Device for treating organic wastewater through electro-catalysis

Abstract

The invention relates to the technical field of wastewater treatment, in particular to an electrocatalytic organic wastewater treatment device which comprises a tank body, an outer barrel and an inner barrel, the outer barrel and the inner barrel are arranged in the tank body, the inner barrel is arranged in the outer barrel, a first reaction area is arranged in the inner barrel, a second reaction area is formed between the inner barrel and the outer barrel, and a third reaction area is formed between the outer barrel and the tank body. A communicating hole is formed in the inner barrel and is communicated with the first reaction area and the second reaction area, and an overflow hole is formed in the outer barrel; a feeding assembly is arranged in the first reaction area, polytetrafluoroethylene balls are arranged in the second reaction area, and a waste treatment assembly is arranged in the third reaction area. Meanwhile, non-free-radical active species such as singlet oxygen generated by air on the surfaces of an electric field, ultrasonic waves and a polytetrafluoroethylene material are combined to form a double-effect oxidation system under the combined action of free radicals and non-free radicals, so that the degradation efficiency of organic pollutants is remarkably improved, and the application range of the organic pollutants is remarkably widened.

Description

An electrocatalytic device for treating organic wastewater Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an electrocatalytic device for treating organic wastewater. Background Technology

[0002] Organic wastewater refers to industrial or domestic wastewater primarily composed of organic pollutants. Its chemical oxygen demand (COD) typically exceeds 2000 mg / L (high-concentration organic wastewater can exceed 3000 mg / L), mainly originating from industries such as papermaking, leather, and food processing. Pollutants include organic matter such as carbohydrates, proteins, and oils. Direct discharge can easily lead to eutrophication of water bodies, depletion of dissolved oxygen, and release of harmful gases.

[0003] The main treatment methods for organic wastewater usually combine physical, chemical and biological technologies, and are applied in combination according to the wastewater concentration, composition and degradation difficulty: (1) Physical method. Separate or remove pollutants through physical action, such as filtration, sedimentation, flotation and adsorption. Suitable for removing suspended solids or precipitates in the pretreatment stage, economical and efficient but with low organic matter removal rate. (2) Chemical method. Utilize chemical reactions to degrade organic matter, such as oxidation, neutralization or precipitation. Highly efficient and fast, but costly, suitable for difficult-to-degrade or toxic wastewater. Specific technologies: Oxidation method: Fenton reagent catalyzes the oxidation and decomposition of organic matter, especially effective for high-concentration wastewater. Incineration method: Direct high-temperature combustion for high-concentration organic wastewater to achieve thorough treatment; secondary pollution can be reduced by injecting into the furnace through atomizing nozzles. Wet oxidation: Catalyzes the degradation of difficult-to-treat organic matter under high temperature and pressure. (3) Biological method. Rely on microbial metabolism to decompose organic matter, low cost and sustainable, but sensitive to difficult-to-degrade substances or shock loads.

[0004] Common treatment methods often involve multiple combinations, such as physical, chemical, and biological methods, to achieve better results. Physicochemical pretreatment and anaerobic-aerobic combined processes can significantly reduce COD.

[0005] Electrocatalytic advanced oxidation technology is a highly efficient method for treating organic wastewater. It generates or activates oxidants through an electric field, producing highly oxidizing free radicals (such as sulfate radicals and hydroxyl radicals) that degrade organic pollutants. Currently, persulfate-activated electrocatalytic technology has received widespread attention, with ferrous ion activation of persulfate being a common method. However, traditional electrocatalytic devices often suffer from the following problems: most devices rely on free radical oxidation, resulting in insufficient degradation efficiency for certain recalcitrant organic compounds; free radicals are easily quenched by water quality interference; the oxidation pathway is singular, leading to limited degradation efficiency; to achieve ideal treatment results, excessive persulfate is often required, increasing treatment costs; and reaction products and intermediates are not properly treated: the degradation process may produce toxic intermediates or metal ion precipitates, which, if not further treated, may cause secondary pollution. Summary of the Invention

[0006] The technical problem to be solved by this invention is: in order to overcome the problems that most existing devices rely on free radical oxidation, which has insufficient degradation efficiency for some recalcitrant organic matter, and that free radicals are easily quenched by water quality interference, resulting in a single oxidation pathway and limited degradation efficiency; and that excessive persulfate is often required to achieve the desired treatment effect, which increases the treatment cost, this invention provides an electrocatalytic treatment device for organic wastewater.

