Method and device for generating high-concentration nitrogen nanobubbles based on multi-mechanism cooperation

Abstract

The invention relates to the technical field of nanotechnology, and discloses a high-concentration nitrogen nanobubble generation method based on multi-mechanism synergy, which comprises the following steps of: simultaneously applying a multi-stage vortex for generating turbulent flow and shearing force and periodically pressurizing and depressurizing the inside of a cavity to a water sample of supersaturated dissolved nitrogen flowing into the cavity, and in the process of reducing the pressure in the cavity, a pulse electric field which is synchronous with the frequency and the phase of the periodic pressure increasing and reducing is applied, and coalescence between interfaces of the continuously generated initial nanobubbles is inhibited through the pulse electric field. A pressure oscillation cavity of the device is provided with a water sample input port and a target concentration nitrogen nanobubble water sample output port, a multi-stage eddy current system for generating turbulent flow is fixedly arranged in the cavity, a pressure adjusting system capable of forming periodic pressure oscillation is communicated with the outside of the cavity, and an electric field generating system containing a relative electrode and a pulse power supply is arranged in the cavity. And the self-adaptive control unit monitors the pressure oscillation frequency and phase in real time and controls the pulse power supply to output a synchronous pulse electric field in a voltage reduction stage.

Description

Technical Field

[0001] This invention relates to the field of nanotechnology, and specifically to a method and apparatus for generating high-concentration nitrogen nanobubbles based on a multi-mechanism synergy. Background Technology

[0002] Nanobubbles, typically referring to gas microbubbles with a diameter of less than 200 nanometers, exhibit enormous application potential in water treatment, agriculture, and biomedicine due to their extremely high specific surface area, excellent stability in liquids, and high gas mass transfer efficiency. Currently, existing technologies for generating nanobubbles mainly include the following types: 1. Ultrasonic Cavitation Method: This method induces localized negative pressure in a liquid using high-intensity sound waves. When the negative pressure falls below the liquid's vaporization pressure, cavitation occurs, forming micro- and nano-sized bubbles. Studies have shown that this method can generate nitrogen nanobubbles with a concentration of approximately 10⁹ bubbles / mL, with diameters between 100 and 120 nanometers, and their stability can last for several months. However, the physical limitations of this method lie in its low energy utilization efficiency; most of the ultrasonic energy is dissipated as heat, resulting in high overall energy consumption. Furthermore, high-power ultrasonic equipment is complex and expensive, making large-scale, low-cost industrial production difficult.

[0003] 2. Fluid Dynamics Cavitation Method: This method utilizes the local pressure fluctuations caused by changes in fluid velocity as it flows through a Venturi tube, orifice plate, or rotating device to induce cavitation, thereby generating nanobubbles. Literature reports that by optimizing the structure of the eddy current generator, bulk nanobubbles with diameters less than 200 nm can be generated, but their concentration typically remains at around 10⁹ bubbles / mL. Its limitations lie in the fact that relying solely on fluid dynamics, the nucleation efficiency and final concentration of bubbles are constrained by the fluid energy conversion efficiency and flow field uniformity, making it difficult to achieve significant breakthroughs in concentration. Furthermore, there is a lack of effective means to control the stability of newly formed bubbles.

[0004] 3. Periodic Pressure Variation Method: This method involves periodically applying and releasing pressure to a liquid containing saturated dissolved gases. The pressure changes alter the gas's solubility, inducing the gas to precipitate from a supersaturated state and form bubble nuclei. Studies show that this method can increase the concentration of nitrogen nanobubbles to 1.9 × 10¹³ cells / mL. However, the core problem with this method is that while it can induce a large number of bubble nucleations, it lacks a stabilization mechanism for the initial nucleated bubbles. Newly formed bubbles are prone to coalescence and Ostwald ripening—a process where small bubbles dissolve and large bubbles grow—ultimately resulting in a wide bubble size distribution (e.g., a bimodal distribution of 68 nm and 397 nm) and poor long-term stability (e.g., stability only lasts for more than 48 hours).

