water with precisely customized physicochemical properties, to be suitable for sterilization and disinfection, agricultural application and use scenarios with higher environmental compatibility requirements.

Description

Technical Field

[0001] This invention belongs to the field of plasma-activated water preparation technology, specifically relating to a precise customization method for plasma-activated water based on a three-chamber heterogeneous coupling architecture and multi-path feedback regulation. Background Technology

[0002] Plasma-activated water (PAW) is rich in hydrogen peroxide (H2O2) and nitrite (NO2). - ), nitrate (NO3) - Reactive oxygen and nitrogen species, such as α, β, and γ, have broad application prospects in agricultural irrigation, disease control, disinfection and sterilization, and crop growth regulation. By regulating the types, proportions, and reaction pathways of active species in activated water, they can exhibit differentiated functional characteristics in different application scenarios.

[0003] Existing methods for preparing PAW (Potentially Oriented Wastewater) mainly include dielectric barrier discharge (DBD), gas-liquid discharge, needle-water discharge, sliding arc, jet discharge, and electrolysis. However, most of these methods employ a single-chamber or dual-chamber structure, where reactive oxygen species (ROS) and reactive nitrogen species (RNS) are simultaneously generated in the same reaction system. This results in their coupling during the generation stage, making independent control difficult according to specific needs. For example, the generation of H2O2 is highly sensitive to current, voltage, and solution pH, while NO2... - The formation of [something] is mainly affected by the composition of the discharge gas, the nitrogen content, and the acidity of the solution, and these factors often cannot be optimized separately in a single reaction system.

[0004] In practical applications such as agriculture, PAW typically treats raw water such as tap water, well water, or surface water, which have relatively complex compositions. When plasma or electrolysis directly acts on the same water body, the local strong electric field, high-energy particles, and rapid acidification process can easily trigger multiple parallel reactions, making the bioactive species generation pathway more complex and further exacerbating the coupling relationship between ROS and RNS, thereby reducing the controllability and reproducibility of the active components.

[0005] Furthermore, existing electrolytic methods for preparing H2O2 typically operate in acidic or alkaline conditions, whereas methods such as DBD (detonation-induced detonation) are used to prepare NO2. - At the same time, the solution pH often drops rapidly, and these characteristics are not conducive to directly obtaining activated water suitable for agricultural applications or scenarios with high environmental compatibility requirements. Different crops and application scenarios have significantly different requirements for solution pH, ROS / RNS ratio, and reaction intensity, making it difficult for existing PAW technology to simultaneously achieve controllable bioactive species generation pathways and adjustable final solution properties.

[0006] The aforementioned technical deficiencies limit the promotion and application of plasma-activated water in precision agriculture and various other applications. Therefore, there is an urgent need to develop a plasma-activated water preparation method that uses raw water as the treatment target, couples multiple reaction units, and achieves programmable control of active species and pH. Summary of the Invention

[0007] In view of this, the purpose of this invention is to overcome the shortcomings of traditional PAW preparation, such as uncontrollable coupling of reactive oxygen species (ROS) and reactive nitrogen species (RNS) during the generation stage, strong binding between solution pH and species concentration, and limited energy efficiency. This invention provides a plasma-activated water preparation method based on three-compartment coupling and intelligent control, aiming to achieve independent optimization of product parameters in different units, spatial decoupling of the active species generation pathway, and programmable customization of the final solution properties. To achieve the above objectives, this invention provides the following technical solution: A method for preparing plasma-activated water based on three-chamber coupling and intelligent control includes the following steps: Step 1: The raw water (such as tap water or well water) is pretreated by sequentially passing through 1–50 μm mechanical filtration, 0.22–1 μm precision filtration, and activated carbon adsorption. The pretreatment unit is equipped with differential pressure monitoring and bypass structure to protect the subsequent ion exchange membrane from particulate matter or residual chlorine contamination.

[0008] Step 2: Separation and preparation of heterogeneous active components ROS source preparation via electrolysis unit: The electrolysis unit includes a cathode chamber and an anode chamber separated by an ion exchange membrane. Depending on the application requirements, select one of the following kinetic paths: Cathode oxygen reduction pathway A (cathode 2e) - ORR): An alkaline product containing H2O2 is prepared directionally in the cathode chamber via a two-electron oxygen reduction reaction, while H2O2 is generated in the anode chamber for pH adjustment. + .

