Confined flow type ultrasonic enhanced ozone oxidation microbubble reactor and application

Abstract

The invention belongs to the technical field of microreactors and advanced oxidation water treatment, and discloses a confinement flow type ultrasonic enhanced ozone oxidation microbubble reactor and application, the confinement flow type ultrasonic enhanced ozone oxidation microbubble reactor comprises an ultrasonic assembly, a conveying assembly and an ozone assembly, the conveying assembly is arranged on the ultrasonic assembly, and the ozone assembly is arranged in the conveying assembly; the reaction liquid containing the pollutants flows in the conveying assembly and is in contact with the ozone microbubbles, so that the degradation of the pollutants is realized. According to the ultrasonic-ozone coupling system, the problems that in an existing ultrasonic-ozone coupling system, due to uncontrollable bubble behaviors and low sound-gas coupling efficiency, the ozone mass transfer and utilization efficiency is bottleneck, and due to the fact that the system is complex and depends on external conditions, the economical efficiency and applicability are poor are solved; the efficient, stable and reinforced coupling of the micron-sized ozone bubbles and the ultrasonic cavitation field is realized, so that the treatment capacity and the operation benefit of refractory organic pollutants are remarkably improved by a simple, reliable and low-cost technical path.

Description

Technical Field

[0001] This invention belongs to the field of microreactors and advanced oxidation water treatment technology, specifically relating to a confined flow ultrasonic-enhanced ozone oxidation microbubble reactor and its application. Background Technology

[0002] Ozone degrades pollutants primarily through its powerful oxidizing ability. Ozone molecules can break down pollutants through two pathways: one is direct oxidation, where ozone attacks unsaturated bonds or specific functional groups in organic molecules; the other is indirect oxidation, where ozone decomposes in water into more potent hydroxyl radicals (·OH), which react with the vast majority of organic compounds.

[0003] The combined use of ozone and ultrasound technology demonstrates significant advantages in treating recalcitrant organic pollutants through the synergistic effect of acoustic cavitation and advanced oxidation. This technology generates a localized high-temperature, high-pressure environment through cavitation, which can directly pyrolyze organic matter, break down water molecules to produce hydroxyl radicals, and greatly accelerate the rate and efficiency of ozone decomposition to generate strong oxidizing radicals. Furthermore, the breaking and dispersing effect of ultrasound on ozone bubbles overcomes the core bottlenecks of low mass transfer efficiency and limited solubility in traditional ozone technologies.

[0004] Currently, traditional ultrasound-ozone coupling systems are mostly carried out in open or semi-open reactors. Ozone bubbles tend to grow and coalesce freely in the liquid phase, often forming large bubbles in the millimeter size. This results in problems such as short contact time with water, low ozone dissolution efficiency, and difficulty in resonating and matching bubble size with ultrasonic frequency, which severely limits the enhancement effect of cavitation and the utilization efficiency of ozone.

[0005] Among existing publicly available technologies, the closest to this invention is patent CN116986708A, which discloses a solar-powered industrial wastewater treatment system using ultrasonically coupled ozone micro-nano bubbles. This system includes an industrial wastewater treatment chamber, an ozone micro-nano bubble generating module, an ultrasonic vibration generating module, and a solar power supply module. It utilizes ultrasonic cavitation to promote pollutant dispersion and enhances ozone dissolution and mass transfer efficiency through micro-nano bubbles, thereby improving oxidative degradation performance. However, this technology suffers from the following core defects: 1. The reaction chamber is a macroscopically open structure, lacking physical constraints on bubble behavior. Ozone bubbles easily grow freely, coalesce, and rapidly rise and escape within the reaction chamber, making it impossible to stably control the bubble size at the micrometer level to match the ultrasonic field resonance. The residence time of bubbles within the ultrasonic action area is extremely short, resulting in extremely low sound-gas coupling efficiency. 2. The system structure is cumbersome, relying on catalysts, solar power supply units, and complex monitoring and control modules. This leads to high equipment manufacturing costs and maintenance difficulties, and it cannot achieve continuous and efficient coupling between microbubbles and the sound field within a confined space, making it unsuitable for continuous flow and compact water treatment scenarios. In addition, patent CN114477376A discloses a water treatment device and its operation method based on ozone nano-microbubble "core injection" stacked double hollow fiber membrane technology. The system adopts a double-layer hollow fiber membrane structure. When ozone passes through the inner membrane, it generates nano-microbubbles and reacts with the wastewater flowing through the cavity between the membranes. Its membrane material contains transition metals such as Fe, Cr or Ni, aiming to utilize the "confined effect" of the membrane pores to catalyze ozone decomposition, enhance mass transfer and control membrane fouling. However, this technology still has significant limitations: First, its "confined domain" mainly refers to the nanoscale space inside the membrane pores, aiming at catalysis rather than actively constraining the macroscopic dynamics of bubbles. Bubbles in the inter-membrane cavity are still prone to coalescence and escape, lacking continuous control over bubble size, movement, and collapse processes. Second, the system relies entirely on ozone oxidation and metal catalysis, without introducing an ultrasonic cavitation field, making it impossible to further break up bubbles, generate hydroxyl radicals, and enhance mass transfer through cavitation effects. Third, the device has a complex structure, relies on specific catalytic membrane materials, and suffers from membrane fouling, catalytic performance degradation, and replacement costs. Furthermore, the operation mode is intermittent drainage, making it difficult to achieve efficient and low-consumption continuous flow treatment.

[0006] Based on this, existing ultrasonic-ozone coupling technology still cannot solve the core problems of uncontrollable bubble behavior, low acoustic-gas coupling efficiency, poor ozone mass transfer and utilization efficiency, and complex system structure with weak applicability. There is an urgent need to develop a new type of ultrasonic-ozone coupling reactor to break through the bottleneck of existing technology. Summary of the Invention

[0007] Addressing the core shortcomings of existing technologies, such as the tendency of bubbles to coalesce and escape in open chambers, low acoustic-gas coupling efficiency, complex system structure, and inability to adapt to continuous flow compact processing scenarios, as well as the common problems of low ozone mass transfer and utilization efficiency, insufficient free radical generation efficiency, and dependence on catalysts and complex auxiliary units in existing ultrasonic-ozone coupling technologies, the present invention aims to provide a confined flow ultrasonic-enhanced ozone oxidation microbubble reactor and its application. Through the "confined flow" physical structure, it achieves efficient, stable, and enhanced coupling between micron-sized ozone bubbles and ultrasonic cavitation fields, breaking through the bottleneck of ozone mass transfer and utilization efficiency. At the same time, it achieves efficient and continuous treatment of recalcitrant organic pollutants with a simple and low-cost structure.

