Air flotation separation and carbon neutralization wastewater pretreatment integrated equipment

Abstract

The invention discloses air flotation separation and carbon neutralization wastewater pretreatment integrated equipment, which relates to the technical field of wastewater treatment and comprises a buffer adjusting unit and a catalytic reaction unit which are communicated along the flow direction of wastewater. Through the synergistic effect of integrated buffer adjustment, two-stage air floatation and photocatalysis, the problem that nanoscale colloids are difficult to capture in a traditional air floatation process is effectively solved while the colloid redispersion phenomenon caused by wastewater pH fluctuation is overcome. Specifically, an acid-base environment of wastewater is stabilized through a buffer mechanism of an organic acid component, abnormal changes of charges on the surface of colloid are inhibited, full-scale capture of micron-scale suspended particles and nano-scale colloid is realized by combining dual effects of micron-scale bubble adsorption and reactive oxygen free radicals generated by electrolysis, and the colloid is deeply mineralized through photocatalysis, so that the adsorption efficiency of the colloid is improved. The colloid is effectively intercepted after being oxidized and destabilized, so that the risk that the colloid is re-dispersed due to fluctuation of environmental conditions in a subsequent process is avoided, and the interception effect of the nanoscale colloid in a wastewater pretreatment process is improved.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an integrated equipment for air flotation separation and carbon neutralization wastewater pretreatment. Background Technology

[0002] In the production of polymer materials such as chemical fibers and nylon, the wastewater discharged from the spray system contains high concentrations of organic matter such as N6 (caprolactam) and N66 (adipic acid, hexamethylenediamine), and its COD (chemical oxygen demand) is usually >10,000 mg / L.

[0003] Existing wastewater pretreatment processes include dissolved air flotation (DAF). Traditional DAF relies on a single dissolved air method, namely, the venturi jet generator produces bubbles with a uniform particle size distribution. When the wastewater contains both micron-sized particles (such as caprolactam) and nano-sized colloids (such as adipic acid-hexamethylenediamine salt micelles), the single dissolved air method can only capture micron-sized particles and is unable to capture nano-sized colloids. More seriously, if there are problems such as uneven mixing of N6 and N66 wastewater or batch differences in raw materials during the production process, the pH value in the wastewater will fluctuate randomly, thereby changing the electrokinetic potential of the colloid surface and causing colloid redispersion, further weakening the DAF process's retention effect on nano-sized colloids.

[0004] The escaped nano-sized colloids are prone to forming hard scale in subsequent evaporation and concentration equipment, reducing evaporation heat transfer efficiency and forcing the evaporation and concentration equipment to enter a high-frequency shutdown and cleaning cycle. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that in the existing technology, the spray wastewater in the production process of chemical fibers and nylon contains high concentrations of organic matter, and the existing air flotation process is difficult to capture nano-sized colloids by relying on dissolved air alone. In addition, the random fluctuation of the wastewater pH causes the redispersion of nano-sized colloids, resulting in a significant reduction in the retention effect of nano-sized colloids.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an integrated equipment for air flotation separation and carbon neutralization wastewater pretreatment, comprising a buffer regulation unit and a catalytic reaction unit connected sequentially along the wastewater flow direction, wherein: The buffer regulation unit includes a flow guiding component and a gas distributor located inside the integrated tank. The flow guiding component and the gas distributor are configured to achieve pH self-regulation by utilizing the organic acid components contained in the wastewater through an acid-base balance reaction.

[0007] The catalytic reaction unit includes an air flotation tank and a photocatalytic component. The bottom of the air flotation tank is provided with a first dissolved gas release device, and the inner wall or top of the air flotation tank is provided with a second dissolved gas release device. The second dissolved gas release device includes an electrolytic electrode assembly and a catalytic coating covering the surface of the electrolytic electrode assembly.

[0008] The photocatalytic component includes a flow guide plate disposed on the inner wall of the flotation tank and a semiconductor nanotube array disposed on the surface of the flow guide plate, as well as a light source module that projects light radiation onto the semiconductor nanotube array.

