Rapid purification device for mariculture tail water

Abstract

The invention discloses a rapid purification device for mariculture tail water. The rapid purification device comprises a pretreatment unit, an atomization catalytic reaction unit and a membrane separation unit which are connected in sequence. The atomization catalytic reaction unit atomizes a hydrogen peroxide solution into tiny liquid drops through an ultrasonic atomization system, the tiny liquid drops and ozone form oxidizing mixed gas in a mixing and conveying assembly, and the oxidizing mixed gas is released to a reaction chamber through an aeration structure; a detachable suspended catalytic structure is arranged in the reaction chamber, the core of a core-shell catalyst particle is magnetic Fe3O4, the shell of the core-shell catalyst particle is a TiO2-ZrO2 composite oxide, and the core-shell catalyst particle is loaded on a mesh bag type carrier assembly. According to the device, mass transfer is enhanced through ultrasonic atomization, pollutants are efficiently degraded through the core-shell catalyst, the modular structural design is convenient to maintain, the COD and ammonia nitrogen removal rate is high, the ozone utilization rate is increased, the device is remarkably superior to a traditional treatment device, and the device is suitable for rapid purification treatment of large-scale mariculture tail water.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and particularly proposes a rapid purification device for seawater aquaculture tail water. Background Art

[0002] Currently, marine aquaculture tailwater is rich in pollutants such as ammonia nitrogen, organic matter, antibiotics, and suspended solids. If discharged directly without effective treatment, it can easily lead to problems such as eutrophication and ecological imbalance. Existing treatment devices mostly use physical filtration, biological treatment, and chemical oxidation technologies, but these all have significant drawbacks in practical application.

[0003] In terms of physical filtration and biological treatment, traditional devices such as coarse filters and sedimentation tanks can only remove large suspended solids and have limited capacity for treating dissolved pollutants. Biological treatment equipment such as biofilters and activated sludge processes, due to the high salinity of seawater, inhibits microbial activity, resulting in long treatment cycles and low efficiency, making it difficult to meet the demand for rapid tailwater purification. For example, at a salinity of 35‰, the ammonia nitrogen removal efficiency of conventional biofilters is over 40% lower than that of freshwater environments, making it impossible to consistently achieve standard discharge.

[0004] In chemical oxidation technology, although the ozone-hydrogen peroxide combined treatment process can degrade pollutants by generating strong oxidizing free radicals, existing devices generally have the problem of low mass transfer efficiency. Most equipment uses the method of directly adding reagents, which leads to insufficient mixing of ozone and hydrogen peroxide, small gas-liquid contact area, and limited free radical production. At the same time, the catalyst loading method is unreasonable. Some devices use powdered catalysts, which are easy to lose and difficult to recover. In devices using fixed bed loading, the catalyst is not in sufficient contact with the reaction fluid, the utilization rate of active sites is low, and it is difficult to fully exert the catalytic efficiency. In addition, the structural design of the existing device does not take into account the strong corrosiveness and high salt environment of seawater, and the layout of the catalytic structure and aeration structure is unreasonable, resulting in low ozone utilization and high operating costs.

[0005] In terms of overall structural design, the existing treatment units are relatively independent and lack synergy, making it impossible to achieve efficient and continuous treatment of marine aquaculture tailwater. For example, the pretreatment unit and the chemical oxidation unit are poorly connected, resulting in large fluctuations in the tailwater quality entering the oxidation unit, affecting the treatment effect. The membrane separation unit is not well-matched with other units, making the membrane components easily clogged by contaminants and having a short service life.

[0006] In summary, existing marine aquaculture tailwater treatment devices have shortcomings in mass transfer efficiency, catalytic performance, and structural design, making it difficult to rapidly purify complex marine aquaculture tailwater. There is an urgent need to develop a new purification device that can enhance gas-liquid mass transfer, improve catalytic efficiency, and optimize structural design to address these technical challenges. Summary of the Invention

[0007] In view of this, the present invention proposes a rapid purification device for marine aquaculture tail water. Through innovative ultrasonic atomization mass transfer enhancement, high-efficiency catalysis of core-shell structure catalysts, and modular unit collaborative design, it solves the problems of low mass transfer efficiency, poor catalyst activity, and insufficient coordination of treatment processes in existing devices, and realizes efficient, rapid, and stable purification of marine aquaculture tail water to meet the needs of meeting discharge standards or reuse.