[0005] 4. External Electric Field Method: This method induces bubble nucleation and enhances its stability by applying an external electric field to the liquid. Studies have found that the electric field can enhance gas solubility and stabilize the bubble interface through effects such as dielectrophoresis and surface polarization, especially suitable for hydrophobic gases such as nitrogen, achieving concentrations of 10¹³-10¹⁴ bubbles / mL and stability lasting for months. However, existing techniques typically employ static DC electric fields or simple on / off electric fields. This method lacks precise timing matching with the dynamic process of bubble nucleation, resulting in low energy utilization efficiency and limited improvement in bubble stability. Furthermore, this method itself does not address the problem of efficiently generating a large number of initial bubble nuclei.

[0006] 5. Electrolysis: This method directly generates hydrogen and oxygen nanobubbles on the electrode surface through an electrochemical reaction, with concentrations reaching up to 10¹⁵ nanobubbles / mL. However, this method is not suitable for preparing gases such as nitrogen that are not produced by electrolysis, and the electrolysis process itself poses certain safety hazards.

[0007] In summary, the existing technology or method has one or more of the following technical defects: (1) Insufficient concentration: The concentration of nanobubbles generated by traditional methods is generally between 10⁹ and 10¹³ per mL, which is difficult to meet the requirements of industrial applications for high concentration and high activity interfaces. (2) Limited stability: Nanobubbles generated by a single method are easily affected by the environment and have a short lifespan, which limits their application in scenarios that require long-term effects.

[0008] In summary, existing methods for generating high-concentration nitrogen nanobubbles suffer from technical problems such as low nanobubble concentration and poor stability. Summary of the Invention

[0009] The purpose of this invention is to provide a method and apparatus for generating high-concentration nitrogen nanobubbles based on multi-mechanism synergy, so as to solve the technical problems of low nanobubble generation concentration and poor stability in the prior art.

[0010] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: A method for generating high-concentration nitrogen nanobubbles based on a multi-mechanism synergistic approach includes simultaneously applying nitrogen to a water sample placed in a cavity: Multi-stage eddies are used to generate turbulence and shear forces, as well as to periodically pressurize and depressurize the cavity, inducing the continuous generation of initial nanobubbles in the water sample. During the depressurization process within the cavity, a pulsed electric field synchronized with the frequency and phase of the periodic pressurization and depressurization is applied. The electrical effect generated by the contact between the pulsed electric field and the water sample is used to suppress the aggregation between the interfaces of the continuously generated initial nanobubbles, ultimately obtaining nitrogen nanobubbles of the target concentration.

[0011] As a preferred embodiment of the present invention, the pressure range of the periodic pressurization is 0.2 to 1.2 MPa, the pressure range of the periodic depressurization is 0.08 to 0.12 MPa, and the frequency of the periodic pressurization and depressurization is 0.5 to 15 Hz.

[0012] As a preferred embodiment of the present invention, the electric field strength of the pulsed electric field is 10 to 25 kV / m, and the pulse width is 1 to 150 ms.

[0013] As a preferred embodiment of the present invention, the temperature of the water sample is maintained between 10 and 35 degrees Celsius, and the pH value is between 5.5 and 7.5.

[0014] This invention provides an apparatus for generating high-concentration nitrogen nanobubbles, comprising: A pressure oscillation chamber, wherein the pressure oscillation chamber is provided with an inlet for water sample and an outlet for nitrogen nanobubble water sample of target concentration; A multi-stage vortex system, fixed inside the pressure oscillation chamber, is used to generate turbulence in a water sample flowing through the multi-stage vortex system. A pressure regulation system, connected to the pressure oscillation chamber, is configured to periodically increase and decrease the pressure within the pressure oscillation chamber to generate pressure oscillations within the pressure oscillation chamber; An electric field generating system includes a pair of electrodes disposed opposite each other within the pressure oscillation chamber and a pulse power supply electrically connected to the electrodes; An adaptive control unit is configured to monitor the frequency and phase of the pressure oscillation in real time, and during the pressure oscillation depressurization phase, control the pulse power supply to output a pulse electric field that is synchronized with the frequency and phase of the pressure oscillation.

[0015] As a preferred embodiment of the present invention, the multi-stage vortex system includes at least two stages of vortex guide plates, wherein the vortex guide plates are rotating structures that can be driven to rotate by the flowing water sample, and each stage of the vortex guide plate includes 4 to 8 helical blades.

[0016] As a preferred embodiment of the present invention, the adaptive control unit includes a pressure sensor, a frequency and phase analysis module, and an electric field modulation circuit. The pressure sensor, the frequency and phase analysis module, and the electric field modulation circuit are electrically connected in sequence, and the overall response time of the adaptive control unit is less than 10 milliseconds.

