A device and method for photodegradation of wastewater containing pesticides

Abstract

The application discloses a kind of photodegradation device and photodegradation method of containing pesticide sewage, including the sewage introduction system connected in turn, atomization unit, atomization unit bottom is equipped with water collecting pipe, water collecting pipe is connected with water body collection chamber;The atomization unit is equipped with atomization droplet reaction chamber, top is equipped with light source installation chamber, is equipped with reflection enhancement device on outer wall;Atomization droplet reaction chamber and reflection enhancement device are equipped with circulation temperature control water bath interlayer between;Photodegradation device is used in series or parallel, and the photodegradation treatment of containing pesticide sewage is carried out.The degradation characteristics of the atomization droplet itself is strengthened in the application, and specific wavelength light source is matched to irradiate, and the photodegradation efficiency of polluted water body can be improved without relying on photocatalyst, and the problems of secondary pollution, high cost, complex operation and potential biological toxicity existing in the current ultrasonic atomization photodegradation technology using photocatalyst are solved.

Description

Technical Field

[0001] This invention belongs to the field of water pollution treatment technology, specifically relating to a photodegradation device and method for pesticide-containing wastewater. Background Technology

[0002] In modern agricultural production, the production and use of pesticides are unavoidable. This production and use of pesticides causes water pollution, and pesticide wastewater contains high concentrations of organic matter. This organic matter is not only difficult to degrade but also poses serious harm to the environment and organisms. Furthermore, the wastewater may contain various toxic and harmful substances, such as phenols, arsenic, and mercury. These substances are toxic to aquatic life and can be transferred through the food chain, posing a potential threat to human health. The composition of pesticide wastewater is complex and unstable; different types of pesticide production processes produce wastewater with different properties, and the types and concentrations of pollutants in the wastewater change with time and production processes. This makes treatment extremely difficult and requires a comprehensive approach using multiple technologies.

[0003] Currently, the main methods for treating pesticide-contaminated water are chemical methods, including ozone treatment, iron-carbon micro-electrolysis, and combined ozone / iron-carbon micro-electrolysis processes. These methods utilize strong oxidants or electrochemical reduction to remove organic matter and toxic substances from the water. The difficulty in treating pesticide-contaminated water lies in its high concentration of organic matter, complex composition, and resistance to biodegradation. Wastewater generated during pesticide production can have a COD value as high as hundreds of thousands of mg / L and contains toxic substances such as benzene ring compounds, phenols, arsenic, and mercury. These substances are difficult for microorganisms to degrade and may even kill the microorganisms used for wastewater treatment.

[0004] Photocatalytic degradation of water pollution is a highly efficient wastewater treatment technology. It utilizes photocatalysts to convert organic pollutants in water into harmless substances under light irradiation, offering advantages such as high efficiency, environmental friendliness, and energy conservation. The basic principle is that the photocatalyst absorbs light energy under illumination, generating electron-hole pairs, which then react with adsorbed organic matter on the surface in a redox reaction to produce inorganic substances. In recent years, researchers have developed various novel photocatalysts, such as the CuO / TiO2 catalyst, which can convert trichloromethylphosphine into phosphate and chloride ions under ultraviolet light irradiation. Chinese patent CN103771638A discloses a photocatalytic method that enhances wastewater treatment through ultrasonic atomization. The method breaks down wastewater containing photocatalysts into micron-sized droplets. Under light irradiation, the photocatalyst is excited to generate photoactive species that catalytically oxidize pollutants in the liquid film, producing carbon dioxide, water, and other detoxification and degradation byproducts. This invention, aided by ultrasonic atomization, reduces the external diffusion resistance of the particle surface, enhances mass transfer efficiency, improves the utilization rate of the photocatalyst surface, prevents catalyst poisoning, and utilizes the liquid film on the photocatalyst surface as a reaction medium to reduce light diffusion and absorption losses, improve light energy utilization, and simultaneously increase photocatalyst utilization while preventing problems such as catalyst agglomeration and precipitation leading to decreased catalytic activity. Chinese patent CN 113526757 B discloses a wastewater treatment device and method, including a shell with an inlet on the upper side and an outlet on the lower side. The shell contains a light-illuminating area, which includes at least one photodegradation unit and a light source for illuminating the photodegradation unit. The inlet of the photodegradation unit is connected to the inlet, and its outlet is connected to the outlet. The photodegradation unit contains multiple diaphragms that divide it into multiple segments for recovering catalyst sloughed off from the previous photodegradation unit.