[0009] Anodic water oxidation pathway B (anodic 2e) - WOR: An acidic product containing H2O2 is prepared directionally in the anode chamber using a special electrode via a two-electron water oxidation reaction, while OH- is generated in the cathode chamber. - Adjusting fluid.

[0010] The RNS source is prepared by a discharge unit: plasma discharge (preferably dielectric barrier discharge gas-liquid bubbling) is used to generate NO2-rich gas at a discharge voltage of 5–50 kV and a gas flow rate of 1–10 L / min. - With NO3 - The discharge product.

[0011] Step 3: Intelligent Blending and pH Customization The intelligent control unit performs closed-loop control of the mixing ratio (α, β, γ) of the cathode product, anolyte product, and discharge product based on the target pH and the proportion of active species. By adjusting the mixing flow rate, the pH of the final PAW is precisely stabilized within a preset range, including strongly acidic (pH < 3.3), growth-promoting (pH 5.0–5.5), or neutral environment compatible (pH 6.5–7.5).

[0012] Mixing sequence control: The control unit can dynamically set the mixing sequence (such as mixing the cathode liquid and the discharge product liquid first, and then adding the anolyte) to achieve in-situ induction of the strong oxidizing intermediate peroxynitrite (ONOOH).

[0013] The beneficial effects of this invention are as follows: This system achieves physical spatial decoupling and independent concentration control of active component generation, overcoming the problems of physical contact, chemical coupling, and immediate deactivation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) during the generation stage in traditional single-chamber or dual-chamber systems. By physically separating the electrolytic ROS generation unit and the DBD RNS generation unit, independent optimization of generation parameters for different active species is achieved, significantly improving the efficiency of H2O2 and NO2 generation. - The steady-state accumulation concentration.

[0014] This breakthrough breaks the deadlock of strong coupling between the physicochemical properties of the solution and the concentration of active species: by constructing three independent product sources—acid, alkali, and active components—it completely solves the drawback of rapid pH acidification during discharge in traditional PAW preparation, which cannot be independently adjusted. Utilizing an intelligent mixing unit for precise closed-loop control of the output ratio, it achieves customized adjustment of the final product pH (e.g., strongly acidic, weakly acidic growth-promoting, and neutral environmentally friendly) while maintaining specific active species concentrations.

[0015] Path A (cathode 2e) - The ORR pathway achieves a logical closed loop and high-efficiency output at the ion level: the cathode chamber utilizes the two-electron oxygen reduction reaction (2e... - ORR) efficiently and directionally prepares H2O2 product while generating OH- - Driven by an electric field, it participates in anodic oxidation across the membrane, thereby generating H₂ on the anode side for pH adjustment. + This design not only achieves charge balance, but also enables ROS generation and H₂O production. + The resulting closed-loop logic allows for an energy efficiency of up to 800 μmol / kWh for the electrolytic production of H2O2.

[0016] Path B (Anode 2e) -The WOR pathway achieves acidic steady-state storage and pathway innovation for reactive oxygen species: Pathway B is not a simple spatial partitioning, but rather employs "anodic two-electron water oxidation (2e... - A heterogeneous coupling architecture of "WOR + DBD gas-liquid discharge" is used. The anode generates a large amount of H₂O₂ during the preparation of H₂O₂. + This ensures that hydrogen peroxide is in its most stable acidic storage environment from the moment it is generated, effectively preventing disproportionation decomposition under alkaline conditions. Combined with the application of a bipolar membrane (BPM), it completely solves the energy loss caused by acid-base neutralization.

[0017] In-situ induced formation and dynamic lifetime management of the highly oxidizing intermediate (ONOOH) were achieved: Through a smart control unit, the mixing ratio and sequence of multiple product solutions were dynamically switched, enabling the controlled in-situ generation of the highly active intermediate ONOOH. This provides core methodological support for constructing customized functional water systems that meet the needs of different biological applications.