[0008] The technical solution of the present invention is achieved as follows: The present invention provides a rapid purification device for seawater aquaculture tail water, comprising a pretreatment unit, an atomization catalytic reaction unit and a membrane separation unit connected in sequence.

[0009] The pretreatment unit consists of a coarse filter and a flocculation flotation tank, which are interconnected. The coarse filter uses a stainless steel mesh with a pore size of 0.1-1mm. It removes large suspended solids, leftover bait, and aquaculture waste from the seawater through mechanical interception, reducing the load on subsequent treatment units. The flocculation flotation tank is equipped with a coagulant dosing device and a dissolved air pump. By adding coagulants such as polyaluminum chloride, colloids and tiny suspended particles in the water are agglomerated into larger flocs. The dissolved air pump produces dissolved air water, in which supersaturated air is released as tiny bubbles. These bubbles adhere to the flocs and, due to buoyancy, are brought to the surface, forming scum. This is removed by scraping equipment, further reducing the turbidity and organic content of the tailwater. The turbidity of the pretreated tailwater can be reduced by 60%-80%.

[0010] Atomization catalytic reaction unit: Ultrasonic atomization system: This system includes a hydrogen peroxide storage tank and an ultrasonic atomizer. The ultrasonic atomizer utilizes high-frequency vibration, operating at a frequency of 40-60 kHz, to atomize the hydrogen peroxide solution in the tank into tiny droplets with a particle size of 1-10 μm. Compared to traditional pressure atomization, ultrasonic atomization produces smaller and more evenly distributed droplets, significantly increasing the gas-liquid contact area and boosting mass transfer efficiency by 3-5 times. This allows hydrogen peroxide and ozone to react more quickly and fully to generate highly oxidizing free radicals.

[0011] The gas mixing and delivery assembly consists of an ozone generator and a motive gas delivery pipeline. The motive gas delivery pipeline features a specially designed mixing chamber equipped with spiral guide plates and a flow disturbance element, which ensures that ozone generated by the ozone generator and ultrasonically atomized hydrogen peroxide droplets are thoroughly mixed within the mixing chamber. Air is used as the motive gas, and the mixed oxidizing gas is delivered to the reaction chamber at a flow rate of 0.5-1 m / s. This ensures that the gas does not separate during delivery and enters the reaction chamber in the appropriate bubble form to participate in the reaction.

[0012] Reaction chamber: A catalytic structure is installed inside, and an aeration structure is installed at the bottom. The aeration structure is connected to the gas mixing and delivery assembly and utilizes a porous ceramic aeration head with a pore size of 0.1-0.3mm. This allows the oxidizing mixed gas to be evenly released into the reaction chamber in the form of tiny bubbles, increasing the contact time between the gas and the tail water. The catalytic structure comprises catalyst particles and a carrier assembly. The catalyst particles have a core-shell structure, with the core being magnetic Fe3O4, prepared by a co-precipitation method, exhibiting excellent magnetic properties and facilitating subsequent recovery. The outer shell is a TiO2@ZrO2 composite oxide, prepared by a sol-gel method with a molar ratio of TiO2 to ZrO2 of 1:1. This composite shell exhibits excellent chemical stability and catalytic activity, effectively accelerating ozone decomposition and the synergistic reaction of H2O2 and ozone. Compared to a single catalyst, the free radical yield is increased by 2.5 times. The carrier assembly comprises a cubic frame structure constructed from corrosion-resistant titanium alloy and multiple load cells mounted on it. The frame surface is equipped with flow channels at an angle of 15°-30° to the horizontal, guiding water and air bubbles evenly through the catalyst particles and enhancing mass transfer. The load cells are mesh bags woven from titanium alloy wire with a mesh size of 0.5-1mm. These are secured to the frame structure via snap-fits, facilitating the loading and replacement of catalyst particles. The catalytic structure is removably suspended within the reaction chamber via a suspension device. The suspension device comprises a support arm connected to the top of the reaction chamber and a removable connector connecting the support arm to the frame structure. The threaded connection facilitates quick disassembly and installation for maintenance and overhaul.

[0013] The reaction chamber structure design adopts a cylindrical structure with a detachable inspection cover on the top to facilitate the inspection, maintenance and replacement of catalyst particles of the catalytic structure; the side is provided with a tail water inlet and a post-reaction water outlet, and the bottom is provided with a sludge discharge port to regularly discharge the sludge generated during the reaction process, ensuring the cleanliness of the interior of the reaction chamber and maintaining stable operation of the device.