[0005] However, current methods for degrading water pollution still rely on photocatalysts. Commonly used photocatalysts include TiO2, ZnO, CdS, and ZnS. However, among these photocatalysts, CdS and ZnS are chemically unstable and may produce harmful metal ions during photocatalysis, exhibiting potential biotoxicity. TiO2, on the other hand, can easily harm the human body, causing everything from mild allergies to severe organ damage and even potential carcinogenic risks. This indicates that photocatalysts may cause secondary pollution of water bodies and affect water purification quality, thus harming organisms. Furthermore, the use of photocatalysts in photocatalysis increases wastewater treatment costs, catalyst recovery is difficult, and its loss and distribution can affect treatment efficiency and equipment operation. Although activated carbon adsorption, membrane filtration, and precipitation methods can be used to treat photocatalysts, these methods still have the drawback of not being able to completely collect and reuse them. In conclusion, among current photocatalytic technologies for degrading water pollution, adding photocatalysts to pesticide-contaminated water to degrade pesticide residues is the mainstream method. However, the bottleneck of existing photocatalytic technologies lies in the fact that, to avoid the difficulties of catalyst separation and recovery, most processes use immobilized catalysts, which leads to new problems such as decreased catalytic efficiency and limited reaction interfaces. Therefore, there is an urgent need for a new technological approach that can maintain high photodegradation efficiency while completely avoiding secondary pollution. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a photodegradation device and method for pesticide-containing wastewater. By enhancing the degradation characteristics of the atomized droplets themselves and matching them with a specific wavelength light source for irradiation, the photodegradation efficiency of polluted water can be improved without relying on a photocatalyst. This solves the problems of secondary pollution, high cost, complex operation, and potential biotoxicity associated with existing ultrasonic atomization photodegradation technologies that use photocatalysts.

[0007] To achieve the above objectives, the present invention provides a photodegradation device for pesticide-containing wastewater, comprising a wastewater inlet system and an atomizing unit connected in sequence. The atomizing unit has a water collection pipe at its bottom, which is connected to a water collection chamber. The atomizing unit has an atomized droplet reaction chamber inside, a light source installation chamber at its top, and a reflection enhancement device on its outer wall. A circulating temperature-controlled water bath partition is provided between the atomized droplet reaction chamber and the reflection enhancement device.

[0008] Preferably, the bottom of the atomizing droplet reaction chamber is provided with a sealing gasket, an RFID tag and a mounting base, the interior is provided with multiple baffles, and the top is provided with a homogenizing chamber.

[0009] More preferably, the baffle is fixed on the baffle fixing member, the baffle fixing member is fixedly connected to the fixing rope, and the fixing rope is connected to the fixing hook in the homogenization chamber; the homogenization chamber is divided into upper and lower parts and connected by a quick-release flange; the homogenization chamber contains homogenizing balls, which are Φ5mm steel balls.

[0010] More preferably, the baffle fixing component is provided with a baffle fixing hook; the baffle is composed of a baffle base and a baffle coating.

[0011] Furthermore, the baffle has holes of 0.2-5mm; the thickness of the baffle coating is 1.0-2.0μm, and the contact angle with water is ≤10°.

[0012] Furthermore, the baffle has 2-5 layers; more preferably, when the number of baffle layers is 2-3, the generated droplet size is 50-100μm and the baffle pore size is 3-5mm; when the number of baffle layers is 3-4, the generated droplet size is 5-15μm and the baffle pore size is 0.5-2mm; when the number of baffle layers is 4-5, the generated droplet size is 1-5μm and the baffle pore size is 0.1-0.5mm.

[0013] More preferably, the baffle coating is made of silica nanoparticles and fluorosilane coupling agents via a sol-gel method.

[0014] Preferably, the bottom of the light source installation chamber is provided with a first light source module, a second light source module, and a third light source module; the first light source module, the second light source module, and the third light source module are respectively connected to the drive circuit; the upper part of the light source installation chamber is provided with an RFID reader / writer, and the top is provided with a heat sink and a central control screen.

[0015] More preferably, the illuminance of the first light source module, the second light source module, and the third light source module is 1.5-15 mW / cm². 2 .

[0016] More preferably, the first light source module is a UVC light source with a wavelength of 240-280nm and a light intensity of 1.5-3.0 mW / cm². 2 The second light source module is a UVA light source with a wavelength of 300-400nm and a light intensity of 3.0-6.0mW / cm². 2 The third light source module is a blue light source with a wavelength of 450-500nm and a light intensity of 8.0-15.0 mW / cm². 2 .

[0017] Preferably, the wastewater introduction system consists of a pretreatment filter and an inlet pipe connected in sequence; the inlet pipe is equipped with a pressure regulating valve; the water collection chamber includes a water storage tank; the outlet pipe of the water storage tank is equipped with a valve; the reflection enhancement device has multiple prisms embedded in it; and the circulating temperature-controlled water bath is circulatedly connected to the water storage tank.

[0018] More preferably, the number of prisms is 1000-1500, the size is 2cm×1cm, and the arrangement density is 25-30 prisms / cm. 2 Reflectivity ≥ 95%.