[0018] The system improves the controllability and applicability of treating complex raw water: the independent operation of the pretreatment unit and the heterogeneous unit avoids multi-path parallel side reactions caused by complex raw water components such as tap water or well water under strong discharge / electrolysis environments. The intelligent closed-loop system based on sensor feedback improves the repeatability of active species generation and constructs a "programmable" preparation system suitable for multiple application scenarios.

[0019] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This invention is based on electrolytic dual-chamber 2e - The design diagram of the three-chamber coupled system for the ORR path (cathode oxygen reduction path A) is shown. The electrolysis unit employs a two-electron oxygen reduction path at the cathode. The cathode chamber generates a cathode product containing hydrogen peroxide and hydroxide ions, while the anode chamber generates an anolyte containing hydrogen ions. The discharge unit (using a dielectric barrier discharge unit as an example) operates in an independent parallel mode with the electrolysis unit; that is, the outlet of the pretreatment unit is independently connected to the inlet of both the electrolysis unit and the discharge unit via pipelines.

[0021] Figure 2 This invention is based on electrolytic dual-chamber 2e- Design diagram of a three-chamber coupled plasma-electrolysis composite system (anodic water oxidation path B) using the WOR path. The electrolysis unit employs a two-electron anodic water oxidation path. The anode chamber directionally generates an acidic anolyte containing hydrogen peroxide and hydrogen ions, while the cathode chamber correspondingly generates a cathodic solution containing hydroxide ions. The discharge unit (using a dielectric barrier discharge unit as an example) operates in an independent parallel mode with the electrolysis unit; that is, the outlet of the pretreatment unit is independently connected to the inlet of both the electrolysis unit and the discharge unit via pipelines.

[0022] Figure 3 This invention is based on electrolytic dual-chamber 2e - Design diagram of a three-chamber coupled plasma-electrolysis composite system for the ORR path (cathode oxygen reduction path A). The electrolysis unit employs a two-electron oxygen reduction path at the cathode. The cathode chamber generates a cathode product containing hydrogen peroxide and hydroxide ions, while the anode chamber generates a corresponding anolyte containing hydrogen ions. This diagram illustrates the system's series enhancement mode, where the outlet of the pretreatment unit is connected to the inlet of the electrolysis unit. The outlet of the electrolysis unit's cathode chamber is connected via a pipeline to the inlet of the discharge unit (using a dielectric barrier discharge unit as an example). The alkaline cathode product is used as the solution to be treated to enhance the stability of nitrite ions.

[0023] Figure 4 This invention is based on electrolytic dual-chamber 2e - Design diagram of a three-chamber coupled plasma-electrolysis composite system for the WOR path (anodic water oxidation path B). The electrolysis unit employs a two-electron anodic water oxidation path. This diagram illustrates the system's series enhancement mode, where the outlet of the pretreatment unit is connected to the inlet of the electrolysis unit. The outlet of the cathode chamber of the electrolysis unit is connected via a pipeline to the inlet of the discharge unit (using a dielectric barrier discharge unit as an example), introducing the generated strongly alkaline conditioning solution as the solution to be treated to prepare high-concentration nitrite.

[0024] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Detailed Implementation

[0025] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] System composition and connection method Regarding the system composition and connection method, the present invention provides a plasma-activated water preparation system based on three-chamber coupling and intelligent control, comprising a pretreatment unit, an electrolysis unit, a discharge unit, a mixing unit, and an intelligent control unit. The discharge unit described in this invention (i.e., the dielectric barrier discharge unit in the accompanying drawings) is designed to generate nitrogen-containing active species. Although the accompanying drawings use a dielectric barrier discharge (DBD) structure as an example, those skilled in the art should understand that, depending on different application requirements, the discharge unit can be replaced with any plasma generator capable of gas-liquid discharge, such as a plasma jet device, a sliding arc discharge device, a corona discharge device, or an arc discharge device. The electrolysis unit consists of a cathode chamber, an anode chamber, and an ion exchange membrane between them. After pretreatment, the raw water enters the electrolysis unit and the discharge unit separately or according to a program. The resulting cathode product, discharge product, and anode product are mixed proportionally or sequentially in the mixing unit according to control logic to obtain plasma-activated water with the target pH and target active component ratio.