[0009] The inlet pipe of the integrated tank is connected to a wastewater source, and the outlet pipe of the integrated tank is connected to the first dissolved gas release device through a pneumatic valve.

[0010] In the above technical solution, in this embodiment of the invention, after the wastewater enters the integrated tank, the flow is first forced to form a spiral upward path by rotating the guide component inside the integrated tank, thus prolonging the wastewater residence time. During the buffered flow process, organic acid components such as adipic acid in the wastewater undergo self-dissociation (HOOC(CH2)4COOH ↔ 2H⁺ + ⁻OOC(CH2)4COO⁻), and the released H⁺ neutralizes trace alkaline substances (such as residual NH3) in the wastewater to stabilize the pH value, thereby achieving pH self-regulation.

[0011] At the same time, the gas distributor generates millimeter-sized bubbles, which accelerate the neutralization reaction through gas-liquid mass transfer, quickly stabilize the pH value, and prevent deposition in low flow rate areas, thus avoiding abnormal fluctuations in local pH due to the accumulation of solid substances.

[0012] Afterwards, the adjusted wastewater is controlled by a pneumatic valve to release micron-sized air bubbles into the flotation tank through the first dissolved air release device at the bottom of the flotation tank. The surface of the air bubbles can adsorb micron-sized suspended particles (such as caprolactam particles) in the wastewater.

[0013] Next, the electrolytic electrode assembly of the second dissolved air release device is energized, causing the electrolytic electrode assembly to electrolyze water at a current density, generating hydrogen-oxygen (H2 / O2) micron-sized bubbles. The surface area and surface charge characteristics of the bubbles are suitable for capturing micron-sized pollutants. Furthermore, the active oxygen free radicals (·OH, ·O2⁻) carried on the bubble surface can directly oxidize organic matter (such as caprolactam, adipic acid, etc.) in nano-sized colloids, destroying their colloidal stability and causing them to aggregate into larger micron-sized flocs. These flocs then cooperate with the bubbles generated by the jet dissolved air device to achieve adsorption of colloids. Finally, the bubbles float to the water surface due to air flotation, forming a scum layer, achieving physical separation and completing the treatment of nano-sized colloidal pollutants that are difficult to reach by traditional air flotation.

[0014] The two-stage bubble system creates a particle size gradient coverage, ensuring the capture of pollutants of different forms across the entire scale, thereby effectively improving the COD removal rate.

[0015] Finally, the semiconductor nanotube array on the surface of the flow guide plate generates electron-hole pairs under the excitation of the light source module. The holes directly oxidize the organic molecular chains, while the electrons react with dissolved oxygen to generate superoxide radicals, thereby achieving deep mineralization of the colloid and preventing it from redispersing into nanoscale colloids due to pH or ionic strength fluctuations during the subsequent evaporation and concentration process.

[0016] The beneficial effects of this invention are: This invention overcomes the redispersion of colloids caused by pH fluctuations in wastewater by integrating buffering regulation, two-stage flotation, and photocatalysis, while effectively solving the problem of traditional flotation processes' difficulty in capturing nanoscale colloids. Specifically, the buffering mechanism of organic acid components stabilizes the acid-base environment of the wastewater, suppressing abnormal changes in the surface charge of colloids. Combined with the dual effects of micron-sized bubble adsorption and reactive oxygen free radicals generated by electrolysis, it achieves full-scale capture of micron-sized suspended particles and nanoscale colloids. Furthermore, photocatalysis deeply mineralizes the colloids, ensuring their effective retention after oxidative destabilization. This avoids the risk of redispersion of colloids due to environmental fluctuations in subsequent processes, significantly improving the retention effect of nanoscale colloids in wastewater pretreatment.