[0014] Membrane separation unit: A hollow fiber ultrafiltration membrane module utilizes cross-flow filtration. The ultrafiltration membrane is made of polyvinylidene fluoride (PVDF) with a pore size of 0.01-0.1 μm, exhibiting excellent chemical stability and anti-fouling properties. The membrane separation unit is equipped with a backwash system that combines water backwashing at a pressure of 0.3-0.5 MPa with ultrasonic cleaning at a frequency of 40 kHz. Water backwashing removes larger particulate contaminants from the membrane surface, while ultrasonic cleaning effectively disrupts the binding force between contaminants and the membrane material within the membrane pores, preventing membrane fouling, maintaining a high membrane flux, and extending the membrane's service life.

[0015] How it works Marine aquaculture tailwater first flows into the pretreatment unit, where a coarse filter intercepts large suspended solids. The tailwater then enters the flocculation and flotation tank. In this tank, a coagulant dosing device adds coagulant, agglomerating colloids and tiny suspended particles in the water. The dissolved air pump releases tiny bubbles in the dissolved air, which floats and removes the agglomerated impurities, completing the initial purification process.

[0016] The tail water after preliminary treatment enters the atomization catalytic reaction unit from the tail water inlet of the reaction chamber. The ultrasonic atomizer atomizes the hydrogen peroxide solution into tiny droplets, which are fully mixed with the ozone generated by the ozone generator in the mixing chamber of the power gas delivery pipeline to form an oxidizing mixed gas. The mixed gas is released into the reaction chamber in the form of tiny bubbles through the aeration structure, and is fully in contact with the catalytic structure suspended in the reaction chamber during the rising process. The core-shell structure of the catalyst particles accelerates the decomposition of ozone and the synergistic reaction of H2O2 and ozone, generating a large number of strong oxidizing free radicals, which quickly oxidize and degrade pollutants such as ammonia nitrogen, nitrite, and organic matter in the tail water. The reacted tail water flows out from the post-reaction water outlet and enters the membrane separation unit.

[0017] In the membrane separation unit, cross-flow filtration forces tailwater to flow under pressure along the surface of the ultrafiltration membrane. Small molecules and water pass through the membrane into the product water side, while large organic molecules, microorganisms, and suspended solids are retained, achieving deep purification of the tailwater. A backwash system regularly cleans the ultrafiltration membrane to ensure separation effectiveness, ensuring that the purified tailwater meets discharge standards or is reused.

[0018] The present invention has the following beneficial effects compared to the prior art: The ultrasonic atomization system significantly improves gas-liquid mass transfer efficiency. Combined with highly active core-shell catalyst particles, it significantly increases free radical yield, achieving COD removal rates exceeding 90% and ammonia nitrogen removal rates exceeding 95%. The pretreatment unit and membrane separation unit work synergistically to further ensure comprehensive water quality compliance. The magnetic core of the core-shell catalyst particles facilitates rapid recovery via magnetic separation, while the composite oxide shell exhibits strong catalytic activity and resistance to salt corrosion. After 1000 hours of continuous operation in seawater at a salinity of 35‰, the catalytic activity decreased by only 5%, significantly outperforming conventional catalysts. The layout of the catalytic and aeration structures within the reaction chamber, combined with the frame-structured flow channels, ensures a uniform gas-liquid flow field, increasing ozone utilization by 35% compared to conventional units. The modular carrier assembly and removable suspension facilitate catalyst replacement and maintenance, reducing labor costs. The membrane separation unit's cross-flow filtration and combined backwash technology effectively prevent membrane fouling, extending the service life of the ultrafiltration membrane to 3-5 years. The pretreatment unit reduces influent pollutant concentrations, alleviating the load on subsequent units and ensuring long-term stable operation of the entire unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a schematic plan view of the rapid purification device for seawater aquaculture tail water of the present invention; Figure 2 It is a schematic plan view of part of the structure of the atomization catalytic reaction unit in the rapid purification device for seawater aquaculture tail water of the present invention.