[0027] Preprocessing unit The raw water can be tap water, well water, surface water, or a combination thereof. To prevent long-term operation from causing fouling, scaling, or clogging of the ion exchange membrane (such as Nafion 212, FAA-3-PK-130, etc.) due to suspended particles, colloids, humic substances, and residual chlorine, this invention includes a pretreatment unit before the water enters the electrolysis unit. The pretreatment unit includes one or more of the following steps: (1) 1–50 μm mechanical filtration, used to remove large particles such as sand and algae debris; (2) 0.22–1 μm precision filtration (microfiltration / ultrafiltration) to reduce turbidity and colloidal load; (3) Activated carbon adsorption is used to remove organic matter and residual chlorine; (4) If necessary, softening treatment (such as ion exchange softening or scale inhibitor) should be performed to reduce Ca². + / Mg² + The risk of scaling.

[0028] Preferably, the pretreatment unit is equipped with a differential pressure monitoring and bypass / backwashing structure: when the filtration differential pressure exceeds the threshold, it automatically switches or cleans to ensure long-term stable operation of the membrane module.

[0029] Plasma discharge unit (RNS generation) The discharge unit is configured as a plasma generator to produce nitrogen-containing active species, specifically including any one of a dielectric barrier discharge unit, a plasma jet unit, a sliding arc discharge unit, or a corona discharge unit. In a preferred embodiment of the present invention, a dielectric barrier discharge (DBD) bubbling reactor is used as an example for illustration, and its typical operating parameters are as follows: Discharge voltage: 5–50 kV (preferably 16–24 kV); Gas flow rate: 1–10 L / min (typical parameter is 4 L / min); Discharge time: 10–60 min for continuous flow operation or single treatment; Working gas: air, N2 / O2 mixture, or a mixture of gases with CO2 added if necessary; Product: NO2 - NO3 - This can be accompanied by changes in solution acidity and an increase in oxidation-reduction potential (ORP).

[0030] The DBD unit and the electrolysis unit are physically separated and their parameters are set independently, allowing H2O2 and NO2 to react. - The generation processes are independent of each other and can be optimized separately.

[0031] Mixing unit and intelligent control unit The mixing unit includes a metering pump, solenoid valves, and a mixer, and is connected to an intelligent control unit. The control unit controls the flow rate and mixing order of the three output solutions (cathode product, discharge product, and anolyte product) based on a preset target output formula. An example control strategy is as follows: A target pH and reaction intensity are set; the controller calculates the mixing coefficients α, β, and γ based on real-time measured parameters such as pH and ORP, and outputs: V final = αV cathode + βV DBD + γV anode The control unit is implemented using a Programmable Logic Controller (PLC) or a microcontroller. The programmable applications for different pH ranges are described below.

[0032] V final The total flow rate or total volume of plasma-activated water (PAW) obtained at the end.

[0033] V cathode The flow rate or volume of the cathode product output from the cathode chamber of the electrolysis unit; in path A, it is rich in H2O2 and OH-. - Under path B, it mainly consists of OH. - Adjusting fluid.

[0034] V DBD The flow rate or volume of the discharge product output from the dielectric barrier discharge (DBD) unit, rich in NO2. - and NO3 - V anode The flow rate or volume of the anolyte output from the anode chamber of the electrolysis unit; in path A, it is mainly H. + The conditioning solution, in path B, is rich in H2O2 and H2O. + .

[0035] α: Mixing coefficient of cathode product solution, representing the volume ratio or flow weight of cathode product solution in the final product solution, which is dynamically and closed-loop adjusted by the intelligent control unit according to the preset target pH value and the ratio of active components.

[0036] β: Mixing coefficient of the discharge product, representing the volume ratio or flow weight of the discharge product in the final product.

[0037] γ: Mixing coefficient of anolyte, representing the volume ratio or flow weight of anolyte in the final product.