[0019] This invention also provides a continuous photodegradation method for pesticide-containing wastewater, comprising the following steps:

[0020] (1) Connect the above photodegradation devices in series to form a continuous multi-stage photodegradation treatment system; (2) Pesticide-containing wastewater is fed into a multi-stage photodegradation treatment system. The atomization unit and the light source installation chamber are turned on to atomize the pesticide-containing wastewater into droplets of 1-100 μm and irradiate them with visible light of 240-500 nm for photodegradation. (3) The pesticide-containing wastewater stays in each stage of photodegradation treatment device for 10-60 minutes, and after purification, it is discharged from the water collection chamber of the last stage device to complete the photodegradation.

[0021] Preferably, the multi-stage photodegradation treatment system has three stages: the first stage uses UVC light with a droplet size of 50-100 μm and a visible light wavelength of 240-280 nm; the second stage uses UVA light with a droplet size of 5-15 μm and a visible light wavelength of 300-400 nm; and the third stage uses blue light with a droplet size of 1-5 μm and a visible light wavelength of 450-500 nm.

[0022] This invention also provides a rapid photodegradation method for pesticide-containing wastewater, comprising the following steps: (1) Connect the above photodegradation devices in parallel to form a photodegradation treatment system; (2) Simultaneously introduce pesticide-containing wastewater into the photodegradation treatment system, turn on the atomization unit and the light source installation chamber, atomize the pesticide-containing wastewater into droplets of 1-100μm, and irradiate it with 240-500mm visible light for photodegradation; (3) Wastewater containing pesticides stays in each photodegradation treatment device for 10-60 minutes, and after purification, it is discharged from the water collection chamber of each photodegradation treatment device and collected uniformly to complete the photodegradation.

[0023] Preferably, the parameters of the pesticide-containing wastewater are: COD concentration 800-3000 mg / L, BOD concentration 200-1000 mg / L, ammonia nitrogen concentration 80-200 mg / L, and total phosphorus concentration 5-20 mg / L.

[0024] The beneficial effects of this invention are as follows: 1. Construct a photodegradation device to fully utilize and enhance the spontaneous degradation ability of atomized droplets, as well as the high chemical reactivity and rapid oxygen mass transfer characteristics at the gas-liquid interface, thereby improving the utilization efficiency of light energy and dissolved oxygen and significantly increasing the photodegradation rate.

[0025] 2. This invention completely avoids the secondary water pollution problems that may arise from the use of photocatalysts, while simplifying the process flow and helping to reduce the overall cost of factory wastewater treatment. Simultaneously, atomization greatly increases the effective contact area between wastewater and light, thereby improving the chemical reaction rate. The system can adapt to light sources of varying intensities, including UVA, blue light, and even natural sunlight, improving the utilization rate of low-power light sources or natural light, which is beneficial for large-scale wastewater treatment applications. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the photodegradation device.

[0027] Figure 2 This is a cross-sectional view of the atomizing unit.

[0028] Figure 3 This is a cross-sectional view of the atomized droplet reaction chamber.

[0029] Figure 4 This is a structural diagram of the baffle and its fixing components; A in the diagram is the baffle, and B is the baffle fixing component.

[0030] Figure 5 This is a schematic diagram of the reflection enhancement device.

[0031] Figure 6 This is a top view of the light source installation room; A in the figure is a structural schematic diagram of the light source module, and B is a structural schematic diagram of the heat sink and the central control screen.

[0032] In the diagram, 1 represents the wastewater introduction system, 101 is the inlet pipe, 102 is the pressure regulating valve, 103 is the pretreatment filter, 2 is the atomizing unit, 3 is the atomizing droplet reaction chamber, 301 is the mounting base, 302 is the baffle, 3021 is the baffle substrate, 3022 is the baffle coating, 3023 is the baffle fixing component, 3024 is the baffle fixing hook, 3035 is the fixing rope, 303 is the homogenization chamber, 304 is the quick-release flange, 305 is the fixing hook, and 306 is the homogenizing ball. 07 is an RFID tag, 308 is a sealing ring, 4 is a light source installation chamber, 401 is the first light source module, 402 is the second light source module, 403 is the third light source module, 404 is a drive circuit, 405 is an RFID reader / writer, 406 is a heat sink, 407 is a central control screen, 5 is a reflection enhancement device, 501 is a prism, 6 is a circulating temperature-controlled water bath partition, 7 is a water collection pipe, 8 is a water collection chamber, 801 is a water storage tank, 802 is a valve, and 9 is a water storage tank. Detailed Implementation

[0033] The technical solution of the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention should be determined by the contents of the claims. Modifications and substitutions made by those skilled in the art to the technical solution of the present invention without creative effort all fall within the scope of protection of the present invention.