[0017] In photocatalytic reactions, electrons must combine with dissolved oxygen to generate superoxide radicals. These superoxide radicals then trigger a chain oxidation reaction, gradually degrading the organic-inorganic complex at the core of the colloidal mass into carbon dioxide, water, and inorganic salts. This achieves complete disintegration of the colloid from physical adsorption to chemical mineralization, eliminating the risk of redispersibility due to surface charge reversal caused by pH or ionic strength fluctuations during subsequent evaporation and concentration processes. This process is highly dependent on the sufficiency of dissolved oxygen. Through the synergistic design of two-stage dissolved air generation, electrolytic oxygen production, and forced aeration, the dissolved oxygen concentration in the wastewater is actively maintained, ensuring the integrity of the electron transport chain and the continuous generation of free radicals, thereby ensuring the sustainability and stability of deep mineralization of the colloid.

[0018] Furthermore, in this embodiment of the invention, the flow guiding component is a spiral baffle with turbulence holes on its surface, and the gas distributor is a microporous aeration pipe arranged around the flow guiding component, wherein the pore size of the microporous aeration pipe controls the diameter of the generated bubbles to be 1mm-3mm.

[0019] Furthermore, in this embodiment of the invention, the first dissolved gas release device is a Venturi jet injector with a working pressure of 0.25 MPa - 0.45 MPa and an output bubble diameter of 10 μm - 50 μm.

[0020] Furthermore, in this embodiment of the invention, the electrolytic electrode assembly is composed of parallel titanium-based porous plates, the spacing between the titanium-based porous plates is controlled at 10mm-20mm, and the catalytic coating on the surface of the titanium-based porous plates contains a composite oxide of iridium dioxide and tantalum pentoxide.

[0021] Furthermore, in this embodiment of the invention, the guide plates are alternately stacked in a spaced-out manner to form an "S"-shaped wastewater rising channel.

[0022] Furthermore, in this embodiment of the invention, the light source module is an ultraviolet lamp assembly arranged on the inner wall of the flotation tank and / or at the top opening of the flotation tank.

[0023] Furthermore, in this embodiment of the invention, the semiconductor nanotube array is nitrogen-doped titanium dioxide nanotubes grown vertically on the surface of the flow guide plate. Each nanotube is hollow cylindrical with a diameter of 40nm-60nm and a length of 0.8μm-1.2μm.

[0024] Furthermore, in this embodiment of the invention, the surface of the semiconductor nanotube array is modified with fluorosilane to form a superhydrophobic interface with a static water contact angle >150°.

[0025] Furthermore, in this embodiment of the invention, the integrated air flotation separation and carbon neutralization wastewater pretreatment equipment further includes a control system. The control system includes a pH sensor and a COD sensor disposed in the air flotation tank. The pH sensor is configured to detect the pH data of the wastewater in the air flotation tank, and the COD sensor is configured to detect the COD data of the wastewater in the air flotation tank.

[0026] Furthermore, in this embodiment of the invention, the current density of the electrolysis electrode assembly is adjusted based on the detected wastewater pH data. The light intensity of the light source module is adjusted based on the detected wastewater COD data. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of an integrated air flotation separation and carbon neutralization wastewater pretreatment device according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram illustrating the detection of staged changes in wastewater pH and COD in an embodiment of the present invention.

[0029] 1. Integrated tank, 2. Flotation tank, 3. Flow guiding component, 4. Gas distributor, 5. First dissolved gas release device, 6. Second dissolved gas release device, 7. Light source module, 8. Flow guide plate. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clear and complete, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some, not all, embodiments of the present invention, and are merely illustrative of the embodiments of the present invention. They are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "center," "middle," "upper," "lower," "left," "right," "inner," "outer," "top," "bottom," "side," "vertical," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "a," "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] For purposes of simplicity and illustration, the principles of the embodiments are described primarily by way of example. In the following description, numerous specific details are set forth to provide a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that these embodiments may not be limited to these specific details in practice. In some instances, well-known principles applied to their structures have not been described in detail to avoid unnecessarily obscuring these embodiments. Furthermore, all embodiments can be used in combination with each other. Example

[0034] It should be noted that the accompanying drawings are part of the content of the instruction manual. The structural shapes, connections, fits, and positional relationships that can be clearly seen in the accompanying drawings should all be understood as part of the content of the instruction manual.