[0008] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a confined flow ultrasonic-enhanced ozone oxidation microbubble reactor, comprising: Ultrasonic components; The delivery assembly includes a reaction tube and a connecting tube. The outer wall of the reaction tube is tightly coupled to the ultrasonic component. The ultrasonic component transmits sound waves to the liquid phase inside the reaction tube. One end of the reaction tube serves as the reaction liquid outlet, and the other end serves as the docking interface. The connecting tube includes a main tube and a branch tube. The branch tube is located on the side of the main tube. One end of the branch tube serves as the reaction liquid inlet. One end of the main tube is connected to the docking interface of the reaction tube, and the other end of the main tube is closed. The ozone module includes a gas delivery pipe and a microporous aerator head. The microporous aerator head is disposed inside the reaction tube, and the gas delivery pipe passes through the main pipe of the connecting pipe. One end of the gas delivery pipe is connected to the microporous aerator head, and the other end of the gas delivery pipe extends out from the closed end of the main pipe. There is a liquid delivery gap between the outer wall of the gas delivery pipe and the inner wall of the main pipe, and there is a confining gap between the microporous aerator head and the inner wall of the reaction tube. The liquid delivery gap is connected to the confining gap through the interface of the reaction tube, forming a flow channel for continuous flow of reaction liquid.

[0009] Preferably, the confinement gap is ≤1.25 mm.

[0010] Preferably, the pore size of the microporous aerator head is 1~300μm.

[0011] Preferably, the ultrasonic frequency of the ultrasonic transducer is 15 kHz to 1 MHz.

[0012] Preferably, the inner diameter of the reaction tube is 0.3~25 mm.

[0013] Preferably, the reaction tube is a circular straight tube, the microporous aeration head has a cylindrical shape, and the reaction tube and the microporous aeration head are coaxially arranged, forming an annular confining gap between the inner wall of the reaction tube and the outer wall of the microporous aeration head.

[0014] More preferably, the circumferential side surface of the microporous aeration head and the end face of the microporous aeration head away from the air supply pipe are each uniformly provided with multiple micron-sized pores.

[0015] Preferably, the ultrasonic component includes an ultrasonic transducer.

[0016] In a second aspect, the present invention proposes an application of a confined flow ultrasonic-enhanced ozone oxidation microbubble reactor, including its application in the continuous flow treatment of recalcitrant organic pollutant wastewater.

[0017] Preferably, the organic pollutant degradation treatment method using the above-mentioned confined flow ultrasonic-enhanced ozone oxidation microbubble reactor includes the following steps: S1. The reaction liquid containing organic pollutants is fed into the reactor from the reaction liquid inlet of the branch pipe in a continuous flow manner, and enters the flow channel of the confined gap through the liquid delivery gap; S2. Ozone gas is introduced into the microporous aerator through the gas delivery pipe, and continuously injected into the reaction liquid in the confined gap in the form of micron-sized bubbles through the pores of the microporous aerator. S3. Activate the ultrasonic component to apply ultrasonic waves into the reaction tube. By adjusting the ozone dosage, reaction liquid flow rate, ultrasonic power, and hydraulic residence time, the organic pollutants in the reaction liquid are continuously degraded and mineralized.

[0018] Beneficial effects: This invention achieves effective resonance with ultrasonic frequencies by suppressing the free growth and aggregation of ozone bubbles, stabilizing their size at the micrometer level and making them concentrated. Secondly, the narrow, confined space within the reaction tube significantly slows down the rising speed of the bubbles, prolonging the contact and reaction time between ozone and pollutants. Furthermore, the constrained microbubble clusters are continuously within the range of a strong ultrasonic field, making them easier to capture and undergo continuous oscillation, growth, and violent collapse, thereby significantly enhancing the cavitation effect locally.

[0019] The structure of this invention is extremely simple, mainly consisting of core components such as an ultrasonic transducer, a reaction tube, and a microporous aeration head. It does not rely on catalysts, additional energy fields, or complex auxiliary units. While improving ozone utilization efficiency and pollutant degradation performance, it enhances the system's operational reliability, economy, and process versatility. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view of the confined flow ultrasonic-enhanced ozone oxidation microbubble reactor described in this invention.

[0021] Figure 2 The graph shows the effect of the confined gap on the degradation rate of fumaric acid in Example 1.

[0022] Figure 3 The graph shows the effect of the confined gaps on the degradation rate of terephthalic acid in Example 2.

[0023] Figure 4 This is a graph showing the effect of the confined gap on the degradation rate of Rhodamine B in Example 3.

[0024] Figure 5 This is a comparison chart showing the effect of ultrasonic treatment at different oxygen flow rates on the dissolved oxygen concentration in deionized water in Example 4.

[0025] Figure 6 This is a comparison of the ultraviolet absorption of ozone solution at 190 nm and 260 nm with and without ultrasonic treatment in Example 4.

[0026] Figure 7 This is a comparison chart showing the effects of different treatment methods on the degradation rate of fumaric acid in Example 5.

[0027] Figure 8 This is a comparison chart showing the effects of different treatment methods on the degradation rate of terephthalic acid in Example 6.

[0028] Figure 9 This is a comparison chart showing the effects of different treatment methods on the degradation rate of Rhodamine B in Example 7.

[0029] Explanation of reference numerals in the attached diagram: 1-ultrasonic transducer, 2-reaction tube, 3-connecting tube, 31-main tube, 32-branch tube, 4-gas delivery tube, 5-microporous aeration head, 6-limiting gap, 7-infusion gap. Detailed Implementation

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0031] A comprehensive analysis of existing ultrasound-ozone coupled water treatment technologies reveals that further improvements in their efficiency are generally limited by an unavoidable contradiction: the macroscopic free motion of ozone bubbles and the microscopic cavitation energy field are difficult to couple continuously, stably, and efficiently in space. This invention proposes a confined-flow ultrasound-enhanced ozone oxidation microbubble reactor, which solves the above problem. The reactor of this invention has a simple structure and can achieve precise control over the entire process of ozone bubble generation, motion, and collapse, enabling high-intensity, continuous, and stable fusion with the high-energy-density ultrasonic cavitation field in space and time. This fundamentally synergistically enhances the mass transfer, dissolution, and free radical conversion pathways of ozone.

[0032] The overall structure of the reactor, such as Figure 1 As shown, the confined flow ultrasonic-enhanced ozone oxidation microbubble reactor of the present invention includes an ultrasonic component, a conveying component, and an ozone component. The conveying component is fixedly mounted on the ultrasonic component, and the ozone component is coaxially inserted inside the conveying component. The reaction liquid containing organic pollutants flows continuously within the conveying component, fully contacting and reacting with the ozone microbubbles to achieve continuous degradation of the pollutants. The technical solution of the present invention will be described in detail below with reference to the specific structure.