[0034] Example 1 like Figure 1-6 The device for photodegrading pesticide-containing wastewater includes a wastewater inlet system 1 and an atomizing unit 2 connected in sequence. The atomizing unit 2 has a water collection pipe 7 at its bottom, which is connected to a water collection chamber 8. The pesticide-containing wastewater is input through the wastewater inlet system 1, undergoes atomization and photodegradation in the atomizing unit 2, and is then collected and stored in the water collection chamber 8 through the water collection pipe 7, and periodically discharged. The atomizing unit 2 has an atomizing droplet reaction chamber 3 to atomize the pesticide-containing wastewater into small droplets, allowing it to receive sufficient energy to drive the interfacial photosensitization reaction and achieve photodegradation. The top has a light source installation chamber 4, which houses different types of light sources to meet the degradation needs of pesticide-containing wastewater from different pollution sources. A reflection enhancement device 5 is installed on the outer wall to reflect and enhance the light energy of the light sources, improving the treatment efficiency of the pesticide-containing wastewater. A circulating temperature-controlled water bath 6 is provided between the atomizing droplet reaction chamber 3 and the reflection enhancement device 5, maintaining the temperature in the atomizing unit 2 within a suitable range through circulating constant-temperature water, promoting the photodegradation reaction as positively as possible.

[0035] Preferably, the bottom of the atomizing droplet reaction chamber 3 is provided with a sealing gasket 308 to prevent water leakage, and an RFID tag 307 to facilitate the main control unit to identify the nozzle type and automatically control and adjust the corresponding light source in the light source installation chamber 4 and the mounting base 301 for quick installation and disassembly of the atomizing droplet reaction chamber 3. The interior is provided with multiple baffles 302 to perform multi-stage atomization of pesticide-containing wastewater, gradually obtaining small droplets of the corresponding particle size; the top is provided with a homogenization chamber 303 to evenly disperse the atomized small droplets into the atomizing unit 2 so as to fully contact the light source and promote the interfacial photosensitization reaction.

[0036] More preferably, the baffle 302 is fixed on the baffle fixing member 3023, the baffle fixing member 3023 is fixedly connected to the fixing rope 3035, the fixing rope 3035 is connected to the fixing hook 305 in the homogenization chamber 303, the top of the baffle fixing member 3023 is fixed to the bottom of the homogenization chamber 303, and the lower part extends into the tubular part at the bottom of the atomized droplet reaction chamber 3, so as to fix the baffle 302; the homogenization chamber 303 is divided into upper and lower parts and connected by a quick-release flange 304; the homogenization chamber 303 contains homogenizing balls 306, which are Φ5mm steel balls, so as to facilitate opening the homogenization chamber to maintain or replace the steel balls inside, and at the same time, the steel balls can improve the homogenization efficiency and promote the uniform distribution of atomized droplets.

[0037] More preferably, the baffle fixing member 3023 is provided with a baffle fixing hook 3024 for fixing the baffle 302. At the same time, the position of the baffle 302 on the baffle fixing hook 3024 can be adjusted, thereby adjusting the spacing and number of baffles 302, and replacing baffles 302 with different apertures to adapt to different working configurations. For example, when it is necessary to produce small droplets of 50-100μm, the number of baffle layers is 2-3 layers, and the aperture range of each layer of baffles is 3-5mm; when it is necessary to produce small droplets of 5-15μm, the number of baffle layers is 3-4 layers, and the aperture range of each layer of baffles is 0.5-2mm; when it is necessary to produce small droplets of 1-5μm, the number of baffle layers is 4-5 layers, and the aperture range of each layer of baffles is 0.1-0.5mm. More preferably, the baffle 302 is composed of a baffle substrate 3021 and a baffle coating 3022. The baffle substrate 3021 is a 316L stainless steel baffle, and the baffle coating 3022 is a superhydrophilic nano-coating made of silica nanoparticles and a fluorosilane coupling agent via a sol-gel method, which can promote droplet spreading and breakup.

[0038] Furthermore, the baffle 302 is provided with holes of 0.2-5mm; the thickness of the baffle coating 3022 is 1.5μm, and the contact angle with water is ≤10°.

[0039] Furthermore, the baffle 302 has 2-5 layers; more preferably, when the number of baffle 302 layers is 2-3, the generated droplet particle size is 50-100μm, and the pore size of the baffle 302 is 3-5mm; when the number of baffle 302 layers is 3-4, the generated droplet particle size is 5-15μm, and the pore size of the baffle 302 is 0.5-2mm; when the number of baffle layers is 4-5, the generated droplet particle size is 1-5μm, and the pore size of the baffle 302 is 0.1-0.5mm, and then photodegradation is carried out in combination with light sources of different wavelengths.

[0040] More preferably, the baffle coating 3022 is made of silica nanoparticles and fluorosilane coupling agent by a sol-gel method.

[0041] Preferably, the bottom of the light source mounting chamber 4 is provided with a first light source module 401, a second light source module 402, and a third light source module 403, thereby providing light sources of different wavelengths to photodegrade pesticide-containing wastewater from different pollution sources; the first light source module 401, the second light source module 402, and the third light source module 403 are respectively connected to the drive circuit 404, and the drive circuit 404 controls the start and stop of different light source modules, thereby providing light of different wavelengths to the atomizing unit 2; the upper part of the light source mounting chamber 4 is provided with an RFID reader 405, which is used to identify the type of RFID tag 307 in the atomized droplet reaction chamber 3, thereby controlling the start and stop of different light source modules; the top is provided with a heat sink 406 to prevent the light source modules from overheating and malfunctioning, and a central control screen 407 for controlling the start and stop of each component in the atomizing unit 2.