[0035] An integrated equipment for air flotation separation and carbon neutralization wastewater pretreatment, such as Figure 1As shown, it includes a buffer regulation unit and a catalytic reaction unit connected sequentially along the wastewater flow direction, wherein: The buffer regulation unit includes a flow guide 3 and a gas distributor 4 installed in the integrated tank 1. The flow guide 3 and the gas distributor 4 are configured to achieve pH self-regulation by utilizing the organic acid components contained in the wastewater through an acid-base balance reaction.

[0036] The catalytic reaction unit includes an air flotation tank 2 and a photocatalytic component. The bottom of the air flotation tank 2 is provided with a first dissolved gas release device 5, and the inner wall or top of the air flotation tank 2 is provided with a second dissolved gas release device 6. The second dissolved gas release device 6 includes an electrolytic electrode assembly and a catalytic coating covering the surface of the electrolytic electrode assembly.

[0037] The photocatalytic component includes a flow guide plate 8 disposed on the inner wall of the flotation tank 2 and a semiconductor nanotube array disposed on the surface of the flow guide plate 8, as well as a light source module 7 that projects light radiation onto the semiconductor nanotube array.

[0038] The inlet pipe of the integrated tank 1 is connected to the wastewater source, and the outlet pipe of the integrated tank 1 is connected to the first dissolved gas release device 5 through a pneumatic valve.

[0039] The phased changes in wastewater pH and COD are as follows: Figure 2 As shown, after the mixed wastewater (N6, N66) enters the integrated tank 1, the design conditions are: flow rate 500 kg / h. Taking the average value of the two wastewater mixtures, the actual test results during the initial fluctuation period of the water quality are as follows: Buffer adjustment period: After the wastewater enters the integrated tank 1, the flow is forced to form a spiral upward path by rotating the guide component 3 inside the integrated tank 1, thus prolonging the wastewater residence time. During the buffer flow process, organic acid components such as adipic acid in the wastewater undergo self-dissociation (HOOC(CH2)4COOH ↔ 2H⁺ + ⁻OOC(CH2)4COO⁻), and the released H⁺ neutralizes the trace alkaline substances (such as residual NH3) in the wastewater to stabilize the pH value, thereby achieving pH self-regulation.

[0040] Meanwhile, the gas distributor 4 generates millimeter-sized bubbles, which accelerate the neutralization reaction through gas-liquid mass transfer, quickly stabilize the pH value, and prevent deposition in low flow rate areas, thus avoiding abnormal fluctuations in local pH due to the accumulation of solid substances.

[0041] Stabilization period: After adjustment, the wastewater is controlled by a pneumatic valve to release micron-sized bubbles into the flotation tank 2 through the first dissolved air release device 5 at the bottom of the flotation tank 2. The surface of the bubbles can adsorb micron-sized suspended particles (such as caprolactam particles) in the wastewater.

[0042] Next, the electrolytic electrode assembly of the second dissolved air release device 6 is energized, causing the electrolytic electrode assembly to electrolyze water at a current density, generating hydrogen-oxygen (H2 / O2) micron-sized bubbles. The surface area and surface charge characteristics of the bubbles are suitable for capturing micron-sized pollutants. Furthermore, the active oxygen free radicals (·OH, ·O2⁻) carried on the bubble surface can directly oxidize organic matter (such as caprolactam, adipic acid, etc.) in nano-sized colloids, destroying their colloidal stability and causing them to aggregate into larger micron-sized flocs. These flocs then cooperate with the bubbles generated by the jet dissolved air device to achieve adsorption of colloids. Finally, the bubbles float to the water surface due to air flotation to form a scum layer, achieving physical separation and completing the treatment of nano-sized colloidal pollutants that are difficult to reach by traditional air flotation.

[0043] The two-stage bubble system creates a particle size gradient coverage, ensuring the capture of pollutants of different forms across the entire scale, thereby effectively improving the COD removal rate.

[0044] Finally, the semiconductor nanotube array on the surface of the guide plate 8 generates electron-hole pairs under the excitation of the light source module 7. The holes directly oxidize the organic molecular chains, while the electrons react with dissolved oxygen to generate superoxide radicals, thereby achieving deep mineralization of the colloid and preventing it from redispersing into nanoscale colloids due to pH or ionic strength fluctuations during the subsequent evaporation and concentration process.