[0017] As a preferred embodiment of the present invention, the adaptive control unit acquires the pressure signal of the pressure oscillation in real time through the pressure sensor, and after the frequency and phase analysis module analyzes the frequency and phase information in the signal, it controls the timing of the application of the pulse electric field output by the pulse power supply to be precisely synchronized with the voltage reduction phase of the pressure oscillation.

[0018] In a preferred embodiment of the present invention, the helical angle of the blades of the vortex guide plate is in the range of 30° to 60°, so as to generate a Reynolds number greater than 10 in the water sample. 4 Strong turbulence.

[0019] Compared with the prior art, the present invention has the following advantages: This invention couples three physical mechanisms—multi-stage eddies, pressure oscillations, and adaptive pulsed electric fields—in a highly synergistic manner. The multi-stage eddies provide high-density, uniformly distributed bubble nucleation precursors for pressure oscillations, greatly improving the nucleation efficiency of nanobubbles. Meanwhile, the pulsed electric field, precisely synchronized with the pressure drop, intervenes at the instant of bubble nucleation, effectively suppressing the agglomeration phenomenon that easily occurs due to excessively high concentrations by stabilizing the newly formed bubbles. This synergistic mechanism of efficient nucleation followed by immediate stabilization breaks through the physical limits of single methods, enabling the concentration of generated nitrogen nanobubbles to be stably reached at extremely high levels.

[0020] The multi-stage eddy current system of the present invention preferably adopts a fluid-driven rotating guide plate design, which eliminates the need for an additional power source, reducing the complexity and energy consumption of the system. At the same time, the electric field is applied in the form of pulses and only operates during a brief decompression phase with an extremely low duty cycle, resulting in a significant reduction in energy consumption compared to a continuously applied static electric field. Attached Figure Description

[0021] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of an apparatus for generating high-concentration nitrogen nanobubbles according to an embodiment of the present invention.

[0023] Figure 2 yes Figure 1 A schematic diagram of the vortex guide plate in the device shown.

[0024] Figure 3 yes Figure 1 The system block diagram of the adaptive control unit in the device shown.

[0025] Figure 4 This is a timing diagram illustrating the adaptive synchronization relationship between pressure oscillation and pulsed electric field in the method of the present invention.

[0026] The labels in the diagram represent the following: 1-Pressure oscillation chamber; 2-Input port; 3-Multi-stage eddy current system; 31-Eddy current guide plate; 4-Pressure regulation system; 5-Electric field generation system; 51-Electrode; 52-Pulse power supply; 6-Adaptive control unit; 61-Pressure sensor; 7-Output port. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, this invention provides a method for generating high-concentration nitrogen nanobubbles based on a multi-mechanism synergy, comprising simultaneously applying: Multi-stage eddies are used to generate turbulence and shear forces, as well as to periodically pressurize and depressurize the cavity, inducing the continuous generation of initial nanobubbles in the water sample. During the depressurization process within the cavity, a pulsed electric field synchronized with the frequency and phase of the periodic pressurization and depressurization is applied. The electrical effect generated by the contact between the pulsed electric field and the water sample is used to suppress the aggregation between the interfaces of the continuously generated initial nanobubbles, ultimately obtaining nitrogen nanobubbles of the target concentration.

[0029] The pressure range for periodic boosting is 0.2 to 1.2 MPa, the pressure range for periodic depressurization is 0.08 to 0.12 MPa, and the frequency of periodic boosting and depressurization is 0.5 to 15 Hz.

[0030] The electric field strength of the pulsed electric field is 10 to 25 kV / m, and the pulse width is 1 to 150 milliseconds.

[0031] The water sample temperature was maintained between 10 and 35 degrees Celsius, and the pH value ranged from 5.5 to 7.5.