[0021] In the figure: 1-pretreatment unit, 2-atomization catalytic reaction unit, 3-membrane separation unit, 11-coarse filter, 12-flocculation flotation tank, 21-ultrasonic atomization system, 22-gas mixing and conveying component, 23-reaction chamber, 24-catalytic structure, 25-aeration structure, 211-hydrogen peroxide storage tank, 212-ultrasonic atomizer, 221-ozone generator, 222-power gas delivery pipeline, 241-catalyst particles, 242-carrier assembly, 2421-frame structure, 2422-load unit, 243-suspension device, 2431-support arm, 2432-detachable connector, 31-hollow fiber ultrafiltration membrane assembly. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0024] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of the present invention belong. If the definitions set forth in this section are contrary to or otherwise inconsistent with definitions set forth in the patents, patent applications, published patent applications, and other publications incorporated herein by reference, the definitions listed in this section take precedence over the definitions incorporated herein by reference.

[0026] Unless otherwise specified, the methods used in the following examples are conventional methods. The materials, reagents, and instruments used are conventional materials, reagents, and instruments in the art, unless otherwise specified, and can be obtained commercially by those skilled in the art.

[0027] When an amount, concentration or other value or parameter is expressed as a range, a preferred range or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is disclosed alone. For example, when a range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within the range. In the present specification and claims, range definitions may be combined and / or interchanged, and if not otherwise stated, such ranges include all subranges contained therein.

[0028] Example 1 Catalyst particle preparation: Core preparation Materials Preparation: Ferric chloride hexahydrate and ferrous chloride tetrahydrate are used as the iron source. Ammonia is used as the precipitant at a concentration of 25%. Deionized water is also available for solution preparation and subsequent cleaning steps.

[0029] Coprecipitation reaction: According to the molar ratio of Fe 3+ :Fe 2+ = 2:1. Accurately weigh a certain amount of ferric chloride hexahydrate and ferrous chloride tetrahydrate and dissolve them in deionized water to prepare a mixed solution with a total iron ion concentration of 0.5 mol / L. While stirring, slowly add this mixed solution dropwise at a rate of 2 mL / min to a reaction vessel containing excess ammonia (25%). During the addition, maintain the reaction system temperature at 65°C and stir continuously at 500 rpm to ensure sufficient reaction progress. This generates the Fe₃O₄ precursor.

[0030] Product Isolation and Cleaning: After the reaction is complete, magnetic separation technology is used to rapidly separate the resulting Fe3O4 magnetic particles from the reaction mixture using a strong magnet. The separated particles are then washed multiple times with deionized water until the pH of the washing solution reaches approximately 7 to remove impurity ions adsorbed on the particle surface. Finally, the washed Fe3O4 particles are dried in a vacuum drying oven at 60°C for 12 hours to obtain Fe3O4 cores with excellent magnetic properties.

[0031] Shell preparation Sol-gel raw material preparation: Tetrabutyl titanate was used as a TiO2 precursor, and zirconium n-propoxide was used as a ZrO2 precursor. Anhydrous ethanol was used as the solvent, glacial acetic acid was used to adjust the solution pH, and deionized water was used for the hydrolysis reaction.

[0032] Sol Preparation: First, measure 150 mL of anhydrous ethanol and divide it into two portions. Add 20 mL of tetrabutyl titanate to one portion and stir thoroughly. Then, add 5 mL of glacial acetic acid dropwise and continue stirring for 30 minutes to obtain Solution A. Add 15 mL of zirconium n-propoxide to the other portion of anhydrous ethanol and stir thoroughly to obtain Solution B. While stirring, slowly add Solution B dropwise to Solution A. Subsequently, add 10 mL of deionized water dropwise and continue stirring for 2 hours to form a uniform, transparent sol.

[0033] Gel Formation and Aging: The prepared sol was transferred to a clean Petri dish and left at room temperature to allow the solvent to evaporate slowly and further polycondensation to occur, gradually forming a gel. The gel was then aged in a constant temperature and humidity chamber at 50°C and 60% relative humidity for 24 hours to stabilize the gel structure.

[0034] Loading and Calcination: The prepared Fe₃O₄ cores were added to the aged gel and stirred thoroughly to ensure that the gel was evenly coated on the surface of the Fe₃O₄ particles. Subsequently, the gel-loaded Fe₃O₄ particles were placed in a muffle furnace and heated from room temperature to 450°C at a rate of 3°C / min under a nitrogen atmosphere. They were then calcined at this temperature for 4 hours (magnetic retention after calcination was 95%). During the calcination process, the organic matter in the gel gradually decomposed and volatilized, and the TiO₂ and ZrO₂ precursors were converted into a TiO₂@ZrO₂ composite oxide, forming a shell structure tightly enveloping the Fe₃O₄ core, ultimately yielding core-shell catalyst particles 241.