[0045] The aforementioned flow guiding component 3 is driven to rotate by a motor, and the aforementioned gas distributor 4 is connected to an air pump to achieve aeration. The aforementioned first dissolved gas release device 5 is connected to an air compressor pump to mix with wastewater and release micron-sized bubbles, and the aforementioned electrolysis electrode assembly is connected to a power source to achieve energization. Since these are common technical solutions and structural choices in the field, those skilled in the art can understand them without creative effort, and therefore will not be explained in detail.

[0046] The advantages of this invention lie in its synergistic effect of integrating buffer regulation, two-stage flotation, and photocatalysis. This overcomes the redispersion of colloids caused by pH fluctuations in wastewater while effectively solving the problem of capturing nanoscale colloids in traditional flotation processes. Specifically, the organic acid component stabilizes the acid-base environment of the wastewater through a buffering mechanism, suppressing abnormal changes in the surface charge of colloids. Combined with the dual effects of micron-sized bubble adsorption and reactive oxygen free radicals generated by electrolysis, it achieves full-scale capture of micron-sized suspended particles and nanoscale colloids. Furthermore, photocatalysis deeply mineralizes the colloids, ensuring their effective retention after oxidative destabilization. This avoids the risk of redispersion of colloids due to environmental fluctuations in subsequent processes, significantly improving the retention effect of nanoscale colloids in wastewater pretreatment.

[0047] Furthermore, in the photocatalytic reaction, electrons must combine with dissolved oxygen to generate superoxide radicals. These superoxide radicals then trigger a chain oxidation reaction, gradually degrading the organic-inorganic complex at the core of the colloidal mass into carbon dioxide, water, and inorganic salts. This achieves the complete disintegration of the colloid from physical adsorption to chemical mineralization, thereby eliminating the risk of redispersibility due to surface charge reversal caused by pH or ionic strength fluctuations during subsequent evaporation and concentration processes. This process is highly dependent on the sufficiency of dissolved oxygen. Through the synergistic design of two-stage dissolved air generation, electrolytic oxygen production, and forced aeration, the dissolved oxygen concentration in the wastewater is actively maintained, ensuring the integrity of the electron transport chain and the continuous generation of free radicals, thus ensuring the sustainability and stability of the deep mineralization of the colloid.

[0048] Specifically, the flow guide plate has a corrugated structure, and the bottom region of the corrugations is densely packed with semiconductor nanotube arrays.

[0049] Another advantage of this invention is that, during wastewater treatment, the troughs of the ripples easily create a blocking effect, temporarily trapping nanoscale colloids and forcing them to collide secondary with micron-sized bubbles, thus improving the trapping effect. Furthermore, the high-density semiconductor nanotube array in the trough region forms a locally high-concentration reactive oxygen species (ROS) region under ultraviolet light excitation, whose surface catalytic activity is significantly higher than that of the low-density region at the ripple peaks. This catalytic activity gradient induces selective oxidation reactions on the colloid surface. According to the redox-mediated migration principle, the colloids migrate and aggregate towards the highly active region. During this process, the colloids disintegrate due to continuous attack by ROS, and then their aggregated size increases to the micron level, increasing the probability of bubble capture.

[0050] Specifically, the flow guiding component 3 is a spiral baffle with perforations on its surface, and the gas distributor 4 is a microporous aeration tube surrounding the flow guiding component 3. The pore size of the microporous aeration tube controls the diameter of the generated bubbles to be 1mm-3mm. The combined design of the spiral baffle and the microporous aeration tube enhances the mass transfer efficiency of organic acid dissociation products in wastewater. By forcibly swirling and microbubble disturbance, the acid-base neutralization reaction is accelerated, avoiding the destruction of colloidal stability caused by sudden changes in local pH value. At the same time, the perforation design prevents suspended solids from depositing in low-velocity areas, ensuring a continuous and stable buffering and regulation process.