[0007] The technical solution adopted by this invention to solve its technical problem is as follows: an electrocatalytic treatment device for organic wastewater includes a tank and an outer tank and an inner tank arranged inside the tank. The inner tank is arranged inside the outer tank and has a first reaction zone. A second reaction zone is formed between the inner tank and the outer tank, and a third reaction zone is formed between the outer tank and the tank. A connecting hole is provided on the inner tank, connecting the first and second reaction zones. An overflow hole is provided on the outer tank, connecting the second and third reaction zones. A liquid outlet hole is provided at the bottom of the tank. A feeding component is arranged in the first reaction zone to input air, sulfate solution, and wastewater to be treated into the first reaction zone. Polytetrafluoroethylene (PTFE) microspheres are arranged in the second reaction zone to react with water to produce active free radicals. A waste treatment component is arranged in the third reaction zone to treat wastewater. The reaction products are fed to the negative terminal of the power supply, while the inner tank is connected to the positive terminal. The inner tank generates ferrous ions. The device electrochemically activates persulfate to generate sulfate radicals. Simultaneously, it combines with non-radical reactive species such as singlet oxygen generated by air (oxygen) in an electric field, ultrasound, and on the surface of polytetrafluoroethylene (PTFE) material. This forms a dual-effect oxidation system with the combined action of free radicals and non-free radicals, broadening the oxidation pathway and significantly improving the degradation efficiency and applicability of organic pollutants. Utilizing the hydrophobicity of PTFE microspheres, hydrophobic organic matter can be adsorbed and enriched on its surface. Under the action of ultrasound, the friction at the PTFE-water interface intensifies, which not only promotes the transfer of electrons at the interface to generate hydroxyl radicals, but also facilitates the adsorption and activation of oxygen on its surface, generating more reactive oxygen species. This achieves efficient enrichment and degradation of pollutants at the reaction interface.

[0008] To address the issue of how to efficiently and uniformly introduce air, wastewater, and reagents into the first reaction zone to ensure the full progress of the initial reaction, a feeding assembly is further included, comprising an air supply pipe, a waste liquid pipe, a dosing pipe, and a diffusion pipe. The diffusion pipe extends into the inner tank, and a number of diffusion holes are spaced apart along its extension direction. The output end of the air supply pipe is connected to the input end of the diffusion pipe, the output end of the waste liquid pipe is connected to the air supply pipe, and the output end of the dosing pipe is connected to the waste liquid pipe.

[0009] To address the issue of how to enhance the electric field distribution within the first reaction zone and further improve the efficiency of the electrochemical reaction, a further step is to make the diffuser material metal and connect the diffuser to the negative terminal of the power supply.

[0010] Furthermore, the outer tub is made of stainless steel, and the inner tub is made of iron.

[0011] To address the issue of ensuring stable and sufficient flow of wastewater along the designed path between reaction zones and avoiding short-circuiting, the design further includes a connecting hole located at the bottom of the inner tank and an overflow hole located at the top of the outer tank.

[0012] To address the challenge of further enhancing the interfacial interaction between the PTFE microspheres and water in the second reaction zone to maximize their catalytic and oxygen-activating capabilities, an ultrasonic generator is installed on the outer casing to increase the interfacial friction between the PTFE microspheres and water.

[0013] To address the issue of how to deeply treat byproducts (such as metal ions and trace organic matter) generated in the preceding oxidation stage, prevent secondary pollution, and ensure the safety of the final effluent, a waste treatment component is further included, comprising iron packing material and adsorption packing material, which are filled in the third reaction zone.

[0014] The second reaction zone is further equipped with a sieve for accommodating polytetrafluoroethylene (PTFE) microspheres, which are arranged within the sieve.

[0015] The beneficial effects of this invention are as follows: The electrocatalytic treatment device for organic wastewater provided by this invention generates sulfate radicals by electrochemically activating persulfate. Simultaneously, it combines this with non-radical reactive species such as singlet oxygen generated by air (oxygen) in an electric field, ultrasound, and on the surface of polytetrafluoroethylene (PTFE) material, forming a dual-effect oxidation system where free radicals and non-radicals work together. This broadens the oxidation pathway and significantly improves the degradation efficiency and applicability of organic pollutants. Utilizing the hydrophobicity of PTFE microspheres, hydrophobic organic matter can be adsorbed and enriched on their surface. Under the action of ultrasound, the friction at the PTFE-water interface intensifies, promoting not only the transfer of interfacial electrons to generate hydroxyl groups... The presence of free radicals and other reactive oxygen species facilitates the adsorption and activation of oxygen on the surface, generating more reactive oxygen species and achieving efficient enrichment and degradation of pollutants at the reaction interface. The device integrates "electro-corrosion activation (first reaction zone) - heterogeneous catalytic oxidation (second reaction zone) - deep product treatment (third reaction zone)" into one unit. The first reaction zone is mainly based on ferrous ion electrochemical activation; the second reaction zone is mainly based on PTFE microspheres and ultrasonic synergistic catalytic oxidation; the third reaction zone removes residual organic matter, reduces some metal ions and retains solid particles through multiple actions such as adsorption, reduction and filtration of iron packing and adsorption packing, realizing continuous treatment and post-treatment and avoiding secondary pollution. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 is a schematic diagram of the structure of the present invention; Figure 2 is a schematic diagram of another embodiment of the present invention.