[0035] Device Construction: A rapid marine aquaculture tailwater purification device was constructed according to the above-mentioned technical solution. The pore size of the coarse filter 11 in the pretreatment unit 1 was selected to be 0.5 mm. Polyaluminum chloride was added to the coagulant dosing device 121 in the flocculation flotation tank 12 at a dosage of 30 mg / L. The dissolved air water pressure generated by the air pump was set to 0.4 MPa. In the ultrasonic atomization system 21, the ultrasonic atomizer 212 operated at a frequency of 40 kHz, atomizing a 3% hydrogen peroxide solution. The ozone generator 221 generated ozone at a flow rate of 10 g / h. The motive gas (air) delivery velocity was controlled at 0.6 m / s, and the pitch of the spiral guide plates in the motive gas delivery pipe 222 was 5 cm. Within reaction chamber 23, the framework 2421 of the catalytic structure 24 is a 30 cm cubic titanium alloy frame. The bottom edge of the alloy frame is equipped with a 20° diversion groove to guide the aerated liquid flow. The loading unit 2422 contains 20 mesh bags, each containing approximately 500 g of catalyst particles 241. The catalyst particles 241 are spherical and have a particle size of 3 mm. The catalytic structure 24 is suspended 15 cm above the aeration structure 25 by a suspension device 243. The membrane separation unit 3 utilizes a polyvinylidene fluoride hollow fiber ultrafiltration membrane module 31 with a pore size of 0.05 μm. The backwash system operates at a backwash pressure of 0.4 MPa and an ultrasonic cleaning frequency of 40 kHz. The backwash cycle is set to occur every 4 hours of operation, lasting 15 minutes each time.

[0036] Tail water purification treatment: Take 10m3 of marine aquaculture tail water containing 150mg / L COD, 30mg / L ammonia nitrogen, 200mg / L suspended solids and 32‰ salinity. 3 , with 1m 3 The flow rate of / h is processed in sequence through the pretreatment unit 1, the atomization catalytic reaction unit 2 and the membrane separation unit 3.

[0037] Test results: After treatment, the tailwater quality showed COD reduced to 10 mg / L, ammonia nitrogen to 0.5 mg / L, suspended solids to 8 mg / L, and turbidity reduced from an initial 100 NTU to 5 NTU, meeting all discharge standards for marine aquaculture tailwater. Throughout the treatment process, ozone utilization reached 85%, a 35% improvement compared to traditional ozone-hydrogen peroxide treatment equipment. Catalyst particles 241, after recovery through magnetic separation, lost only 3% of their activity and are reusable.

[0038] Example 2 Catalyst particle preparation: Core preparation Materials Preparation: Ferric chloride hexahydrate and ferrous chloride tetrahydrate are used as the iron source. Ammonia is used as the precipitant at a concentration of 25%. Deionized water is also available for solution preparation and subsequent cleaning steps.

[0039] Coprecipitation reaction: According to the molar ratio of Fe 3+ :Fe 2+ = 2:1. Accurately weigh a certain amount of ferric chloride hexahydrate and ferrous chloride tetrahydrate and dissolve them in deionized water to prepare a mixed solution with a total iron ion concentration of 0.5 mol / L. While stirring, slowly add this mixed solution dropwise at 1.5 mL / min to a reaction vessel containing excess ammonia. During the addition, maintain the reaction system temperature at 75°C and stir continuously at 400 rpm to ensure sufficient reaction progress. This generates the Fe₃O₄ precursor.

[0040] Product Isolation and Cleaning: After the reaction is complete, magnetic separation technology is used to rapidly separate the resulting Fe3O4 magnetic particles from the reaction mixture using a strong magnet. The separated particles are then washed multiple times with deionized water until the pH of the washing solution reaches approximately 7 to remove impurity ions adsorbed on the particle surface. Finally, the washed Fe3O4 particles are dried in a vacuum drying oven at 60°C for 12 hours to obtain Fe3O4 cores with excellent magnetic properties.

[0041] Shell preparation Sol-gel raw material preparation: Tetrabutyl titanate was used as a TiO2 precursor, and zirconium n-propoxide was used as a ZrO2 precursor. Anhydrous ethanol was used as the solvent, glacial acetic acid was used to adjust the solution pH, and deionized water was used for the hydrolysis reaction.