[0042] More preferably, the illuminance of the first light source module 401, the second light source module 402, and the third light source module 403 is 1.5-15 mW / cm². 2 .

[0043] More preferably, the first light source module 401 is a UVC light source with a wavelength of 240-280nm and a light intensity of 1.5-3.0 mW / cm². 2 It utilizes its high photon energy to directly break CP bonds or excite strong oxidizing species such as hydroxyl radicals (·OH) to degrade stubborn pollutants, such as organophosphorus pesticides; the second light source module 402 is a UVA light source with a wavelength of 300-400nm and a light intensity of 3.0-6.0 mW / cm². 2 Effectively stimulates the production of singlet oxygen at the droplet interface. 1 O 2 The active species, such as [list of species], attack the C-Cl bond, thereby degrading organochlorine compounds; the third light source module 403 is a blue light source with a wavelength of 450-500 nm and a light intensity of 8.0-15.0 mW / cm². 2This provides sufficient energy to drive the interfacial photosensitization reaction, thereby achieving the degradation of benzene ring structures (such as aromatic compounds).

[0044] Preferably, the wastewater introduction system 1 consists of a pretreatment filter 103 and an inlet pipe 101 connected in sequence to perform preliminary filtration of pesticide-containing wastewater and avoid clogging; the inlet pipe 101 is equipped with a pressure regulating valve 102 to pump the pesticide-containing wastewater into the atomizing unit 2 at a pressure of 0.2-0.5 MPa for atomization; the water collection chamber 8 includes a water storage tank 801 to store the photodegraded wastewater; the outlet pipe of the water storage tank 801 is equipped with a valve 802 to periodically discharge the wastewater; the reflection enhancement device 5 has multiple embedded prisms 501 to reflect and enhance the light emitted by the light source module, thereby improving the light intensity and photodegradation effect; the circulating temperature-controlled water bath partition 6 is circulatedly connected to the water storage tank 9 to provide constant temperature water in a circulating manner, ensuring that the temperature in the atomizing unit 2 is maintained at a suitable level, thereby promoting the positive photocatalytic reaction.

[0045] More preferably, the number of prisms 501 is 1000-1500, the size is 2cm×1cm, and the arrangement density is 25-30 prisms / cm. 2 Reflectivity ≥ 95%.

[0046] Example 2 (1) Assemble the photodegradation device according to Example 1, and connect three photodegradation devices in series to form a three-stage photodegradation system. The first photodegradation device is used as the first-stage processing unit, the second photodegradation device is used as the second-stage processing unit, and the third photodegradation device is used as the third-stage processing unit. The first-stage processing unit has two layers of baffle 302 with apertures of 5mm and 3mm from bottom to top. The light source is a UVC light source (ZW30519W-Z894, Shenzhen Anhongda Optoelectronics Technology Co., Ltd.), with a wavelength of 253.7nm and a light intensity of 2.5 mW / cm². 2 The second-stage processing unit has three layers of baffle 302 with apertures of 2mm, 1mm, and 0.5mm from bottom to top. The light source is a UVA light source (ZW30519W-Z894, Shenzhen Anhongda Optoelectronic Technology Co., Ltd.), with a wavelength of 365nm and an illuminance of 4.8mW / cm². 2 The third-stage processing unit has four layers of baffle 302 with apertures of 0.5mm, 0.3mm, 0.2mm, and 0.1mm from bottom to top. The light source is a blue light source (composed of blue LED strips, Shenzhen Tuozhan Optoelectronics Co., Ltd.), with a wavelength of 470nm and a light intensity of 12 mW / cm². 2 ; (2) Take pesticide-containing wastewater (COD concentration of 1850 mg / L, BOD concentration of 680 mg / L, ammonia nitrogen concentration of 150 mg / L, and total phosphorus concentration of 15 mg / L) and introduce it into the three-stage photodegradation system assembled in step (1) at a pressure of 0.4 MPa, and let it stay in each treatment unit for 60 min; (3) After the three-stage photodegradation system is completed, the pesticide residue is detected by a pesticide residue detector (LB-NC24 pesticide residue detector, Qingdao Lubo Jianye Environmental Protection Technology Co., Ltd.).

[0047] The results showed that the degradation rate of organophosphorus pesticides in the water was >95%, and the degradation rate of organochlorine pesticides was >92%. The concentration of microbial communities at the microbial treatment end remained basically unchanged, with almost no harm to microorganisms. The COD concentration in the water decreased to 70 mg / L, the BOD concentration decreased to 18 mg / L, the ammonia nitrogen concentration decreased to 1.2 mg / L, and the total phosphorus concentration decreased to 0.32 mg / L.