[0032] like Figure 1 As shown, the present invention provides an apparatus for generating high-concentration nitrogen nanobubbles, which is used to implement a method for generating high-concentration nitrogen nanobubbles. The apparatus includes: Pressure oscillation chamber 1, which is equipped with a water sample inlet 2 and a nitrogen nanobubble water sample output port 7 of target concentration; A multi-stage vortex system 3 is fixed inside the pressure oscillation chamber 1 and is used to generate turbulence in a water sample flowing through the multi-stage vortex system. The pressure regulation system 4 is connected to the pressure oscillation chamber 1 and is configured to periodically increase and decrease the pressure in the pressure oscillation chamber 1 to generate pressure oscillation in the pressure oscillation chamber 1. The electric field generating system 5 includes a pair of electrodes 51 disposed opposite to each other in the pressure oscillation chamber 1 and a pulse power supply 52 electrically connected to the electrodes 51; The adaptive control unit 6 is configured to monitor the frequency and phase of the pressure oscillation in real time, and during the pressure reduction phase of the pressure oscillation, control the pulse power supply to output a pulse electric field that is synchronized with the frequency and phase of the pressure oscillation.

[0033] In a typical workflow, a pre-prepared nitrogen-supersaturated water sample is first pumped into the top inlet of the pressure oscillating chamber via a water sample input system.

[0034] Inside the cavity, the water sample flows from top to bottom, passing sequentially through a multi-stage vortex system, the core component of which is the vortex guide plate. During this process, the water sample is subjected to intense vortex and shearing forces.

[0035] At the same time, the dynamic pressure regulating valve, which is connected to the side wall of the cavity, applies periodic high and low pressure oscillations to the liquid in the cavity under the command of the adaptive control unit.

[0036] The key innovation of this invention lies in the fact that during the decompression phase of each pressure oscillation cycle, that is, at the instant when a large number of nanobubbles precipitate and nucleate from the supersaturated solution, the adaptive control unit precisely triggers the electric field generator to apply a brief and high-intensity electric field pulse to the liquid through its internal electrodes.

[0037] This synchronized electric field pulse effectively stabilizes the newly formed nanobubbles, preventing them from coalescing. Ultimately, the high-concentration, highly stable nanobubble water sample generated after this series of multi-physics synergistic effects is collected through the output port and output system at the bottom of the cavity and can be directly used for subsequent applications.

[0038] The multi-stage vortex system 3 in this embodiment includes at least two stages of vortex guide plates 31. Each vortex guide plate 31 is a rotating structure that can be driven to rotate by the flowing water sample, and each stage of the vortex guide plate 31 includes 4 to 8 helical blades.

[0039] The blades of the vortex guide vane 31 have a helical angle ranging from 30° to 60° to generate a Reynolds number greater than 10 in the water sample. 4 Strong turbulence.

[0040] The adaptive control unit 6 includes a pressure sensor 61, a frequency and phase analysis module, and an electric field modulation circuit. The pressure sensor 61, the frequency and phase analysis module, and the electric field modulation circuit are electrically connected in sequence, and the overall response time of the adaptive control unit 6 is less than 10 milliseconds.

[0041] The adaptive control unit 6 collects the pressure signal of the pressure oscillation in real time through the pressure sensor 61. After the frequency and phase analysis module analyzes the frequency and phase information in the signal, it controls the timing of the application of the pulse electric field output by the pulse power supply to be precisely synchronized with the pressure reduction phase of the pressure oscillation.

[0042] Detailed descriptions of each system: (1) Multistage eddy current and pressure oscillation system The pressure oscillation chamber 1 is preferably made of a corrosion-resistant material capable of withstanding high pressure (e.g., pressure resistance of 2-2.5 MPa), such as 316L stainless steel. Its internal structure is designed as a cylinder, and its size can be adjusted according to the processing scale. For example, a laboratory-scale design with an inner diameter of 20 cm and a height of 30 cm can be adopted.

[0043] like Figure 2 As shown, the vortex guide plate is one of the key structures for achieving efficient nucleation in this invention. Its unique feature lies in the adoption of a multi-stage fluid-driven rotation design.

[0044] In a preferred embodiment, a three-stage vortex guide vane is arranged in the cavity along the water flow direction, with a certain distance (e.g., 5 cm) between each stage to ensure that the flow field is fully developed.

[0045] Each stage of the deflector consists of multiple blades (e.g., 4-8 blades, preferably 6 blades) with a specific helical angle (e.g., 30°-60°, preferably 50°). The blades can be made of polytetrafluoroethylene (PTFE) or corrosion-resistant stainless steel.

[0046] When a water sample flows through it at a certain velocity, its kinetic energy drives the guide vane to rotate around its central axis (for example, at a speed of 50-200 rpm), thereby generating strong shear forces and eddy currents locally. This design allows the fluid to reach a highly turbulent state with a high Reynolds number (Re>104).