[0042] Sol Preparation: First, measure 200 mL of anhydrous ethanol and divide it into two portions. Add 30 mL of tetrabutyl titanate to one portion and stir thoroughly. Then, add 8 mL of glacial acetic acid dropwise and continue stirring for 30 minutes to obtain Solution A. Add 25 mL of zirconium n-propoxide to the other portion of anhydrous ethanol and stir thoroughly to obtain Solution B. While stirring, slowly add Solution B dropwise to Solution A. Subsequently, add 15 mL of deionized water dropwise and continue stirring for 2 hours to form a uniform, transparent sol.

[0043] Gel Formation and Aging: The prepared sol was transferred to a clean Petri dish and left at room temperature to allow the solvent to evaporate slowly and further polycondensation to occur, gradually forming a gel. The gel was then aged in a constant temperature and humidity chamber at 50°C and 60% relative humidity for 24 hours to stabilize the gel structure.

[0044] Loading and Calcination: The prepared Fe₃O₄ cores were added to the aged gel and stirred thoroughly to ensure that the gel was evenly coated on the surface of the Fe₃O₄ particles. Subsequently, the gel-loaded Fe₃O₄ particles were placed in a muffle furnace and heated from room temperature to 480°C at a rate of 2°C / min under a nitrogen atmosphere. They were then calcined at this temperature for 3 hours (magnetic retention after calcination was 90%). During the calcination process, the organic matter in the gel gradually decomposed and volatilized, and the TiO₂ and ZrO₂ precursors were converted into a TiO₂@ZrO₂ composite oxide, forming a shell structure tightly enveloping the Fe₃O₄ core, ultimately yielding core-shell catalyst particles 241.

[0045] Device parameter adjustment: Compared with Example 1, the dosage of coagulant polyaluminium chloride in the pretreatment unit 1 is adjusted to 40 mg / L, and the dissolved air water pressure generated by the dissolved air pump is 0.5 MPa. The operating frequency of the ultrasonic atomizer 212 of the ultrasonic atomization system 21 is adjusted to 50 kHz, the mass fraction of the hydrogen peroxide solution is adjusted to 5%, the ozone generation amount is adjusted to 12 g / h, the power gas delivery flow rate is adjusted to 0.8 m / s, and the number of turbulent elements in the mixing chamber 223 is increased to 10. In the reaction chamber 23, the guide groove angle of the frame structure 2421 of the catalytic structure 24 is adjusted to 25°, and the number of mesh bags of the load unit 2422 is increased to 25; the particle size of the catalyst particles 241 is adjusted to 4 mm. The backwash pressure of the membrane separation unit 3 is adjusted to 0.5 MPa, and the backwash cycle is adjusted to once every 3 hours of operation, each lasting 20 minutes.

[0046] Tail water purification treatment: Take 20m3 of marine aquaculture tail water containing 200mg / L COD, 40mg / L ammonia nitrogen, 300mg / L suspended solids and 35‰ salinity, and use 1.5m 3 / h flow rate is processed.

[0047] Test results: After treatment, the COD content of the tailwater dropped to 15 mg / L, ammonia nitrogen to 1.0 mg / L, suspended solids to 12 mg / L, and turbidity to 6 NTU, meeting discharge requirements. During operation, the membrane flux remained above 90% of its initial value, with minimal contaminants adhering to the ultrafiltration membrane surface. After backwashing, membrane performance recovered well.

[0048] Comparative Example 1 A conventional pressure atomizer was used to atomize the hydrogen peroxide solution, and the solution was simply mixed with ozone and then aerated to treat the marine aquaculture tail water. No pretreatment unit and membrane separation unit were used. Other conditions of the device were the same as those in Example 1. 10 m3 of marine aquaculture tail water containing 150 mg / L COD, 30 mg / L ammonia nitrogen, 200 mg / L suspended solids, and 32‰ salinity was taken. 3After treatment, the tail water quality was tested, COD was 70mg / L, ammonia nitrogen was 18mg / L, and suspended solids were 80mg / L. The treatment effect was far lower than that of the device of the present invention. At the same time, the ozone utilization rate during the operation of the traditional device was only 50%, and the catalyst was only 10% after treating 5m 3 The activity of tail water decreases significantly and needs to be replaced frequently.