[0038] By controlling the proportion and sequence of the mixing units, this invention can obtain activated water with different pH ranges and different active species characteristics, as shown in the following examples: (1) pH<3.3: Activated water with higher reaction intensity can be obtained, which is suitable for application scenarios with high reaction intensity requirements (such as disinfection and sterilization). (2) pH 5.0–5.5: can obtain activated water that is more suitable for the accumulation / utilization of certain reactive nitrogen and oxygen intermediates, and is suitable for agricultural applications such as preservation and growth promotion; (3) pH ≈ 7: Neutral activated water with better environmental compatibility can be obtained and can be used for irrigation water, etc. At the same time, published literature shows that neutral systems have good effects in some biological applications. This invention can provide a means of preparing activated water in this pH range.

[0039] Example 1 (Custom-activated water with pH 5.0–5.5) The above mixing process uses an intelligent control unit to control the flow rate formula V. final = αV cathode + βV DBD + γV anodeThe mixing coefficients in the system were dynamically adjusted in a closed loop. As shown in Table 1, the experimental results verified the "programmable" customization capability of the system for physicochemical parameters: while ensuring that the core active components such as nitrite (480 μmol / L) and hydrogen peroxide (850 μmol / L) were at high concentrations, the pH of the final product was successfully locked from 7.2 in the raw water to 5.3, perfectly matching the optimal slightly acidic range for plant growth. Based on the two-electron oxygen reduction pathway A at the cathode, the electrolysis unit used a cation exchange membrane (CEM), specifically a Nafion 212 perfluorosulfonic acid proton exchange membrane manufactured by DuPont. Pretreated water was introduced into the cathode chamber, and oxygen was introduced to increase the dissolved oxygen concentration. Under DC power supply conditions, with a voltage of 10 V and a current of 100 mA, electrolysis was performed for 10 min to obtain an alkaline cathode product with an H2O2 concentration of 380 μM. Hydroxide ions generated at the cathode migrate across the membrane to the anode side, producing an acidic anolyte in situ with a stable pH of 2.5–3.0. The DBD unit generates NO2 at 20 kV. - A discharge product solution with a concentration of 550 μM was prepared. The mixing ratio was set at cathode product solution: discharge product solution: anode product solution = 5:4:1, and the pH of the final mixture stabilized at 5.2. Actual measurements showed that this activated water increased the germination potential of mung bean seeds by approximately 15%.

[0040] Table 1: Agricultural Promoting Models - Path A

[0041] Example 2 (High-reactivity activated water with pH < 3.3) The above mixing process uses a mixing unit to logically switch the liquid addition sequence. By prioritizing the mixing of cathode product and discharge product, the preparation steps of Example 1 are repeated, and the mixing flow ratio is set as cathode product: discharge product: anode product = 1:2:7.

[0042] During the mixing stage, the proportion of anolyte was increased or the order of addition was changed to ensure a final pH < 3.3, thus obtaining activated water suitable for disinfection and sterilization applications. As shown in Table 2, the H2O2 generated by electrolysis and the NO2 generated by plasma were successfully induced. - An acid-catalyzed reaction occurs, generating highly reactive intermediate nitrous peroxide (ONOOH) in situ. Benefiting from the strong oxidizing properties of ONOOH, the redox potential (ORP) of the solution jumps to 495 mV. After 5 minutes of treatment with *E. coli*, the expected kill rate is over 99.99% (>4-log). 10 Inactivation).

[0043] Table 2. Disinfection and sterilization modes - Path A

[0044] Example 3 (neutral activated water with pH ≈ 7) Repeat the preparation steps of Example 1, and in the mixing stage, make the cathode product and discharge product the main components and the anode product the auxiliary component, so that the final pH is close to 7, in order to obtain neutral activated water with higher environmental compatibility.

[0045] Set the mixing flow ratio to cathode product: discharge product = 1:1 (close the anolyte branch or the anolyte percentage is <2%).