[0047] Strong turbulence greatly enhances the micro-mixing and mass transfer efficiency of the gas-liquid two phases, effectively "stirring" nitrogen molecules dissolved in water out of the supersaturated state, creating a large number of tiny and uniformly distributed gas evolution nuclei (i.e. bubble nuclei) for explosive nucleation during subsequent pressure drop.

[0048] Compared with static mixers or single-stage vortex devices that rely on fixed blades in the prior art, the multi-stage, dynamic rotating vortex design of the present invention can generate high-density bubble nuclei more efficiently, laying the foundation for ultimately obtaining high-concentration nanobubbles.

[0049] The pressure regulation system mainly consists of a dynamic pressure regulating valve. One end of the valve is connected to a high-pressure nitrogen source (e.g., a maximum pressure of 10 MPa), and the other end is connected to a vacuum pump (e.g., a minimum pressure of 0.05 MPa). This valve is electromagnetically controlled by an adaptive control unit, enabling millisecond-level (e.g., response time less than 5 milliseconds) rapid switching, thereby precisely achieving periodic pressure oscillations within the chamber. Oscillation parameters, such as the pressurization range, depressurization range, and oscillation frequency, can all be set via the control unit.

[0050] (2) Adaptive pulse electric field system The electric field generator includes a pair of parallel plate electrodes and a pulsed power supply for powering them. In a preferred embodiment, the electrodes are spaced 3-10 mm apart (preferably 8 mm) and are made of metal plates coated with a polytetrafluoroethylene (PTFE) insulating and corrosion-resistant layer with a thickness of about 0.1 mm.

[0051] The PTFE coating not only effectively prevents the electrode from being corroded or undergoing electrochemical side reactions in an aqueous environment, but also provides excellent electrical insulation, reduces the leakage of electric field energy, and ensures that the electric field acts stably on the target area.

[0052] The pulse power supply can output a high voltage pulse with specific parameters when triggered by the control unit. Its output capability should be able to generate an electric field strength of 10-25kV / m between the electrodes, and the pulse width and frequency can be adjusted.

[0053] like Figure 3 and Figure 4 As shown, the adaptive control unit is the core technology of this invention and the key to realizing its inventiveness. It ensures perfect temporal coordination between the electric field stabilization effect and the pressure-induced nucleation process. This unit mainly includes a high-precision pressure sensor 61, a frequency and phase analysis module, and an electric field modulation and triggering circuit.

[0054] A pressure sensor 61, such as a piezoelectric pressure sensor or a MEMS pressure sensor with high frequency response characteristics, is mounted on the pressure oscillation chamber 1 to monitor the dynamic change waveform of the pressure P(t) in the chamber in real time.

[0055] The frequency and phase analysis module receives continuous signals from pressure sensor 61. This module integrates advanced signal processing algorithms, such as a phase-locked loop (PLL) algorithm. The PLL algorithm uses the periodic pressure waveform signal as an input reference signal and, through an internal oscillator and phase detector, quickly locks the frequency f and phase φ of the input signal. After locking, the module can generate a logic control signal that is strictly synchronized with the pressure signal.

[0056] The electric field modulation and triggering circuit receives the synchronization logic signal from the frequency and phase analysis module.

[0057] like Figure 4 As shown, the circuit is configured to precisely send a trigger signal to the pulse power supply 22 at the moment when the pressure drops to the trough (Pmin) in each pressure cycle, which is the moment when bubble nucleation is most intense and the newly formed bubbles are most unstable.

[0058] The trigger signal controls the pulse power supply to apply an electric field pulse E(t) with a preset intensity (e.g., Epulse) and width (e.g., tpulse). The response time of the entire control loop is extremely short (e.g., less than 10 milliseconds), ensuring the immediacy of the electric field application.

[0059] Electric field stabilization mechanism: The mechanism of this pulsed electric field, which is precisely synchronized with the nucleation process, is to use the interaction between the electric field and the newly formed nanobubbles to suppress their aggregation.

[0060] Specifically, when an electric field is applied, due to the difference in dielectric constants between water molecules and nitrogen molecules, a dielectric electrophoresis effect is generated at the bubble-water interface, which induces a dipole moment on the bubble surface.