[0048] Example 3 (1) Assemble the photodegradation device according to Example 1, and connect three photodegradation devices in series to form a three-stage photodegradation system. The first photodegradation device is used as the first-stage processing unit, the second photodegradation device is used as the second-stage processing unit, and the third photodegradation device is used as the third-stage processing unit. In the first-stage processing unit, the baffle 302 has 3 layers with apertures of 5mm, 4mm and 3mm from bottom to top, respectively. The light source is a UVC light source (ZW30519W-Z894, Shenzhen Anhongda Optoelectronic Technology Co., Ltd.), with a wavelength of 241nm and a light intensity of 1.5mW / cm. 2 The second-stage processing unit has four layers of baffle 302 with apertures of 2mm, 1.5mm, 1mm, and 0.5mm from bottom to top. The light source is a UVA light source (ZW30519W-Z894, Shenzhen Anhongda Optoelectronic Technology Co., Ltd.), with a wavelength of 304nm and an illuminance of 3.0mW / cm². 2 The third-stage processing unit has five layers of baffle 302 with apertures of 0.5mm, 0.4mm, 0.3mm, 0.2mm, and 0.1mm from bottom to top. The light source is a blue light source (composed of blue LED strips, Shenzhen Tuozhan Optoelectronics Co., Ltd.), with a wavelength of 450nm and a light intensity of 8mW / cm². 2 ; (2) Take pesticide-containing wastewater (COD concentration of 1850 mg / L, BOD concentration of 680 mg / L, ammonia nitrogen concentration of 150 mg / L, and total phosphorus concentration of 15 mg / L) and introduce it into the three-stage photodegradation system assembled in step (1) at a pressure of 0.2 MPa, and let it stay in each treatment unit for 60 min; (3) After the three-stage photodegradation system is completed, the pesticide residue is detected by a pesticide residue detector (LB-NC24 pesticide residue detector, Qingdao Lubo Jianye Environmental Protection Technology Co., Ltd.).

[0049] The results showed that the degradation rate of organophosphorus pesticides in the water was 95%, and the degradation rate of organochlorine pesticides was 84%. The concentration of microbial communities remained basically unchanged, with almost no harm to microorganisms. The COD concentration in the water decreased to 67 mg / L, the BOD concentration decreased to 21 mg / L, the ammonia nitrogen concentration decreased to 1.2 mg / L, and the total phosphorus concentration decreased to 0.2 mg / L.

[0050] Example 4 (1) Assemble the photodegradation device according to Example 1, and connect three photodegradation devices in series to form a three-stage photodegradation system. The first photodegradation device is used as the first-stage processing unit, the second photodegradation device is used as the second-stage processing unit, and the third photodegradation device is used as the third-stage processing unit. In the first-stage processing unit, the baffle 302 has two layers with apertures of 5mm and 4mm from bottom to top, respectively. The light source is a UVC light source (ZW30519W-Z894, Shenzhen Anhongda Optoelectronic Technology Co., Ltd.), with a wavelength of 280nm and a light intensity of 3.0mW / cm². 2 The second-stage processing unit has three layers of baffle 302 with apertures of 2mm, 1.5mm, and 1mm from bottom to top. The light source is a UVA light source (ZW30519W-Z894, Shenzhen Anhongda Optoelectronic Technology Co., Ltd.), with a wavelength of 400nm and an illuminance of 6.0mW / cm². 2 The third-stage processing unit has four layers of baffle 302 with apertures of 0.5mm, 0.4mm, 0.3mm, and 0.2mm from bottom to top. The light source is a blue light source (composed of blue LED strips, Shenzhen Tuozhan Optoelectronics Co., Ltd.), with a wavelength of 500nm and a light intensity of 15mW / cm². 2 ; (2) Take pesticide-containing wastewater (COD concentration of 1850 mg / L, BOD concentration of 680 mg / L, ammonia nitrogen concentration of 150 mg / L, and total phosphorus concentration of 15 mg / L) and introduce it into the three-stage photodegradation system assembled in step (1) at a pressure of 0.5 MPa, and let it stay in each treatment unit for 60 min. (3) After the three-stage photodegradation system is completed, the pesticide residue is detected by a pesticide residue detector (LB-NC24 pesticide residue detector, Qingdao Lubo Jianye Environmental Protection Technology Co., Ltd.).

[0051] The results showed that the degradation rate of organophosphorus pesticides in the water was 98%, and the degradation rate of organochlorine pesticides was 92%. The concentration of microbial communities at the microbial treatment end remained basically unchanged, and there was almost no harm to microorganisms. The COD concentration in the water decreased to 70 mg / L, the BOD concentration decreased to 18 mg / L, the ammonia nitrogen concentration decreased to 1.2 mg / L, and the total phosphorus concentration decreased to 0.32 mg / L.

[0052] Comparative Example 1 The method and steps are the same as in Example 2, except that the three-stage photodegradation system is changed to a single-stage photodegradation system, that is, only one photodegradation device is used to treat pesticide-containing wastewater, and the retention time is 60 minutes.