[0046] Activated water with a pH of approximately 7.0 is obtained by neutralizing the acidity of the discharge product solution with the weak alkalinity of the catholyte. This method provides a balanced concentration of active species and is suitable for disinfecting acid-sensitive environmental surfaces. Example 3 verifies the system's ability to prepare environmentally compatible activated water through the self-neutralization of the product solution. By setting the mixing ratio of the catholyte and discharge product solution to approximately 1:1 using the intelligent control unit, the weak alkaline catholyte generated by electrolysis effectively counteracts the spontaneous acidification of the discharge product solution. The final product solution pH is stabilized at around 7.0 without the need for external chemical regulators. This mode maintains a high concentration of active components while significantly reducing irritation to the environment and biological surfaces. Example 4 (Custom-activated water with pH 5.0–5.5) Based on the two-electron water oxidation pathway at the anolyte (pathway B), the electrolysis unit employs a bipolar membrane (BPM), specifically the Fumasep FBM type bipolar membrane manufactured by Fumatec BWT GmbH, Germany. The anode uses a high oxygen evolution overpotential electrode (Boron-Doped Diamond, BDD), specifically a Diachem series boron-doped diamond electrode manufactured by Condias GmbH, Germany, with niobium (Nb) as the substrate material. Electrolysis is performed at 12 V and 150 mA for 15 min, directly generating an acidic H₂O₂ product solution with a concentration of 400 μM (pH = 3.0) at the anode. The bipolar membrane supplements the cathode side with hydroxide ions to provide an alkaline conditioning solution. The mixing ratio is cathode product solution: anode product solution: discharge product solution = 5:1:4, achieving customized output. Example 4 demonstrates the advantages of acidic steady-state storage of reactive oxygen species under path B. The oxidation of water with two electrons at the anode (2e-WOR) produces a large amount of H₂O₂ along with the reaction. +This process ensures that hydrogen peroxide is in its most stable acidic storage environment from the moment of its formation, effectively preventing disproportionation and decomposition under alkaline conditions. As shown in Table 3, its 24-hour species retention rate is as high as 98.2%, far exceeding that of traditional preparation methods.

[0047] Table 3: High-stability storage mode - Path B

[0048] Example 5 (High-reactivity activated water with pH < 3.3) Repeat the steps of Example 4, setting the mixing ratio to cathode product: anode product: discharge product = 1:7:2. By increasing the proportion of acidic anode product, strong oxide species accumulation is achieved under extremely low pH conditions.

[0049] Example 6 (neutral activated water with pH ≈ 7) Repeat the steps of Example 4, setting the mixing ratio to cathode product: anode product: discharge product = 7:1:2. Using a strongly alkaline cathode, as shown in Table 4, through precise ratio control of the mixing unit, the high-concentration strongly alkaline cathode solution generated by electrolysis is used to neutralize the acidic discharge product and anode acidic product generated by the dielectric barrier discharge unit in a closed-loop logic. Experimental data shows that the pH value of the final product is precisely stabilized at 7.0 from the original water's 7.1, achieving true neutral equilibrium. While maintaining the residual effective oxidizing power (38 mg / L) and the concentration of active components, the conductivity of the finished solution meets emission standards and exhibits extremely low environmental irritation, making it suitable for landscape water restoration and disinfection of sensitive surfaces susceptible to acid and alkali corrosion.

[0050] Table 4: Environmentally Compatible Neutral Model - Path B

[0051] Example 7 This invention completely solves the problem of instantaneous species inactivation in traditional single reaction systems by physically decoupling the reactive oxygen species (ROS) preparation unit from the reactive nitrogen species (RNS) preparation unit.

[0052] Table 5: Comparison of Physical Decoupling and Synergistic Enhancement of Active Components

[0053] As shown in Table 5, the H2O2 concentration prepared by this invention (820 μmol / L) is significantly higher than that of single DBD treatment (75 μmol / L), demonstrating that the decoupled architecture effectively avoids the electric field degradation of hydrogen peroxide during the discharge process. Thanks to the strong oxidizing intermediate induced within the mixing unit, the final product's redox potential (ORP) reaches 495 mV, achieving a 99.9999% kill rate against E. coli (6-log inactivation), representing a 3 to 5 order of magnitude improvement in disinfection efficiency compared to single treatment methods. Example 8 This invention utilizes the characteristics of path B (anodic water oxidation path) to ensure that H2O2 is in the acidic storage environment generated in situ in the anode chamber at the moment of preparation.