[0033] like Figure 1 As shown, the ultrasonic component includes an ultrasonic transducer for generating ultrasonic waves of a specific frequency, which is the energy source for the ultrasonic cavitation field. In this invention, the ultrasonic transducer can be a ceramic-pressed ultrasonic transducer with an operating frequency covering 15kHz to 1MHz and a rated power range of 10 to 200 W.

[0034] like Figure 1 As shown, the delivery assembly includes a reaction tube and a connecting tube. The outer wall of the reaction tube is tightly coupled to an ultrasonic transducer, which transmits sound waves to the liquid phase inside the reaction tube. One end of the reaction tube serves as the reaction liquid outlet, and the other end serves as the connection port. The connecting tube includes a main pipe and a branch pipe. The branch pipe is located on the side of the main pipe, with one end serving as the reaction liquid inlet. One end of the main pipe connects to the connection port of the reaction tube, and the other end of the main pipe is closed. The flow direction of the reaction liquid in the delivery assembly is as follows: the reaction liquid enters the delivery assembly from the reaction liquid inlet of the branch pipe of the connecting tube, flows into the reaction tube along the branch pipe and the main pipe, and finally flows out from the reaction liquid outlet of the reaction tube. For the reaction liquid, this invention adopts continuous flow operation, which can realize continuous flow of the reaction liquid within the delivery assembly. It is easy to understand that connectors can be provided at the reaction liquid outlet of the reaction tube and at the reaction liquid inlet of the branch pipe for connection to external equipment.

[0035] After the outer wall of the reaction tube is polished, it is tightly bonded to the radiation surface of the ultrasonic transducer with epoxy resin-based ultrasonic adhesive. The adhesive layer thickness is ≤0.1 mm, which ensures that the ultrasonic energy is efficiently transmitted to the liquid phase inside the reaction tube, forming a uniform and high-intensity ultrasonic cavitation field throughout the entire cavity of the reaction tube.

[0036] like Figure 1 As shown, the ozone module includes a gas delivery pipe and a microporous aerator head. The microporous aerator head is disposed inside the reaction tube, and the gas delivery pipe passes through the main pipe of the connecting pipe. One end of the gas delivery pipe is connected to the microporous aerator head, and the other end of the gas delivery pipe extends out from the closed end of the main pipe. There is a liquid delivery gap between the outer wall of the gas delivery pipe and the inner wall of the main pipe, and there is a confining gap between the microporous aerator head and the inner wall of the reaction tube. The liquid delivery gap is connected to the confining gap through the interface of the reaction tube, forming a flow channel for continuous flow of reaction liquid.

[0037] In this invention, the connections between different components are sealed. For example, one end of the main pipe is sealed to the interface of the reaction tube, one end of the gas delivery pipe is sealed to the microporous aerator head, and the other end of the gas delivery pipe extends out from the sealed end of the main pipe, maintaining a sealed state at the exit point. Further details of this invention will not be elaborated further.

[0038] In existing open or semi-open reactors, once ozone bubbles are generated, they grow freely, coalesce, and rapidly escape under the influence of buoyancy and fluid. This unrestrained movement results in a wide bubble size distribution and a short residence time within the ultrasonic field. This not only severely limits the dissolution and mass transfer efficiency of ozone but also makes it difficult for bubbles to form and maintain effective resonance matching with ultrasonic fields of specific frequencies. The essence of this invention is a highly integrated multi-physics coupling reaction unit that, through ingenious spatial structure design, integrates three major functions: micron-level bubble generation, ultrasonic cavitation field application, and bubble behavior confinement.

[0039] This invention places the microporous aerator, the source of micron-sized ozone bubbles, directly in the core region of a uniform and high-intensity cavitation field excited by an ultrasonic transducer. Through the narrow annular gap of adjustable size formed between the outer wall of the microporous aerator and the inner wall of the reaction tube, the nascent ozone bubbles are subjected to close physical boundary constraints.

[0040] The specific structural features of this invention are as follows: The reaction tube in the delivery assembly serves as the core reaction chamber, and its inner wall constitutes the main physical boundary for the movement of ozone bubbles. The outside of the reaction tube is tightly coupled with the ultrasonic transducer, for example, through grinding and bonding with ultrasonic-specific adhesive, to ensure that ultrasonic energy is efficiently transmitted to the reaction liquid inside the reaction tube, forming a uniform and high-intensity cavitation field.

[0041] The microporous aeration head has micron-sized pores. Ozone forms micron-sized ozone bubbles through the microporous aeration head. A confining gap is formed between the microporous aeration head and the reaction tube, which physically constrains the nascent bubbles generated from the microporous aeration head, inhibits their free growth and aggregation, and forces the bubbles to move within the narrow space, i.e., the confining gap. This stabilizes the bubble size, prolongs the gas-liquid contact time, and makes the bubbles easier to be captured by the ultrasonic field.

[0042] The working principle of this invention is as follows: When the reaction liquid is fed into the device, the reaction liquid to be treated continuously flows into the confined gap of the reaction tube. At the same time, ozone gas enters the microporous aerator head through the gas delivery pipe and is injected into the reaction liquid in the confined gap in the form of micron-sized bubbles. These nascent microbubbles immediately enter the physical space confined by the confined gap and filled with high-intensity ultrasonic activation. Under this environment: Enhanced physical mass transfer: The rising speed of the confined microbubble clusters is slowed down and the residence time is prolonged; at the same time, the microjets and violent disturbances generated by ultrasonic cavitation continuously renew the gas-liquid interface, which greatly promotes the dissolution and mass transfer of ozone gas to the reaction liquid.

[0043] Chemical oxidation activation: The confined microbubbles serve as ideal gas nuclei, continuously undergoing intense oscillations and asymmetric collapse in the ultrasonic field (due to their proximity to the wall). The local extreme high temperature and high pressure conditions generated by the collapse, as well as the strong hydraulic shear, not only directly pyrolyze some pollutants, but also efficiently promote the decomposition of dissolved ozone molecules, producing a large number of highly active hydroxyl radicals (·OH), thereby activating the indirect oxidation pathway.

[0044] High efficiency and synergy: The physical mass transfer enhancement and chemical oxidation activation processes mentioned above occur simultaneously and continuously in the same confined space, achieving a synergistic effect of "1+1>2", thereby significantly improving the overall oxidation and degradation efficiency of recalcitrant organic pollutants.

[0045] Furthermore, the ultrasonic transducer has an ultrasonic frequency of 15 kHz to 1 MHz.

[0046] Furthermore, the pore size of the microporous aerator head is 1~300μm.