[0061] Simultaneously, the electric field induces surface polarization, leading to the redistribution and enrichment of ions at the interface (primarily OH⁻ ions in water), thereby significantly enhancing the negative charge density on the bubble surface. This enhanced surface charge results in a substantial increase in the absolute value of the bubble's Zeta potential (e.g., from a lower value to -25 mV or even lower).

[0062] According to the DLVO theory of colloidal stability, the higher the absolute value of the Zeta potential, the stronger the electrostatic repulsion between bubbles, which can effectively overcome van der Waals attraction, prevent bubbles from getting close to each other and merging, and ensure the high stability and size uniformity of the generated bubbles.

[0063] Parameter range: To achieve the best results of this invention, the operating parameters can be optimized within a certain range. Table 2 below summarizes the preferred parameter ranges for the method and apparatus of this invention.

[0064] Table 2 parameter scope Preferred range Corresponding values ​​in the example Pressurization pressure (MPa) 0.2-1.2 0.6-1.0 0.6,1.0,0.8 Pressure reduction (MPa) 0.08-0.12 0.08 0.1,0.08 Pressure oscillation frequency (Hz) 0.5-15 1-5 1,5,2 Electric field strength (kV / m) 10-25 15-20 15,20,18 Electric field pulse width (ms) 1-150 20-50 20,50,30 Water sample temperature (°C) 10-35 25 25,10 pH value of water sample 5.5-7.5 7.0 7.0 Example To further illustrate the present invention, specific embodiments are described below. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0065] Example 1: Laboratory-scale generation Experimental setup: A 500mL 316L stainless steel pressure oscillation chamber 1, pressure resistant to 2MPa, was used. Two stages of vortex guide vanes, each with 4 blades and a helical angle of 45°, were installed inside the chamber, made of polytetrafluoroethylene (PTFE). The pressure regulation system consisted of a dynamic pressure regulating valve with a response time of less than 5 milliseconds, a high-pressure nitrogen source, and a vacuum pump. The electric field generator used parallel plate electrodes with a spacing of 5 mm and a PTFE-coated surface, powered by a pulse power supply with a maximum output of 30kV / m. The adaptive control unit was equipped with a pressure sensor 61 with an accuracy of ±0.001MPa and a frequency analysis module.

[0066] Experimental steps: (1) Water sample preparation: Take 500 mL of deionized water with a resistivity of not less than 18.2 MΩ·cm, and introduce nitrogen gas with a purity of 99.999% at a pressure of 8 MPa through high pressure injection. Stir and dissolve for 30 minutes to prepare nitrogen-saturated water sample.

[0067] (2) Injection and oscillation: Inject the prepared water sample into the pressure oscillation chamber 1, start the pressure regulation system, and set the pressure oscillation parameters: pressurize to 0.6MPa, then depressurize to 0.1MPa, oscillation frequency is 1Hz, and cycle 20 times.

[0068] (3) Synchronous electric field application: During each decompression stage, a pulse electric field is triggered by the adaptive control unit, with the electric field strength set to 15kV / m, the pulse width to 20 milliseconds, and the frequency synchronized with the pressure oscillation (1Hz).

[0069] (4) Detection: After processing, samples are taken from output port 7 and the concentration, size distribution and zeta potential of nanobubbles are detected using a dynamic light scattering instrument (DLS, such as Malvern Zetasizer Pro). The long-term stability of the samples is also observed.

[0070] Results: The concentration of generated nitrogen nanobubbles was 5.2 × 10¹⁴ bubbles / mL, with an average size ranging from 80 to 150 nm, and a Zeta potential of -28 mV. After the sample was sealed and stored at room temperature for 6 months, the concentration was measured again, showing a decrease of less than 10%, demonstrating extremely high stability.

[0071] Example 2: Industrialized Optimized Production Experimental setup: A 5-liter 316L stainless steel pressure oscillation chamber 1, pressure resistant to 2.5 MPa, is used. A three-stage stainless steel vortex guide plate is installed inside the chamber, each stage containing 6 blades with a helical angle of 50°. The pressure regulation system uses a high-precision servo control valve with an adjustable frequency up to 15 Hz. The electric field generator has an electrode spacing of 8 mm and an intensity of up to 25 kV / m. The response time of the adaptive control unit is optimized to less than 2 milliseconds.