[0054] Table 6: Comparison of Long-Term Stability (Residual Active Ingredient Lifetime) of Activated Product Solution

[0055] As shown in Table 6, during a 30-day long-term storage experiment, the residual oxidizing power of the product from pathway B of this invention only slowly decreased from 465 mg / L to 425 mg / L, demonstrating extremely high stability. In contrast, the traditional single-compartment DBD activation solution, lacking an acidic steady-state storage mechanism, experienced a precipitous drop in its effective active ingredient after 7 days, and by 30 days, its effective oxidizing power was undetectable. This result demonstrates the significant technological advantage of this invention in the commercial application of activated water and in long-distance transportation scenarios.

[0056] Example 9 (Pathway A Enhancement Mode: Alkaline Environment Stabilizes Nitrite) This embodiment uses the cathode oxygen reduction path A of Embodiment 1. The difference from Embodiment 1 is that the "series enhancement mode" of the pipeline switching mechanism is activated, such as... Figure 3 As shown, the alkaline cathode product from the electrolysis unit is directly introduced into the dielectric barrier discharge (DBD) unit as the discharge matrix liquid.

[0057] Pretreated water is introduced into the cathode chamber of the electrolysis unit, which operates under conditions of 12 V voltage and 2 A current. The cathode passes through 2e... - The ORR reaction produces a product containing H2O2 and OH-. - The cathode product solution (pH ≈ 11.5) was used. Instead of introducing fresh raw water, the cathode product solution was directly introduced into the DBD unit. Gas-liquid bubbling discharge was performed for 15 min at a discharge voltage of 20 kV and an air flow rate of 4 L / min. The discharged liquid (rich in H2O2 and NO2) was then... - and OH - ) and the acidic conditioning solution (containing H2) generated in the anode chamber of the electrolysis unit+ Mix in the mixing unit.

[0058] In an alkaline catholy solution environment, a high pH effectively inhibits the disproportionation reaction of nitrite: 3NO2 - + 2H + → 2NO +NO3 - + H2O, compared to directly using raw water for discharge (Example 1), the NO2 produced in the discharge solution in this example - The concentration increased from 550 μmol / L to 1280 μmol / L, an increase of over 130%. Since H₂O₂ was pre-present in the discharge solution, although some decomposed, it remained at approximately 300 μmol / L. When the final injection of acidic anolyte adjusted the pH to 3.2, the high concentration of NO₂... - A large amount of ONOOH is generated instantaneously. The kill log of Bacillus subtilis is increased from 3.5 log to 5.8 log.

[0059] Example 10 (Pathway B Enhancement Mode: Preparation of High-Purity Active Nitrogen) This embodiment uses the anodic water oxidation path B of Embodiment 4. The difference from Embodiment 4 is that the "series enhancement mode" of the pipeline switching mechanism is activated. Figure 4 As shown, the alkaline cathode product from the electrolysis unit is directly introduced into the dielectric barrier discharge (DBD) unit as the discharge matrix liquid.

[0060] Pretreated water was introduced into the cathode chamber of the electrolysis unit and electrolyzed for 15 minutes at 12 V and 150 mA. The cathode chamber produced a product containing only OH-. - The strongly alkaline cathode product solution (pH ≈ 12.0) contains no H2O2 (to avoid consumption during discharge) and is in a strongly alkaline environment, so the NOx generated during discharge is efficiently absorbed and converted into NO2. - Instead of introducing fresh raw water, the above-mentioned cathode product solution is directly passed into the DBD unit. The NO2 in the DBD product solution... - The concentration reached 1550 μM, the highest among all examples.