[0018] In the diagram: 1. Tank body, 11. Liquid outlet, 2. Outer tank, 21. Overflow hole, 3. Inner tank, 31. Connecting hole, 4. First reaction zone, 5. Second reaction zone, 51. PTFE balls, 52. Screen, 6. Third reaction zone, 7. Feeding assembly, 71. Gas supply pipe, 72. Waste liquid pipe, 73. Dosing pipe, 74. Diffuser pipe, 741. Diffuser hole, 8. Waste treatment assembly, 81. Iron packing, 82. Adsorption packing, 9. Ultrasonic generator. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0020] Figure 1 is a schematic diagram of the structure of the present invention. An electrocatalytic treatment device for organic wastewater includes a tank 1 and an outer tank 2 and an inner tank 3 arranged within the tank 1. The inner tank 3 is arranged inside the outer tank 2 and has a first reaction zone 4. A second reaction zone 5 is formed between the inner tank 3 and the outer tank 2, and a third reaction zone 6 is formed between the outer tank 2 and the tank 1. A connecting hole 31 is provided on the inner tank 3, connecting the first reaction zone 4 and the second reaction zone 5. An overflow hole 21 is provided on the outer tank 2, connecting the second reaction zone 5 and the third reaction zone 6. A liquid outlet hole 11 is provided at the lower part of the tank 1. A feeding assembly 7 is arranged in the first reaction zone 4, used to input air into the first reaction zone 4. The system consists of gas, sulfate solution, and wastewater to be treated. The second reaction zone 5 contains polytetrafluoroethylene (PTFE) spheres 51, which react with water to produce active free radicals. The third reaction zone 6 contains a waste treatment component 8, which treats the reaction products. The feeding component 7 and the outer tank 2 are connected to the negative terminal of the power supply, while the inner tank 3 is connected to the positive terminal. The inner tank 3 can generate ferrous ions. Through the three series-connected reaction zones formed by the tank 1, outer tank 2, and inner tank 3, combined with specific electrode connections and functional area arrangements (feeding, catalysis, and post-treatment), a complete, continuous, and efficient integrated treatment system is constructed, from primary activation oxidation of pollutants to deep catalytic oxidation and then to safe product treatment.

[0021] The feeding assembly 7 includes an air supply pipe 71, a waste liquid pipe 72, a dosing pipe 73, and a diffusion pipe 74. The diffusion pipe 74 extends into the inner tank 3, and a plurality of diffusion holes 741 are spaced apart along its extension direction. The output end of the air supply pipe 71 is connected to the input end of the diffusion pipe 74, the output end of the waste liquid pipe 72 is connected to the air supply pipe 71, and the output end of the dosing pipe 73 is connected to the waste liquid pipe 72. Through the air supply pipe 71, the waste liquid pipe 72, the dosing pipe 73, and the diffusion pipe 74 with diffusion holes 741, the premixing and uniform distribution of gas, liquid, and drug are achieved, enhancing the mass transfer efficiency and laying the foundation for the uniform and efficient generation of active species in the first reaction zone 4.

[0022] The diffuser tube 74 is made of metal and is connected to the negative terminal of the power supply. Connecting the metal diffuser tube 74 to the negative terminal of the power supply makes it part of the cathode, which expands the effective area of ​​the cathode, optimizes the electric field distribution in the first reaction zone, promotes electrode reactions (such as oxygen reduction reaction) and electro-corrosion of the inner barrel anode, thereby improving the generation efficiency of active species.

[0023] The outer barrel 2 is made of stainless steel, and the inner barrel 3 is made of iron. The inner barrel 3 uses iron as the anode to ensure that it can continuously and stably electrolytically release Fe²⁺ to activate persulfate. The outer barrel 2 uses stainless steel as the cathode, which has good conductivity, corrosion resistance and structural strength, ensuring the long-term stable operation of the device.

[0024] The connecting hole 31 is located at the bottom of the inner tank 3, and the overflow hole 21 is located at the top of the outer tank 2. Placing the connecting hole 31 at the bottom allows wastewater to enter the second reaction zone 5 from the bottom of the first reaction zone 4, ensuring sufficient residence time in the first reaction zone 4. Placing the overflow hole 21 at the top forces the wastewater to overflow from the top into the third reaction zone 6 after filling the second reaction zone 5, ensuring full contact between the wastewater and the PTFE balls and optimizing the hydraulic residence time distribution.