[0047] Based on the Minneart bubble resonance frequency formula, the resonance diameter of the bubble is negatively correlated with the ultrasonic frequency. When the ultrasonic frequency is 15 kHz to 1 MHz, the resonance diameter of the bubble is in the range of 1 to 300 μm. The pore size of the corresponding microporous aerator is preferably 1 to 300 μm to ensure that the size of the initial bubble and the ultrasonic frequency form a precise resonance match.

[0048] The ultrasonic frequency range applicable to this invention is 15 kHz to 1 MHz. The wavelength of ultrasound in water depends on the speed of sound, typically taken as 1500 m / s under standard conditions. According to the wavelength formula, the wavelength range in water is between 1.5 and 100 mm. When the cavity size is less than one-quarter of the wavelength of the propagating ultrasound, the pressure gradient of its sound field is small, making the cavitation effect uniform on a spatial scale. Therefore, to obtain a uniform cavitation field, preferably, the inner diameter of the reaction tube is 0.3 to 25 mm.

[0049] Based on the spatial confinement effect of ultrasonic cavitation, the presence of rigid boundaries significantly alters the dynamics of bubble collapse, causing it to occur earlier and more violently, and its morphology to change from symmetrical to asymmetrical. When a bubble collapses near a rigid wall, the symmetry of the surrounding flow field is disrupted. This causes the inward jet generated by the collapse to no longer point towards the bubble center, but rather towards the nearest solid boundary, forming a high-speed microjet. This directional microjet can generate a strong local impact on the wall. In spatially confined areas, the cavitation effect is more controllable, which is beneficial for improving the consistency, stability, and batch repeatability of the degradation effect. Therefore, preferably, a confinement gap ≤ 1.25 mm between the outer wall of the microporous aerator and the inner wall of the reaction tube provides a better confinement effect.

[0050] In this invention, the reaction tube is entirely within the ultrasonic region of the ultrasonic transducer. As the core reaction cavity, to maximize the utilization of ultrasonic energy without clogging the material, the microporous aerator head should occupy as much space as possible within the reaction tube. That is, the length of the microporous aerator head should be less than or equal to the length of the reaction tube's inner cavity. Preferably, the length of the microporous aerator head is equal to the length of the reaction tube's inner cavity. It is easy to understand that the inner cavity of the reaction tube here refers to the space within the reaction tube excluding the space occupied by connections to the preceding and following pipe fittings. This is the core reaction cavity within the reaction tube. Figure 1 As shown. The reaction liquid outlet of the reaction tube can be connected to other pipe fittings to discharge the reacted materials, such as... Figure 1 As shown by the dashed line.

[0051] Furthermore, the reaction tube is a circular straight tube, and the microporous aeration head has a cylindrical shape. The reaction tube and the microporous aeration head are coaxially arranged, forming an annular confining gap between the inner wall of the reaction tube and the outer wall of the microporous aeration head. The confining gap is actually the radial gap between the outer wall of the microporous aeration head and the inner wall of the reaction tube.

[0052] Furthermore, multiple micron-sized pores are evenly distributed on the circumferential side of the microporous aeration head and on the end face of the microporous aeration head away from the air delivery pipe.

[0053] Based on the above-mentioned confined flow ultrasonic-enhanced ozone oxidation microbubble reactor, this invention applies it to the degradation treatment of organic pollutants. Specifically, the reaction liquid containing organic pollutants is continuously fed into the reaction tube, ozone is fed into the microporous aeration head through the gas supply pipe, and ultrasonic treatment is started. By adjusting the ozone dosage, reaction liquid flow rate, ultrasonic power, and reaction time, the organic pollutants are degraded and mineralized.

[0054] Preferably, the present invention also proposes a method for degrading organic pollutants, employing the above-mentioned confined flow ultrasonic-enhanced ozone oxidation microbubble reactor, comprising the following steps: S1. The reaction liquid containing organic pollutants is fed into the reactor from the reaction liquid inlet of the branch pipe in a continuous flow manner, and enters the annular flow channel of the confined gap through the liquid delivery gap; S2. Ozone gas is introduced into the microporous aerator through the gas delivery pipe, and continuously injected into the reaction liquid in the confined gap in the form of micron-sized bubbles through the pores of the microporous aerator. S3. Start the ultrasonic transducer and apply ultrasonic waves into the reaction tube. By adjusting the ozone dosage, reaction liquid flow rate, ultrasonic power and hydraulic residence time, the organic pollutants in the reaction liquid are continuously degraded and mineralized.

[0055] This invention has the following advantages: 1. Achieving active constraint on bubble behavior and efficient acoustic-gas resonance coupling: This invention applies a close physical boundary constraint to the nascent ozone bubbles by constructing an annular confined gap between the outer wall of the microporous aerator head and the inner wall of the reaction tube. This effectively inhibits their free growth, aggregation, and rapid upward escape, stabilizing the bubble size at the micrometer level and enabling precise resonance matching with the ultrasonic frequency. At the same time, the confined space significantly slows down the bubble's rising speed, prolongs the gas-liquid contact and reaction time, and keeps the bubbles continuously in the core region of the ultrasonic cavitation field, greatly improving the bubble capture and collapse efficiency. This fundamentally solves the core bottleneck of low acoustic-gas coupling efficiency in existing technologies.

[0056] 2. Synergistic effect of simultaneous enhancement of physical mass transfer and activation of chemical oxidation pathway: In the confined flow structure of this invention, the enhancement of physical mass transfer and activation of chemical oxidation occur simultaneously and continuously within the same confined space. On the one hand, the residence time of the confined microbubble cluster is extended, and the microjets and violent disturbances generated by ultrasonic cavitation continuously renew the gas-liquid interface, greatly promoting the dissolution and mass transfer of ozone. On the other hand, the confined microbubbles, as ideal cavitation nuclei, continuously undergo violent asymmetric collapse in the ultrasonic field, generating a local extreme high temperature and high pressure environment, which efficiently promotes the decomposition and generation of ozone. Strong oxidizing species such as OH simultaneously enhance the direct and indirect oxidation pathways of ozone, achieving a synergistic effect of "1+1>2".

[0057] 3. Highly simplified structure, low cost, and suitable for continuous flow treatment scenarios: The core components of the reactor in this invention are only an ultrasonic transducer, a reaction tube, a connecting tube, and a microporous aerator head. It does not rely on additional catalysts, ultraviolet light sources, packed beds, or multi-stage treatment units, which significantly reduces system complexity, manufacturing costs, and operation and maintenance difficulties compared to existing technologies. At the same time, the continuous flow channel is constructed through the connecting tube structure of the main pipe and branch pipes, which can realize continuous sampling and treatment of wastewater, without the efficiency bottleneck of intermittent operation, and is suitable for large-scale industrial wastewater treatment scenarios.