[0072] Experimental steps: (1) Water sample preparation: Take 5 liters of deionized water and inject nitrogen gas at a pressure of 10 MPa to prepare a saturated water sample. The water sample temperature is controlled at 25°C and the pH value is 7.0.

[0073] (2) Injection and oscillation: Inject the water sample into the pressure oscillation chamber 1 and set the optimized process parameters: pressurize to 1.0 MPa, depressurize to 0.08 MPa, increase the oscillation frequency to 5 Hz, and cycle 50 times.

[0074] (3) Synchronous electric field application: During the decompression phase, an adaptive pulse electric field is applied with an intensity of 20kV / m, a pulse width of 50 milliseconds, and a frequency synchronized with the pressure oscillation (5Hz).

[0075] (4) Detection: In addition to DLS detection, cryo-fracture transmission electron microscopy (FF-TEM) was used to observe the morphology of the bubbles.

[0076] Results: DLS analysis showed a high nanobubble concentration of 1.3 × 10¹⁵ cells / mL, with a smaller average size concentrated in the 60-120 nm range. The zeta potential reached -32 mV. FF-TEM images clearly showed the spherical nanobubble structure. After 8 months of sample storage, the concentration decreased by less than 5%, indicating further improved stability.

[0077] Example 3: Adaptability Test to Complex Aquatic Environments Experimental conditions: To simulate a real-world application environment, this embodiment uses tap water containing a small amount of impurities (e.g., 0.1% inorganic salts) as the water sample and conducts the experiment at a relatively low temperature (10°C). The pressure oscillation parameters are set as follows: pressurization 0.8 MPa, depressurization 0.1 MPa, frequency 2 Hz. The electric field parameters are: intensity 18 kV / m, pulse width 30 milliseconds.

[0078] Results: Even under relatively harsh conditions, the method of this invention still exhibits good performance. The concentration of generated nanobubbles is approximately 8.7 × 10¹⁴ bubbles / mL, with a slightly broadened size distribution ranging from 70 to 180 nm. Stability testing showed that the concentration decreased by approximately 8% after 3 months. These results indicate that the technology of this invention has good environmental adaptability and robustness.

[0079] Performance Results Summary Table 3 below summarizes the main performance results obtained from the above three embodiments, intuitively demonstrating the excellent performance of the present invention under different conditions.

[0080] Table 3 Industrial applicability: The method and apparatus of this invention, due to their ability to efficiently and with low consumption prepare high-concentration, highly stable nitrogen nanobubbles, have significant industrial applicability and broad application prospects in the following fields: 1. Water Treatment: The generated high-concentration nitrogen nanobubbles can be used for wastewater purification, particularly for the remediation of anoxic or anaerobic water bodies. Their large specific surface area serves as a carrier for microbial attachment, while the slowly released nitrogen can provide a nitrogen source for specific microorganisms or remove suspended solids through physical processes (such as flotation). In advanced oxidation processes, nanobubbles can improve the mass transfer efficiency of oxidants such as ozone, promoting the degradation of organic pollutants. Suitable for wastewater treatment plants, river and lake remediation, and other similar applications.

[0081] 2. Agriculture: Using water containing high concentrations of nitrogen nanobubbles for irrigation can significantly improve soil looseness and oxygen content, improve the rhizosphere microenvironment, promote root respiration and nutrient absorption, thereby increasing crop yield and quality. This "nanobubble water" is particularly valuable for modern precision agriculture and facility agriculture.

[0082] 3. Biomedical field: High-concentration, highly stable nitrogen nanobubbles can be used as an optimized additive for cell culture media, improving cell density and the yield of fermentation products (such as antibodies and vaccines) by enhancing gas exchange efficiency. Furthermore, due to their small size and surface functionalizability, they can also serve as novel drug or gene delivery carriers for targeted therapy.

[0083] 4. Oil and Gas Extraction: In tertiary oil recovery technology, high-concentration nitrogen nanobubble suspensions are injected into the reservoir. Nanobubbles can penetrate micropores and throats that are difficult to reach using conventional methods. Through multiple mechanisms such as reducing oil-water interfacial tension, altering rock wettability, and the Jamin effect, they displace residual oil adsorbed on the rock surface, thereby effectively improving oilfield recovery and increasing crude oil production.