[0051] Specifically, the first dissolved gas release device 5 is a Venturi jet generator with an operating pressure of 0.25 MPa - 0.45 MPa and an output bubble diameter of 10 μm - 50 μm. The Venturi jet generator generates 10-50 μm micron-sized bubbles within a specific pressure range. The surface energy of these bubbles matches the adsorption energy barrier of micron-sized particles, and the collision probability between the bubbles and particles is enhanced through turbulent shearing.

[0052] More specifically, the electrolytic electrode assembly consists of parallel titanium-based porous plates, with the spacing between the plates controlled at 10mm-20mm. The catalytic coating on the surface of the titanium-based porous plates contains a composite oxide of iridium dioxide and tantalum pentoxide. During electrolysis, not only are micron-sized bubbles generated, but also reactive oxygen free radicals are produced in situ. These active substances directly attack the functional groups on the surface of the nanocolloids, disrupting their electric double-layer structure and compensating for the inadequacy of a single physical adsorption mechanism in treating nanoscale pollutants.

[0053] Specifically, the guide plates 8 are arranged in alternating layers at intervals, and the 55° inclined layering of the guide plates forms an "S"-shaped wastewater rising channel. This causes periodic velocity gradient changes in the wastewater during its ascent, forcing colloidal particles and bubbles to come into multiple contacts with the photocatalyst, significantly increasing the capture probability of nanoscale colloids within the limited reaction space.

[0054] More specifically, the light source module 7 is an ultraviolet lamp group arranged on the inner wall of the flotation tank 2 and / or the opening at the top of the flotation tank 2, with an emission wavelength of 365nm±5nm and a light intensity of 60mW / cm².

[0055] More specifically, the semiconductor nanotube array consists of nitrogen-doped titanium dioxide nanotubes grown vertically on the surface of the flow guide plate 8. Each nanotube is a hollow cylinder with a diameter of 40nm-60nm and a length of 0.8μm-1.2μm.

[0056] More specifically, the surface of the semiconductor nanotube array is modified with fluorosilane to form a superhydrophobic interface with a static water contact angle >150°. The fluorosilane superhydrophobic modification of the semiconductor nanotube surface forms a superhydrophobic interface, or gas film layer, which reduces the adhesion and retention of pollutants at the catalytic interface, while enhancing the diffuse reflection intensity of ultraviolet light.

[0057] Specifically, the integrated air flotation separation and carbon neutralization wastewater pretreatment equipment also includes a control system. The control system includes a pH sensor and a COD sensor installed in the air flotation tank 2. The pH sensor is configured to detect the pH data of the wastewater in the air flotation tank 2, and the COD sensor is configured to detect the COD data of the wastewater in the air flotation tank 2.

[0058] More specifically, the control system executes the following control logic: When the pH sensor reading is lower than the threshold corresponding to the electrochemical potential of nano-colloids, the current density of the electrolysis electrode assembly is dynamically increased according to the pH deviation to enhance the generation of reactive oxygen species. For example, when the pH of the effluent from the integrated tank 1 is detected to be <4.0, the current density of the electrolysis electrode assembly is adjusted to 35 mA / cm², and the hydrogen / oxygen generated by water electrolysis helps to raise the pH, ensuring stable operation during the stable treatment period.

[0059] When the COD sensor detects a value exceeding a preset threshold, the ultraviolet light intensity of the light source module 7 is increased according to the pollutant load gradient to stimulate a free radical chain reaction. For example, when the COD concentration in the effluent of the flotation tank 2 is detected to be >2000 mg / L, it indicates that a large number of uncaptured nano-sized colloids remain in the wastewater. Therefore, the ultraviolet band of the light source module 7 needs to be increased to 80 mW / cm²-120 mW / cm² to enhance the electron-hole pair separation efficiency and significantly increase the generation rate of hydroxyl radicals (·OH) and superoxide radicals (·O⁻). These reactive oxygen species can non-selectively attack the functional groups on the surface of colloids, destroying their double-layer stability: ·OH attacks the organic-inorganic hybrid bonds in the core of the colloid, while ·O⁻ neutralizes the surface charge and reduces the electrokinetic potential, ultimately decomposing the colloid into carbon dioxide, water, and settleable inorganic salts, achieving a complete transformation from physical adsorption stabilization to chemical bond breaking and mineralization.