[0058] 4. Scientific sound field design ensures a uniform and stable reaction environment with good batch repeatability: The inner diameter of the reaction tube in this invention is acoustically optimized to be less than one-quarter of the wavelength of ultrasound in water, ensuring uniform sound pressure distribution within the tube and stable occurrence of cavitation effect throughout the reaction area. This provides a controllable and consistent reaction environment for microbubble dispersion, ozone dissolution, and free radical generation, effectively improving the stability and batch repeatability of pollutant degradation.

[0059] The technical solution of the present invention will be described in detail below with specific embodiments.

[0060] Example 1 Based on the device of the present invention, this embodiment explores the effect of the confined gap on the performance of ultrasound-enhanced ozone degradation of fumaric acid, which is a characteristic model pollutant of the ozone direct oxidation pathway.

[0061] The experiment was conducted in a fumaric acid solution with an initial concentration of 0.4 mM. The system circulation volume was 100 mL, the solution flow rate was 300 mL / min, the ozone flow rate was 6 mL / min, the ultrasonic power was 35 W, the frequency was 20 kHz, and the pore size of the microporous aerator head was 3 μm (±2 μm). By adjusting the confinement gap to 0.25 mm, 0.75 mm, 1.25 mm, 1.75 mm, 2.25 mm, and 2.75 mm, three parallel samples were set up for each experiment. Samples were taken after 2.5 min of reaction, and the residual concentration of fumaric acid was determined by high performance liquid chromatography (HPLC). The degradation rate was calculated, and the result was the average of the parallel samples.

[0062] The results are as follows Figure 2 As shown, the degradation rate of fumaric acid decreased significantly with increasing confinement gap. The highest degradation rate of 86.2% was achieved with a gap of 0.25 mm, and the degradation rate of 84.8% was achieved with a gap of 1.25 mm. When the gap exceeded 1.25 mm, the degradation rate decreased, and the degradation rate of 2.75 mm gap was only 68.8%.

[0063] Experimental results show that the "confined flow" structure plays a crucial role in the degradation reaction. Traditional reactors lack spatial constraints on bubble behavior, leading to the free growth, coalescence, and escape of ozone bubbles in the ultrasonic field, making it difficult to achieve stable and efficient energy coupling. The device structure of this invention achieves physical constraints on bubble growth and movement. This confined gap structure can effectively control bubble size, making it easier to form micron-sized bubbles that resonate with ultrasonic frequencies (e.g., 20 kHz). These bubbles are then efficiently captured by the ultrasonic field and undergo continuous oscillation, growth, and collapse. At the same time, the confined space significantly slows down the bubble rise velocity, prolongs gas-liquid contact and reaction time, and allows ultrasonic energy to act more concentratedly on the microbubble cluster, enhancing the local cavitation effect, promoting ozone dissolution and the generation of reactive species such as hydroxyl radicals, fundamentally improving mass transfer and reaction efficiency.

[0064] Based on experimental results, the confined gap structure designed in this invention can effectively improve the capture and collapse efficiency of ozone microbubbles in an ultrasonic field, and enhance the ozone mass transfer and free radical reaction pathways. The confined gap has a good effect within a certain range, but further increasing the confined gap will lead to a weakening of the confinement effect, easy bubble aggregation and escape, and a decrease in synergistic effect.

[0065] Example 2 Based on the device of the present invention, this embodiment explores the effect of the confined gap on the ultrasonic-enhanced ozone indirect oxidation pathway, and selects terephthalic acid as the hydroxyl radical ( The characteristic probe molecule of OH has extremely low direct reactivity with ozone molecules, and its degradation rate can specifically reflect the state of ozone in the system. The strength of OH formation.

[0066] An initial 0.4 mM terephthalic acid solution was used. The system circulation volume was 100 mL, the solution flow rate was 300 mL / min, the ozone flow rate was 6 mL / min, the ultrasonic power was 35 W, the operating frequency was 20 kHz, and the aeration head pore size was 3 μm (±2 μm). Six groups of confinement gaps of 0.25 mm, 0.75 mm, 1.25 mm, 1.75 mm, 2.25 mm, and 2.75 mm were set up, with three parallel samples for each group. Samples were taken after 5 min of reaction, and the residual concentration of terephthalic acid was measured using a UV spectrophotometer. The degradation rate was calculated, and the result was the average of the parallel samples.

[0067] The results are as follows Figure 3 As shown, the degradation rate of terephthalic acid gradually decreases with the increase of the confinement gap. The highest degradation rate of 23.5% is reached at a gap of 0.25 mm, and the degradation rate of 22.3% is reached at a gap of 1.25 mm. When the gap exceeds 1.25 mm, the degradation rate decreases significantly, and the degradation rate of 2.75 mm gap is only 7.7%.

[0068] The experimental results demonstrate that the narrow confined structure not only restricts bubble growth, making it more susceptible to capture and collapse by ultrasonic resonance, but also enhances the local high temperature and pressure and hydraulic shearing effects induced by cavitation, thereby significantly promoting the conversion of ozone to ·OH. The experimental results directly confirm that the "confined" design, by regulating microbubble behavior, can effectively enhance the indirect oxidation pathway of ozone, improve the efficiency of free radical attack on recalcitrant organic matter, and further highlight the unique advantages of this invention in enhancing advanced oxidation processes.

[0069] Example 3 Based on the device of the present invention, this embodiment investigates the effect of confined gaps on the ultrasonic-assisted ozone degradation performance, using Rhodamine B (RhB) as a typical recalcitrant dye pollutant.

[0070] The initial concentration of Rhodamine B was 1 mM, the system circulation volume was 100 mL, the ozone flow rate was 6 mL / min, the solution circulation rate was 300 mL / min, the ultrasonic power was 35 W, the ultrasonic frequency was 20 kHz, and the pore size of the aeration head was 3 μm (±2 μm). Tests were conducted at confinement gaps of 0.25 mm, 0.75 mm, 1.25 mm, 1.75 mm, 2.25 mm, and 2.75 mm. Three parallel samples were set up for each experiment. Samples were taken after 5 min of reaction, and the residual concentration of Rhodamine B was determined using a UV spectrophotometer. The degradation rate was calculated, and the average value of the parallel samples was taken as the result.

[0071] The results are as follows Figure 4 As shown, the degradation efficiency of Rhodamine B continuously decreases with the increase of the confinement gap. The highest degradation rate of 68.2% is reached at a gap of 0.25 mm, and the degradation rate of 66.8% is reached at a gap of 1.25 mm. When the gap exceeds 1.25 mm, the degradation rate decreases significantly, and the degradation rate of 48.8% is reached at a gap of 2.75 mm.