[0084] In summary, this invention, through its unique multi-stage eddy current design and innovative adaptive electric field control technology, successfully solves the core challenges of existing technologies in nanobubble generation. The provided method and apparatus not only have significant technical effects but also possess excellent industrial applicability and promotion potential.

[0085] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A method for generating high-concentration nitrogen nanobubbles based on multi-mechanism synergy, characterized in that, This includes simultaneously applying supersaturated dissolved nitrogen gas to a water sample flowing into a cavity: Multi-stage eddies are used to generate turbulence and shear forces, as well as to periodically pressurize and depressurize the cavity, inducing the continuous generation of initial nanobubbles in the water sample. During the depressurization process within the cavity, a pulsed electric field synchronized with the frequency and phase of the periodic pressurization and depressurization is applied. The electrical effect generated by the contact between the pulsed electric field and the water sample is used to suppress the aggregation between the interfaces of the continuously generated initial nanobubbles, ultimately obtaining nitrogen nanobubbles of the target concentration.

2. The method for generating high-concentration nitrogen nanobubbles based on multi-mechanism synergy according to claim 1, characterized in that, The periodic pressurization pressure range is 0.2 to 1.2 MPa, the periodic depressurization pressure range is 0.08 to 0.12 MPa, and the periodic pressurization and depressurization frequency is 0.5 to 15 Hz.

3. The method for generating high-concentration nitrogen nanobubbles based on multi-mechanism synergy according to claim 1, characterized in that, The electric field strength of the pulsed electric field is 10 to 25 kV / m, and the pulse width is 1 to 150 milliseconds.

4. The method for generating high-concentration nitrogen nanobubbles based on multi-mechanism synergy according to claim 1, characterized in that, The water samples were maintained at a temperature of 10 to 35 degrees Celsius and a pH value of 5.5 to 7.

5.

5. A high-concentration nitrogen nanobubble generation device based on multi-mechanism synergy for implementing the high-concentration nitrogen nanobubble generation method based on multi-mechanism synergy according to any one of claims 1-4, characterized in that, include: The pressure oscillation chamber (1) is provided with an inlet (2) for water sample and an outlet (7) for nitrogen nanobubble water sample of target concentration. A multi-stage vortex system (3) is fixed inside the pressure oscillation chamber (1) and is used to generate turbulence in the water sample flowing through the multi-stage vortex system; The pressure regulation system (4), connected to the pressure oscillation chamber (1), is configured to periodically increase and decrease the pressure in the pressure oscillation chamber (1) to generate pressure oscillation in the pressure oscillation chamber (1); The electric field generating system (5) includes a pair of electrodes (51) disposed opposite each other in the pressure oscillation chamber (1) and a pulse power supply (52) electrically connected to the electrodes (51). An adaptive control unit (6) is configured to monitor the frequency and phase of the pressure oscillation in real time, and during the pressure oscillation depressurization phase, control the pulse power supply to output a pulse electric field that is synchronized with the frequency and phase of the pressure oscillation.

6. The high-concentration nitrogen nanobubble generation device based on multi-mechanism synergy according to claim 5, characterized in that, The multi-stage vortex system (3) includes at least two stages of vortex guide plates (31), which are rotating structures that can be driven to rotate by the flowing water sample, and each stage of the vortex guide plate (31) includes 4 to 8 helical blades.

7. The high-concentration nitrogen nanobubble generation device based on multi-mechanism synergy according to claim 5, characterized in that, The adaptive control unit (6) includes a pressure sensor (61), a frequency and phase analysis module, and an electric field modulation circuit. The pressure sensor (61), the frequency and phase analysis module, and the electric field modulation circuit are electrically connected in sequence, and the overall response time of the adaptive control unit (6) is less than 10 milliseconds.

8. The high-concentration nitrogen nanobubble generation device based on multi-mechanism synergy according to claim 7, characterized in that, The adaptive control unit (6) collects the pressure signal of the pressure oscillation in real time through the pressure sensor. After the frequency and phase analysis module analyzes the frequency and phase information in the signal, it controls the timing of the application of the pulse electric field output by the pulse power supply to be precisely synchronized with the voltage reduction phase of the pressure oscillation.

9. The high-concentration nitrogen nanobubble generation device based on multi-mechanism synergy according to claim 6, characterized in that, The blades of the vortex guide plate (31) have a helical angle ranging from 30° to 60° to generate a Reynolds number greater than 10 in the water sample. 4 Strong turbulence.

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