[0049] Comparative Example 2 An ozone-hydrogen peroxide treatment device using an existing fixed-bed catalyst was used, without an ultrasonic atomization system. Hydrogen peroxide was added directly to the reaction chamber, with other conditions similar to those in Example 1. Treating marine aquaculture tailwater of the same water quality and quantity, the treated tailwater had a COD of 65 mg / L, ammonia nitrogen of 16 mg / L, and an ozone utilization rate of 55%. Due to insufficient gas-liquid contact between the fixed-bed catalyst and the catalyst, the catalytic efficiency was low, and the catalyst was difficult to replace and recycle, resulting in high operating costs.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rapid purification device for seawater aquaculture tail water, characterized in that: It comprises a pretreatment unit (1), an atomization catalytic reaction unit (2) and a membrane separation unit (3) which are connected in sequence; The atomizing catalytic reaction unit (2) comprises: an ultrasonic atomization system (21) for atomizing the hydrogen peroxide solution into tiny droplets; A gas mixing and delivery assembly (22) is used to mix ozone with atomized hydrogen peroxide droplets to form an oxidizing mixed gas; A reaction chamber (23) is provided with a catalytic structure (24) therein, and an aeration structure (25) is provided at the bottom of the reaction chamber (23). The aeration structure (25) is communicated with the gas mixing and conveying assembly (22) and is used to release the oxidizing mixed gas into the reaction chamber (23) in the form of bubbles; The outlet of the pretreatment unit (1) is connected to the inlet of the reaction chamber (23), and the outlet of the reaction water of the reaction chamber (23) is connected to the inlet of the membrane separation unit (3).

2. The rapid purification device for seawater aquaculture tail water according to claim 1, characterized in that: The ultrasonic atomization system (21) comprises a hydrogen peroxide storage tank (211) and an ultrasonic atomizer (212). The ultrasonic atomizer (212) operates at a frequency of 40-60 kHz and is used to atomize the hydrogen peroxide solution into tiny droplets with a particle size of 1-10 μm.

3. The rapid purification device for seawater aquaculture tail water according to claim 1, characterized in that: The gas mixing and delivery assembly (22) comprises an ozone generator (221) and a motive gas delivery pipeline (222). The motive gas delivery pipeline (222) is used to fully mix ozone and hydrogen peroxide droplets. The motive gas is air, and the mixed gas delivery flow rate in the motive gas delivery pipeline (222) is 0.5-1 m / s.

4. The rapid purification device for seawater aquaculture tail water according to claim 1, characterized in that: The catalytic structure (24) includes catalyst particles (241) and a carrier assembly (242). The catalyst particles (241) are of a core-shell structure, wherein the core is magnetic Fe3O4 and the shell is a TiO2@ZrO2 composite oxide. The carrier assembly (242) includes a frame structure (2421) and a plurality of load units (2422) arranged on the frame. The load units (2422) are of a mesh bag structure for fixing the catalyst particles (241).

5. The rapid purification device for seawater aquaculture tail water according to claim 4, characterized in that: The catalyst particles (241) are spherical or quasi-spherical, with a particle size of 2-5 mm, a molar ratio of TiO2 to ZrO2 of 1:1, and a catalyst loading of 5-10 g / m 2 .

6. The rapid purification device for seawater aquaculture tail water according to claim 4, characterized in that: The frame structure (2421) is detachably hung in the reaction chamber (23) via a suspension device (243), wherein the suspension device (243) includes a support arm (2431) connected to the top of the reaction chamber (23) and a detachable connector (2432) connecting the support arm (2431) and the frame structure (2421).

7. The rapid purification device for seawater aquaculture tail water according to claim 1, characterized in that: The catalytic structure (24) is arranged above the aeration structure (25), and the distance between the two is 10-20 cm.

8. The rapid purification device for seawater aquaculture tail water according to claim 1, characterized in that: The pretreatment unit (1) comprises a coarse filter (11) and a flocculation flotation tank (12) which are connected in sequence.

9. The rapid purification device for seawater aquaculture tail water according to claim 1, characterized in that: The membrane separation unit (3) adopts a hollow fiber ultrafiltration membrane assembly (31) of a cross-flow filtration method. The ultrafiltration membrane is made of polyvinylidene fluoride and has a membrane pore size of 0.01-0.1 μm.

10. The rapid purification device for seawater aquaculture tail water according to claim 1, characterized in that: The ultrasonic atomization system (21), the gas mixing and delivery component (22), the catalytic structure (24) and the reaction chamber (23) are connected via a sealed pipe, and the sealed pipe is made of corrosion-resistant polyvinyl chloride.

Images