[0072] Rhodamine B has a stable molecular structure and high color intensity, and its degradation is often slow during ozone oxidation alone due to mass transfer limitations. In this example, we observed that the degradation efficiency of Rhodamine B varies with the confined space, which can be analyzed from the perspective of the coupling mechanism between microbubble behavior and ultrasonic cavitation.

[0073] When the confinement gap is narrow, such as ≤1.25 mm, ozone bubbles are tightly confined within the narrow channel. Their size makes them more susceptible to resonance with 20 kHz ultrasound, leading to efficient capture by the cavitation field and subsequent continuous oscillation and collapse. This process not only significantly increases the contact area between ozone and pollutants but also promotes ozone decomposition and the generation of hydroxyl radicals through the localized high-temperature and high-pressure environment during cavitation collapse, thereby achieving efficient decolorization and degradation of Rhodamine B. Furthermore, the strong turbulence formed within the confined space further enhances the mass transfer and mixing processes. As the confinement gap increases further, the bubble size increases, its degrees of freedom of motion increase, its resonant coupling with the ultrasonic field weakens, and the cavitation intensity decreases. Consequently, the efficiency of ozone mass transfer and free radical generation both decrease, resulting in a significant reduction in the Rhodamine B degradation rate. The results of this embodiment demonstrate that optimizing the confinement gap can achieve efficient synergy in the ultrasound-microbubble-ozone system, providing a compact and effective technical solution for treating recalcitrant dye wastewater.

[0074] Example 4 This embodiment explores the mechanism of ultrasound-enhanced ozone dissolution and conversion.

[0075] Ultrasonic cavitation can enhance the dissolution process of gases in liquids. To verify this effect, an experiment was first conducted to enhance oxygen dispersion and dissolution using ultrasound. This experiment aimed to observe whether the dissolution rate and equilibrium concentration of oxygen in water could be effectively increased under ultrasonic treatment, thus providing direct experimental evidence for subsequent research on the dissolution and conversion mechanisms of ozone. A JPB-607A portable dissolved oxygen meter was used to detect the dissolved oxygen concentration (mg / L) in water in real time based on its electrochemical sensing principle. By comparing the changes in dissolved oxygen under the same aeration conditions with and without ultrasonic treatment, the promoting effect of ultrasound on gas mass transfer and dissolution can be reflected.

[0076] The experimental procedure is as follows: Using the device of this invention, the aeration head has an pore size of 3 μm (±2 μm), and the ultrasonic transducer operates at a frequency of 20 kHz. Deionized water is used as the medium, maintaining a circulation volume of 100 mL and a solution flow rate of 200 mL / min. Oxygen is introduced at flow rates of 2, 4, and 6 mL / min under a constant temperature of 20℃. The results are compared between ultrasonic treatment with and without ultrasonic treatment (0 W). Three parallel samples are set up for each experiment. After 10 min of continuous treatment, the dissolved oxygen concentration in the water is measured using a JPB-607A portable dissolved oxygen meter. The average value of the parallel samples is taken.

[0077] The results are as follows Figure 5 As shown, without ultrasound, the dissolved oxygen concentration only increases slowly with increasing oxygen flow rate, with concentrations of 12.7, 13.5, and 16.0 mg / L at flow rates of 2, 4, and 6 mL / min, respectively. After ultrasound is turned on, the dissolved oxygen concentrations at all flow rates increase significantly, reaching 19.3, 20.2, and 21.6 mg / L, respectively, which directly confirms the significant enhancing effect of ultrasonic cavitation on gas dissolution and mass transfer.

[0078] After clarifying the promoting effect of ultrasound on oxygen dissolution, the research subject was changed to ozone. As a strong oxidant, the actual effect of ozone in water treatment largely depends on its dissolution efficiency and subsequent decomposition and transformation pathways. Ultraviolet spectroscopy was used to observe the changes in the dissolved state of ozone in water and its decomposition behavior under ultrasound.

[0079] Ozone molecules exhibit characteristic ultraviolet absorption at a wavelength of 260 nm, and the absorption intensity directly reflects the concentration of dissolved ozone in the solution. Meanwhile, ozone decomposition products in water, such as hydrogen peroxide, show an absorption peak around 190 nm. By simultaneously monitoring the absorption changes in these two wavelength bands, it is possible to distinguish whether ultrasound merely increases the physical solubility of ozone or further promotes its chemical decomposition.

[0080] The experimental procedure is as follows: Using the device of this invention, the system was kept in a continuous flow state. Ozone gas was injected into the system at a constant flow rate of 6 mL / min through the microporous aerator, maintaining a solution flow rate of 200 mL / min, a circulation volume of 100 mL, and an ambient temperature controlled at 20℃. Two parallel experiments were conducted: one without ultrasound and the other with 35 W of ultrasound power applied. Each experiment had three parallel samples. After running for 5 minutes, samples were taken, and a UV spectrophotometer was used to rapidly scan the samples in the wavelength range of 190-300 nm.

[0081] The results are as follows Figure 6 As shown, without ultrasound, the solution exhibits a distinct absorption peak at 260 nm, indicating that ozone is stably dissolved in molecular form; while only weak background absorption is observed in the 190 nm region. After ultrasound treatment, the situation changes significantly: the absorption peak at 260 nm weakens significantly, while the absorption intensity at 190 nm increases simultaneously.

[0082] This trend indicates that the effects of ultrasonic cavitation extend far beyond simply promoting gas dissolution: on the one hand, it accelerates the transfer of ozone from the gas phase to the liquid phase through microscopic mechanical disturbances and interfacial renewal; on the other hand, the high-energy environment generated by cavitation provides energy for the decomposition of ozone molecules, enabling them to be converted more efficiently into more oxidizing intermediates. This result reveals the key to the synergistic effect of ultrasound and ozone at the mechanistic level—not only improving the mass transfer efficiency of ozone but also activating its oxidation potential, creating more favorable conditions for the subsequent degradation of organic pollutants.

[0083] Example 5 To more directly evaluate the actual enhancing effect of ultrasound on the ozone oxidation process, this embodiment uses fumaric acid as a model pollutant for degradation experiments. Fumaric acid (trans-succinic acid) is characterized by its ability to undergo a direct and rapid selective oxidation reaction with ozone molecules. This means that if the effect of ultrasound is mainly manifested at the physical level, such as improving ozone dispersion, increasing the gas-liquid contact area, or prolonging the residence time, then the introduction of ultrasound should significantly enhance the degradation rate of fumaric acid, because more ozone molecules can more effectively contact the target pollutant.