[0053] The results showed that the COD concentration in the water body decreased to 89 mg / L, the BOD concentration decreased to 35 mg / L, the ammonia nitrogen concentration decreased to 1.2 mg / L, the total phosphorus concentration decreased to 0.2 mg / L, the degradation rate of organophosphorus pesticides was 86%, and the degradation rate of organochlorine pesticides was 66%.

[0054] Comparative Example 2 The method and steps are the same as in Example 2, except that the light sources of the first and second stage processing units of the three-stage photodegradation system are interchanged. Specifically, the first stage processing unit uses a UVA light source (ZW30519W-Z894, Shenzhen Anhongda Optoelectronic Technology Co., Ltd.) with a wavelength of 365nm and an illuminance of 4.8mW / cm². 2 The second-stage processing unit uses a UVC light source (ZW30519W-Z894, Shenzhen Anhongda Optoelectronic Technology Co., Ltd.) with a wavelength of 253.7nm and an illuminance of 2.5 mW / cm². 2 .

[0055] The results showed that the COD concentration in the water body decreased to 82 mg / L, the BOD concentration decreased to 20 mg / L, the ammonia nitrogen concentration decreased to 1.3 mg / L, the total phosphorus concentration decreased to 0.3 mg / L, the degradation rate of organophosphorus pesticides was 75%, and the degradation rate of organochlorine pesticides was 56%.

[0056] Comparative Example 3 (1) Take wastewater containing pesticides (COD concentration of 1850 mg / L, BOD concentration of 680 mg / L, ammonia nitrogen concentration of 150 mg / L, total phosphorus concentration of 15 mg / L), add ZnO as a photocatalyst, and make its final concentration 100 mg / L; (2) Place the mixture obtained in step (1) in a UVA light treatment environment for photodegradation for 60 min.

[0057] The results showed that the COD concentration in the water body decreased to 80 mg / L, the BOD concentration decreased to 22 mg / L, the ammonia nitrogen concentration decreased to 1.3 mg / L, the total phosphorus concentration decreased to 0.3 mg / L, the degradation rate of organophosphorus pesticides was 96.5%, and the degradation rate of organochlorine pesticides was 89.8%.

[0058] Table 1 Wastewater indicators under different treatment conditions

[0059] The results are shown in Table 1. Compared with the photocatalyst treatment method (Comparative Example 3), Example 1, using a multi-stage series system to treat pesticide-containing wastewater, significantly reduced the contents of COD, BOD, ammonia nitrogen, total phosphorus, organophosphorus compounds, organochlorine compounds, and aromatic compounds, with almost no impact on microbial content and no secondary pollution issues. In contrast, Comparative Example 1, using a single-stage atomization system, resulted in higher levels of organophosphorus and organochlorine compounds in the pesticide-containing wastewater, failing to effectively treat pesticide-containing wastewater containing organophosphorus and organochlorine compounds. Comparative Example 2, using an incorrect light source, also resulted in poor degradation of organophosphorus and organochlorine compounds, as well as poor degradation of aromatic compounds.

[0060] Example 5 (1) Assemble the photodegradation device according to Example 1, and connect three photodegradation devices in parallel to form a photodegradation system. The wastewater introduction system 1 of the three photodegradation devices is connected to the same inlet main pipe, and the water collection chamber 8 is connected to the same outlet main pipe. The baffle 302 of the three photodegradation devices has three layers, with apertures of 2mm, 1mm and 0.5mm from bottom to top, respectively. The light source is a UVA light source (ZW30519W-Z894, Shenzhen Anhongda Optoelectronic Technology Co., Ltd.), with a wavelength of 365nm and a light intensity of 4.8mW / cm. 2 ; (2) Take pesticide-containing wastewater (COD concentration of 1500 mg / L, BOD concentration of 600 mg / L, ammonia nitrogen concentration of 120 mg / L, total phosphorus concentration of 12 mg / L) and simultaneously pass it into the photodegradation system for three batches of parallel photodegradation treatment. The residence time of pesticide-containing wastewater in each photodegradation device is 60 min. (3) After the photodegradation system is completed, the pesticide residue is detected by a pesticide residue detector (LB-NC24 pesticide residue detector, Qingdao Lubo Jianye Environmental Protection Technology Co., Ltd.).

[0061] The results showed that the COD concentration in the water body decreased to 78 mg / L, the BOD concentration decreased to 25 mg / L, the ammonia nitrogen concentration decreased to 10 mg / L, the total phosphorus concentration decreased to 0.6 mg / L, the degradation rate of organophosphorus pesticides was 93%, and the degradation rate of organochlorine pesticides was 78%.