[0060] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, the invention is not limited to the scope of the specific embodiments. For those skilled in the art, all inventions utilizing the concept of the present invention are protected as long as various variations are within the spirit and scope of the invention as defined and determined by the appended claims.

Claims

1. An air floatation separation and carbon neutral wastewater pretreatment integrated device, characterized in that, The device comprises a buffer adjustment unit and a catalytic reaction unit connected in sequence along the wastewater flow direction. The buffer adjustment unit comprises a flow guide member and a gas distributor arranged in the integrated tank, which are configured to realize pH self-regulation through acid-base balance reaction of organic acid components contained in the wastewater. The catalytic reaction unit comprises a gas floatation tank and a photocatalytic assembly, the bottom of the gas floatation tank is provided with a first dissolved gas releasing device, the inner wall or top of the gas floatation tank is provided with a second dissolved gas releasing device comprising an electrolytic electrode group and a catalytic coating covering the surface of the electrolytic electrode group. The photocatalytic assembly comprises a flow guide plate arranged on the inner wall of the gas floatation tank and a semiconductor nanotube array arranged on the surface of the flow guide plate, and a light source module for projecting light radiation to the semiconductor nanotube array. The water inlet pipe of the integrated tank is connected to a wastewater source, and the water outlet pipe of the integrated tank is connected to the first dissolved gas releasing device through a pneumatic valve.

2. The air floatation separation and carbon neutralization wastewater pretreatment integrated device according to claim 1, characterized in that, The flow guide member is a helical baffle with turbulence holes on the surface, and the gas distributor is a microporous aeration pipe arranged around the flow guide member, the pore size of which is controlled to produce bubbles with a diameter of 1mm-3mm.

3. The air floatation separation and carbon neutralization wastewater pretreatment integrated device according to claim 1, characterized in that, The first dissolved gas releasing device is a Venturi jet, the working pressure of which is 0.25 MPa-0.45 MPa, and the output bubble diameter is 10μm-50μm.

4. The apparatus according to claim 3, wherein The electrolytic electrode group is composed of titanium-based porous plates arranged in parallel, the spacing between the titanium-based porous plates is controlled to be 10mm-20mm, and the catalytic coating on the surface of the titanium-based porous plates comprises a composite oxide of iridium dioxide and tantalum pentoxide.

5. The air floatation separation and carbon neutralization wastewater pretreatment integrated device according to claim 1, characterized in that, The flow guide plates are alternately stacked in a spaced arrangement to form an "S" shaped wastewater rising channel.

6. The air floatation separation and carbon neutralization wastewater pretreatment integrated device according to claim 5, characterized in that, The light source module is a group of ultraviolet lamps arranged on the inner wall of the gas floatation tank and / or the opening of the top of the gas floatation tank.

7. The air floatation separation and carbon neutralization wastewater pretreatment integrated device according to claim 5, characterized in that, The semiconductor nanotube array is nitrogen-doped titanium dioxide nanotubes vertically grown on the surface of the flow guide plate, a single nanotube is in the form of a hollow cylinder, the tube diameter is 40nm-60nm, and the length is 0.8μm-1.2μm.

8. The air floatation separation and carbon neutralization wastewater pretreatment integrated device according to claim 7, characterized in that, The surface of the semiconductor nanotube array is modified by fluorosilane to form a super-hydrophobic interface with a static water contact angle >150°.

9. The air floatation separation and carbon neutralization wastewater pretreatment integrated device according to claim 6, characterized in that, The control system comprises a pH sensor and a COD sensor arranged in the gas floatation tank, the pH sensor is configured to detect the pH data of the wastewater in the gas floatation tank, and the COD sensor is configured to detect the COD data of the wastewater in the gas floatation tank.

10. The apparatus according to claim 9, wherein the apparatus is characterized by: The current density of the electrolytic electrode group is adjusted according to the detected pH data of the wastewater, and the light intensity of the light source module is adjusted according to the detected COD data of the wastewater.

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