[0084] A 0.4 mM fumaric acid aqueous solution was prepared as the treatment target. The experiment was conducted in a continuous flow reaction system, and the process was as follows: the total circulation volume of the system was 100 mL, and the solution was circulated at a flow rate of 300 mL / min using a peristaltic pump. Ozone was injected at a constant flow rate of 6 mL / min through a microporous aerator. For comparison, four sets of experimental conditions were set up: ultrasound alone (35 W, no ozone), ozone alone (6 mL / min, no ultrasound), ultrasound and ozone combined (35 W + 6 mL / min), and a blank control (no ultrasound, no ozone). Each experiment had three parallel samples. Samples were taken after 2.5 min of reaction, and the residual concentration of fumaric acid was determined by HPLC. The degradation rate was calculated, and the result was the average of the parallel samples.

[0085] The results are as follows Figure 7 As shown, the degradation rate of fumaric acid in the ultrasound-only group was only 1.4%, with almost no degradation effect; the degradation rate in the ozone-only group was 59.8%; and the degradation rate in the ultrasound-ozone combined group jumped to 86.2%, which was significantly higher than the sum of the degradation rates of the ultrasound-only and ozone-only groups, directly proving that ultrasound can significantly enhance the direct oxidation pathway of ozone and greatly improve the utilization efficiency of ozone.

[0086] This embodiment strongly confirms the following inference: ultrasound is not merely an independent degradation force. More importantly, through the microjets and intense disturbances generated by its cavitation effect, it greatly optimizes the distribution of ozone bubbles in water, breaking large bubbles into micron- or even submicron-scale bubble clouds, thereby significantly increasing the collision frequency and reaction probability between ozone and fumaric acid molecules. In other words, ultrasound enhances the direct oxidation pathway of ozone.

[0087] Example 6 This embodiment uses terephthalic acid as a probe molecule to investigate whether ultrasound can excite and enhance the indirect oxidation of ozone, i.e., promote the generation of hydroxyl radicals. Unlike fumaric acid, terephthalic acid hardly reacts directly with ozone molecules, but the benzene ring in its molecular structure is easily attacked by hydroxyl radicals, generating 2-hydroxyterephthalic acid with characteristic fluorescence. Therefore, this molecule is often used as an "indicator" of hydroxyl radical generation in water. If the introduction of ultrasound can significantly increase the degradation rate of terephthalic acid, it can directly prove that ultrasonic cavitation effectively promotes the process of ozone decomposition and the generation of hydroxyl radicals.

[0088] The experimental procedure was as follows: A 0.4 mM aqueous solution of terephthalic acid was prepared as the treatment target. The system circulation volume was 100 mL, and the solution flow rate was controlled at 300 mL / min. Ozone gas was continuously introduced at a flow rate of 6 mL / min. Three control experiments were also set up: ultrasound alone (35 W), ozone alone (6 mL / min), and ultrasound-ozone combined (35 W + 6 mL / min). In a reaction environment at a constant temperature of 20℃, three parallel samples were set up for each experiment. Samples were taken after 5 min of reaction, and the residual concentration of terephthalic acid was measured using a UV spectrophotometer. The degradation rate was calculated, and the result was the average value of the parallel samples.

[0089] The results are as follows Figure 8 As shown, the degradation rate of terephthalic acid in the ultrasound-only group was only 0.4%, almost no degradation effect; the degradation rate in the ozone-only group was only 2.9%, confirming the extremely low direct reaction activity between terephthalic acid and ozone molecules; the degradation rate in the ultrasound-ozone combined group jumped to 23.5%, far exceeding the sum of the two individual treatments, directly proving that ultrasonic cavitation can efficiently promote ozone decomposition and generation. OH significantly activates and enhances the indirect oxidation pathway of ozone.

[0090] This embodiment clearly reveals another key role of ultrasound in the ozone oxidation system: ultrasound treatment is not only an enhancer of physical mass transfer, but also an "activator" of chemical reactions. The localized extreme high temperature and pressure conditions generated by ultrasonic cavitation, and the resulting intense hydraulic shearing and water molecule fragmentation, provide ozone molecules with an additional energy pathway, making them easier to decompose and generate a large number of highly reactive hydroxyl radicals. This embodiment directly confirms, through the significant change in the degradation rate of terephthalic acid, that the ultrasound-ozone synergistic system can efficiently initiate and enhance the radical-based indirect oxidation pathway, providing a crucial mechanistic basis for treating persistent organic compounds that are more difficult to degrade through direct oxidation.

[0091] Example 7 This embodiment verifies the effectiveness of the device with built-in microporous aerator heads in actual wastewater treatment. Rhodamine B was selected as the target pollutant, and the synergistic degradation performance of ozone and ultrasound under "with aerator heads" and "without aerator heads" conditions was compared systematically to clarify the specific contribution of micron-sized bubbles to enhancing mass transfer and reaction processes.

[0092] Based on the device of this invention, to simulate the effect of traditional coarse aeration and provide a comparison, two ozone introduction methods were set up: one is to inject ozone through an aeration head with a built-in pore precision of 12μm (±2μm); the other is to remove the aeration head and directly introduce ozone through the same air supply pipe, in which case the bubble size is larger (usually in the millimeter range). Rhodamine B aqueous solution with the same initial concentration was prepared as simulated wastewater, the system circulation volume was 100 mL, and the solution flow rate was set to 100 mL / min. Ozone was introduced at a flow rate of 6 mL / min. Three sets of conditions were compared: ozone alone without an aeration head, ozone alone with an aeration head, and ozone combined with ultrasound (45 W) with an aeration head. All experiments were conducted at a constant temperature of 20℃, with three parallel samples in each group. Samples were taken after 5 min of reaction, the residual concentration of Rhodamine B was measured, the degradation rate was calculated, and the result was the average of the parallel samples.

[0093] The results are as follows Figure 9 As shown, without an aeration head, the degradation rate of Rhodamine B was low, at only 9.8%. This indicates that in the absence of micron-sized bubbles as an effective mass transfer carrier and cavitation nucleus, ultrasonic energy is difficult to couple effectively with ozone, resulting in a weak synergistic effect. However, the situation changed dramatically after installing a microporous aeration head. The degradation rate of the "aeration head + ozone" group alone was significantly higher than that of the corresponding group without an aeration head, reaching 45.6%. This directly demonstrates the improvement in ozone mass transfer efficiency brought about by micron-sized bubbles themselves. When ultrasound was applied on this basis, i.e., in the "aeration head + ozone + ultrasound" group, the degradation rate of Rhodamine B jumped to near-complete removal in a very short time, reaching 68.2%, with significantly accelerated degradation kinetics, far exceeding all other control groups.

[0094] This stark contrast clearly reveals that the microporous aerator is not merely a simple gas distribution device, but a crucial hub for achieving efficient synergy between ultrasound and ozone. The microporous aerator converts ozone into micron-sized bubbles that match the size of the ultrasonic cavitation field. These microbubbles serve as excellent carriers for ozone mass transfer and also as effective gas nuclei for ultrasonic cavitation, thus greatly promoting the dissolution, dispersion, and free radical conversion of ozone during cavitation collapse. This embodiment not only demonstrates the device's high efficiency in treating recalcitrant dye wastewater but also highlights the core value of the precise coupling between "microbubble generation" and "ultrasonic cavitation field" through a direct comparison with and without the aerator.