[0062] Table 2 Impact of Parallel Treatment on Wastewater Indicators

[0063] The results are shown in Table 2: Parallel treatment of pesticide-containing wastewater by multi-stage photodegradation devices does not affect the degradation efficiency of COD, BOD, ammonia nitrogen, total phosphorus, organophosphorus compounds, organochlorine compounds and aromatic compounds, nor does it affect the microbial content, but it significantly improves the treatment efficiency of pesticide-containing wastewater.

Claims

1. A photodegradation device for pesticide-containing wastewater, characterized in that: It includes a sewage inlet system (1) and an atomizing unit (2) connected in sequence. The bottom of the atomizing unit (2) is provided with a water collection pipe (7), which is connected to a water collection chamber (8). The atomizing unit (2) is provided with an atomizing droplet reaction chamber (3), a light source installation chamber (4) is provided on the top, and a reflection enhancement device (5) is provided on the outer wall. A circulating temperature-controlled water bath partition (6) is provided between the atomizing droplet reaction chamber (3) and the reflection enhancement device (5).

2. The photodegradation device for pesticide-containing wastewater according to claim 1, characterized in that: The atomizing droplet reaction chamber (3) is equipped with a sealing gasket (308), an RFID tag (307) and a mounting base (301) at the bottom, multiple baffles (302) inside, and a homogenizing chamber (303) at the top.

3. The photodegradation device for pesticide-containing wastewater according to claim 2, characterized in that: The baffle (302) is fixed on the baffle fixing member (3023), the baffle fixing member (3023) is fixedly connected to the fixing rope (3035), and the fixing rope (3035) is connected to the fixing hook (305) in the homogenization chamber (303); the homogenization chamber (303) is divided into upper and lower parts and connected by a quick-release flange (304); the homogenization chamber (303) contains homogenizing balls (306).

4. The photodegradation device for pesticide-containing wastewater according to claim 3, characterized in that: The baffle fixing component (3023) is provided with a baffle fixing hook (3024); the baffle (302) is composed of a baffle base (3021) and a baffle coating (3022).

5. The photodegradation device for pesticide-containing wastewater according to claim 4, characterized in that: The baffle (302) has holes of 0.2-5mm; the thickness of the baffle coating (3022) is 1.0-2.0μm, and the contact angle with water is ≤10°.

6. The photodegradation device for pesticide-containing wastewater according to claim 1, characterized in that: The bottom of the light source installation chamber (4) is provided with a first light source module (401), a second light source module (402) and a third light source module (403); the first light source module (401), the second light source module (402) and the third light source module (403) are respectively connected to the drive circuit (404); the upper part of the light source installation chamber (4) is provided with an RFID reader (405), and the top is provided with a heat sink (406) and a central control screen (407).

7. The photodegradation device for pesticide-containing wastewater according to claim 1, characterized in that: The sewage inlet system (1) consists of a pretreatment filter (103) and an inlet pipe (101) connected in sequence; a pressure regulating valve (102) is provided on the inlet pipe (101); the water collection chamber (8) includes a water storage tank (801); a valve (802) is provided on the outlet pipe of the water storage tank (801); the reflection enhancement device (5) has multiple prisms (501) embedded in it; the circulating temperature-controlled water bath partition (6) is circulatedly connected to the water storage tank (9).

8. A continuous photodegradation method for pesticide-containing wastewater, characterized in that: Includes the following steps: (1) Connect the photodegradation devices according to any one of claims 1-7 in series to form a continuous multi-stage photodegradation treatment system; (2) Pesticide-containing wastewater is fed into a multi-stage photodegradation treatment system. The atomization unit (2) and the light source installation chamber (4) are turned on to atomize the pesticide-containing wastewater into droplets of 1-100 μm and irradiate them with visible light of 240-500 mm for photodegradation. (3) The pesticide-containing wastewater stays in each stage of photodegradation treatment device for 10-60 minutes, and after purification, it is discharged from the water collection chamber (8) of the last stage device to complete the photodegradation.

9. A method for photodegradation of pesticide-containing wastewater according to claim 8, characterized in that: The multi-stage photodegradation system consists of three stages: the first stage uses UVC light with a droplet size of 50-100 μm and a visible light wavelength of 240-280 nm; the second stage uses UVA light with a droplet size of 5-15 μm and a visible light wavelength of 300-400 nm; and the third stage uses blue light with a droplet size of 1-5 μm and a visible light wavelength of 450-500 nm.

10. A rapid photodegradation method for pesticide-containing wastewater, characterized in that: Includes the following steps: (1) Connect the photodegradation devices according to any one of claims 1-7 in parallel to form a photodegradation treatment system; (2) Pesticide-containing wastewater is simultaneously introduced into the photodegradation treatment system, and the atomization unit (2) and the light source installation chamber (4) are turned on to atomize the pesticide-containing wastewater into droplets of 1-100μm and irradiate them with 240-500mm of visible light for photodegradation; (3) The pesticide-containing wastewater stays in each photodegradation treatment device for 10-60 minutes, and after purification, it is discharged from the water collection chamber (8) of each photodegradation treatment device and collected uniformly to complete the photodegradation.

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