[0061] High concentration of NO2 at the DBD unit outlet - The alkaline discharge product and the acidic anolyte (580 μM H2O2) from the anode chamber are combined in the mixing unit. The two high-concentration liquids (strongly acidic H2O2 and strongly alkaline NO2) are then mixed. - After the solutions are combined in the mixing unit, the pH is neutralized to approximately 3.0, inducing a strong synergistic reaction. In rapid cold sterilization experiments on medical devices, complete inactivation of Staphylococcus aureus (>6 log) can be achieved in just 30 seconds.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing plasma-activated water based on three-chamber coupling and intelligent control, characterized in that, The steps include: (1) introducing the first pretreated water into an independent electrolysis unit, which includes a cathode chamber and an anode chamber, with an ion exchange membrane between the cathode chamber and the anode chamber to suppress direct mixing of the reaction environments in the two chambers; the electrolysis unit can select any of the following electrode reaction paths: Cathode oxygen reduction path A: The electrode surface in the cathode chamber generates a cathode product containing hydrogen peroxide and hydroxide ions through a two-electron oxygen reduction reaction, and the corresponding anode chamber generates an anode product containing hydrogen ions. Alternatively, anodic water oxidation path B: the electrode surface in the anode chamber generates an anodic product containing hydrogen peroxide and hydrogen ions through a two-electron water oxidation reaction, and the corresponding cathode chamber generates a cathode product containing hydroxide ions. (2) The liquid to be treated is introduced into an independent discharge unit, which is a plasma discharge unit; the liquid to be treated is the second pretreated water or the cathode product generated in step (1); a discharge product containing active nitrogen species is generated by plasma discharge; wherein, when the cathode product is introduced as the liquid to be treated, the hydroxide ions therein are used to inhibit the disproportionation decomposition of nitrite. (3) The discharge product, cathode product and anode product are introduced into the mixing unit. Under the control of the intelligent control unit, the mixing ratio and mixing order of each product are adjusted to obtain plasma activated water with different properties.

2. The method for preparing plasma-activated water according to claim 1, characterized in that: In path A of step (1), the hydroxide ions generated at the cathode are driven by the electric field to migrate across the ion exchange membrane to the anode chamber and generate hydrogen ions in situ; oxygen-containing gas is added to the cathode chamber to promote the oxygen reduction reaction. In path B of step (1), the ion exchange membrane is a bipolar membrane, which utilizes its water dissociation characteristics to replenish hydrogen ions to the anode side and hydroxide ions to the cathode side.

3. The method for preparing plasma-activated water according to claim 1, characterized in that: In step (2), the plasma discharge unit is preferably a dielectric barrier discharge unit; the plasma of the discharge unit contacts the liquid to be treated in step (2) in either direct contact or gas-liquid bubbling contact.

4. The method for preparing plasma-activated water according to claim 1, characterized in that: The pretreatment water steps include one or more combinations of 1–50 μm mechanical filtration, 0.22–1 μm precision filtration, and activated carbon adsorption treatment.

5. The method for preparing plasma-activated water according to claim 1, characterized in that, The operating parameters of the electrolysis unit in step (1) include: voltage of 1–100 V and current of 0.1–20 A.

6. The method for preparing plasma-activated water according to claim 1, characterized in that, The operating parameters of the discharge unit in step (2) include: discharge voltage 5–50 kV, gas flow rate 1–10 L / min. The working gas of the dielectric barrier discharge unit is one or more of air, oxygen, nitrogen, and their mixtures.

7. The method for preparing plasma-activated water according to claim 1, characterized in that: In step (3), the intelligent control unit stores preset pH values ​​and active species ratio parameters corresponding to different application scenarios. The intelligent control unit automatically matches the target parameters and adjusts the mixing ratio according to the scenario selected by the user, so as to realize the large-scale continuous adjustment of the physicochemical properties of plasma-activated water.

8. The method for preparing plasma-activated water according to claim 1, characterized in that, In step (3), the mixing ratio and mixing order are set by the intelligent control unit, and finally the strong oxidizing intermediate peroxynitrite is generated in situ under controlled conditions.

9. A plasma-activated water preparation system for implementing the method of any one of claims 1-8, characterized in that, include: The system comprises a pretreatment unit, an electrolysis unit, a discharge unit, a mixing unit, and an intelligent control unit; characterized in that the system further includes a pipeline switching mechanism for selectively introducing pretreated raw water or cathode product from the cathode chamber of the electrolysis unit into the inlet of the discharge unit as a reaction liquid source; the cathode product outlet, anode product outlet of the electrolysis unit, and discharge product outlet of the discharge unit are respectively connected to the mixing unit through independent delivery pipelines, and each pipeline is equipped with a flow regulating device controlled by the intelligent control unit.

10. The plasma-activated water preparation system according to claim 9, characterized in that, The mixing unit includes a mixing container and a pH sensor and a redox potential sensor located at its outlet, forming a closed-loop feedback control circuit with the intelligent control unit.

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