[0095] According to Examples 1-7, the present invention has the following advantages: The device of this invention achieves active constraint on bubble behavior and efficient acoustic-gas coupling. By constructing an annular confinement gap between the outer wall of the microporous aerator and the inner wall of the reaction tube, the confinement gap can be varied according to requirements, imposing immediate physical boundary constraints on nascent ozone bubbles, effectively inhibiting their free growth, aggregation, and rapid escape. The bubble size can be stably controlled at the micrometer level, easily achieving resonance matching with ultrasonic frequencies (e.g., 20 kHz), causing their collapse to occur earlier and more violently, significantly enhancing the ozone dissolution and mass transfer process.

[0096] This invention features a highly simplified structure, offering advantages in both high integration and low cost. It eliminates the need for additional catalysts, ultraviolet light sources, packed beds, or multi-stage processing units. Compared to existing technologies that often require the coupling of complex processes such as photocatalysis, micro-electrolysis, and biological treatment, this invention significantly reduces system complexity, manufacturing costs, and maintenance difficulty, making it more suitable for large-scale application and promotion.

[0097] In this invention, the cavitation effect is locally enhanced within a confined space, significantly improving synergistic oxidation efficiency. Microbubble clusters, acting as ozone carriers and cavitation nuclei, are confined to a high-intensity, uniformly distributed ultrasonic cavitation field core region, continuously undergoing oscillation, growth, and violent asymmetric collapse. This process simultaneously achieves physical enhancement of ozone dissolution mass transfer and accelerates ozone decomposition into strong oxidizing species such as ·OH through local extreme conditions generated by cavitation collapse (e.g., high temperature, high pressure, microjets), realizing highly efficient synergy between enhanced physical mass transfer and activation of the chemical oxidation pathway.

[0098] The device of this invention features a scientifically designed acoustic field, resulting in a uniform and stable reaction environment. The inner diameter of the reaction tube is acoustically optimized to be less than one-quarter of the wavelength of ultrasound in the medium, ensuring uniform sound pressure distribution and stable cavitation effects throughout the reaction region. This provides a controllable, efficient, and consistent reaction environment for the full dispersion of microbubbles, the dissolution of ozone, and the generation of free radicals, which is beneficial for the stability and repeatability of the degradation process.

[0099] The embodiments provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention, and the descriptions of the embodiments above are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A confined flow ultrasonic-enhanced ozone oxidation microbubble reactor, characterized in that, include: Ultrasonic components; The delivery assembly includes a reaction tube (2) and a connecting tube (3). The outer wall of the reaction tube (2) is tightly coupled to the ultrasonic component. The ultrasonic component transmits sound waves to the liquid phase inside the reaction tube (2). One end of the reaction tube (2) serves as the outlet of the reaction liquid, and the other end of the reaction tube (2) serves as the interface. The connecting tube (3) includes a main tube (31) and a branch tube (32). The branch tube (32) is located on the side of the main tube (31). One end of the branch tube (32) serves as the inlet of the reaction liquid. One end of the main tube (31) is connected to the interface of the reaction tube (2), and the other end of the main tube (31) is closed. The ozone assembly includes a gas delivery pipe (4) and a microporous aeration head (5). The microporous aeration head (5) is installed inside the reaction tube (2). The gas delivery pipe (4) is installed inside the main pipe (31) of the connecting pipe (3). One end of the gas delivery pipe (4) is connected to the microporous aeration head (5), and the other end of the gas delivery pipe (4) extends out from the closed end of the main pipe (31). There is a liquid delivery gap (7) between the outer wall of the gas delivery pipe (4) and the inner wall of the main pipe (31). There is a confinement gap (6) between the microporous aeration head (5) and the inner wall of the reaction tube (2). The liquid delivery gap is connected to the confinement gap through the interface of the reaction tube to form a flow channel for continuous flow of reaction liquid.

2. The confined flow ultrasonic-enhanced ozone oxidation microbubble reactor according to claim 1, characterized in that, The confinement gap (6) is ≤1.25 mm.

3. The confined flow ultrasonic-enhanced ozone oxidation microbubble reactor according to claim 1, characterized in that, The pore size on the microporous aeration head (5) is 1~300μm.

4. The confined flow ultrasonic-enhanced ozone oxidation microbubble reactor according to claim 3, characterized in that, The ultrasonic frequency of the ultrasonic transducer (1) is 15 kHz to 1 MHz.

5. The confined flow ultrasonic-enhanced ozone oxidation microbubble reactor according to any one of claims 1-4, characterized in that, The reaction tube (2) is a circular straight tube, and the microporous aeration head (5) is cylindrical in shape. The reaction tube (2) and the microporous aeration head (5) are coaxially arranged, forming an annular confinement gap (6) between the inner wall of the reaction tube (2) and the outer wall of the microporous aeration head (5).

6. The confined flow ultrasonic-enhanced ozone oxidation microbubble reactor according to claim 5, characterized in that, The inner diameter of the reaction tube (2) is 0.3~25 mm.

7. The confined flow ultrasonic-enhanced ozone oxidation microbubble reactor according to claim 1, characterized in that, Multiple micron-sized pores are evenly distributed on the circumferential side of the microporous aeration head (5) and the end face of the microporous aeration head (5) away from the air supply pipe (4).

8. An application of a confined flow ultrasonic-enhanced ozone oxidation microbubble reactor, characterized in that, This includes the application of the confined flow ultrasonic-enhanced ozone oxidation microbubble reactor as described in any one of claims 1-7 in the continuous flow treatment of wastewater for degrading organic pollutants.

9. The application according to claim 8, characterized in that, The method for degrading organic pollutants using the above-mentioned confined flow ultrasonic-enhanced ozone oxidation microbubble reactor includes the following steps: S1. The reaction liquid containing organic pollutants is fed into the reactor from the reaction liquid inlet of the branch pipe in a continuous flow manner, and enters the flow channel of the confined gap through the liquid delivery gap; S2. Ozone gas is introduced into the microporous aerator through the gas delivery pipe, and continuously injected into the reaction liquid in the confined gap in the form of micron-sized bubbles through the pores of the microporous aerator. S3. Activate the ultrasonic component to apply ultrasonic waves into the reaction tube. By adjusting the ozone dosage, reaction liquid flow rate, ultrasonic power, and hydraulic residence time, the organic pollutants in the reaction liquid are continuously degraded and mineralized.

Images