[0025] An ultrasonic generator 9 is installed on the outer barrel 2. The ultrasonic generator 9 is used to increase the interfacial friction between the polytetrafluoroethylene microspheres 51 and water. By installing the ultrasonic generator 9, the cavitation effect and mechanical vibration of the ultrasonic waves are used to violently disturb the PTFE-water interface, which greatly increases the interfacial friction and contact area. This not only strengthens the process of interfacial electron transfer to generate free radicals, but also greatly promotes the adsorption and activation of oxygen on the PTFE surface, significantly enhancing the contribution of non-free radical oxidation pathways.

[0026] In Figure 1, the tank 1, outer barrel 2, and inner barrel 3 of this application are arranged coaxially, while in Figure 2, the tank 1, outer barrel 2, and inner barrel 3 of this application are arranged off-axis.

[0027] The waste treatment component 8 includes an iron packing material 81 and an adsorption packing material 82, which are filled in the third reaction zone 6. The iron packing material 81 can be made of iron shavings. Through micro-electrolysis and chemical reduction, the iron packing material 81 can remove residual oxidants and reduce and precipitate some metal ions. The adsorption packing material 82 can deeply remove trace organic pollutants and color from the water through strong physical adsorption and partial catalysis. The combination of the two constitutes an efficient and economical terminal protection unit. The adsorption packing material 82 can be made of activated carbon.

[0028] The second reaction zone 5 is equipped with a sieve 52 for containing polytetrafluoroethylene (PTFE) balls 51, which are arranged inside the sieve 52.

[0029] Working process: Power is turned on and the material is fed in. A DC voltage of 30-50V is applied between the two poles of the power supply. The wastewater and persulfate solution to be treated are fed into the air supply pipe 71 through the dosing pipe 73 and the waste liquid pipe 72. After mixing with air, they enter the metal diffusion pipe 74 that extends to the inner tank 3.

[0030] First Reaction Zone 4 (Electrochemical Activation and Primary Oxidation): The mixed fluid flows uniformly from the diffusion holes of diffuser 74 into the first reaction zone 4. The inner tank 3 (anode, made of iron) undergoes electrochemical corrosion under the influence of the electric field, continuously releasing ferrous ions (Fe²⁺). These ferrous ions activate persulfate (S₂O₈²⁻), generating highly oxidizing sulfate radicals (SO₄·⁻). Simultaneously, oxygen from the blown-in air can be partially converted into singlet oxygen (¹O₂) and other reactive species under the electric field and solution conditions. Organic pollutants in the wastewater are subjected to a combined attack from free radicals (SO₄·⁻) and non-free radicals (such as ¹O₂) in this zone, resulting in initial oxidative degradation.

[0031] Second Reaction Zone 5 (Heterogeneous Catalytic Oxidation): The pre-treated wastewater enters the second reaction zone 5 through the connecting hole located at the bottom of the inner tank. This zone is filled with polytetrafluoroethylene (PTFE) microspheres 51 and is subjected to the action of an ultrasonic generator. The ultrasound enhances the interfacial friction and cavitation effect between the PTFE microspheres and water, on the one hand promoting the interfacial electron transfer to induce the generation of hydroxyl radicals (·OH) and superoxide radicals (·O2⁻), and on the other hand causing the PTFE surface to generate static electricity due to friction. Combined with its hydrophobic properties, it strongly adsorbs oxygen and hydrophobic organic matter, and efficiently generates negative oxygen ions and singlet oxygen at the interface, thus carrying out deep catalytic oxidation of organic matter.

[0032] Third Reaction Zone 6 (Deep Treatment and Effluent): The deep-oxidized wastewater flows into the third reaction zone 6 through the overflow hole 21 located at the top of the outer tank 2. This zone is filled with iron packing material 81 and adsorption packing material 82. The outer tank 2 acts as the cathode, where some of the iron ions (Fe³⁺) that migrate there are reduced and deposited. The iron packing material 81 further removes residual oxidants and reduces some heavy metal ions through micro-electrolysis and reduction. The adsorption packing material 82 performs adsorption and filtration functions, capturing trace amounts of incompletely degraded organic matter and suspended particles. Finally, the treated clean water that meets the standards is discharged from the outlet hole 11 at the bottom of the tank 1.

[0033] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An electrocatalytic treatment device for organic wastewater, characterized in that, The tank includes a tank body (1) and an outer barrel (2) and an inner barrel (3) arranged inside the tank body (1). The inner barrel (3) is arranged inside the outer barrel (2). The inner barrel (3) has a first reaction zone (4). A second reaction zone (5) is formed between the inner barrel (3) and the outer barrel (2). A third reaction zone (6) is formed between the outer barrel (2) and the tank body (1). A connecting hole (31) is provided on the inner barrel (3), which connects the first reaction zone (4) and the second reaction zone (5). An overflow hole (21) is provided on the outer barrel (2), which connects the second reaction zone (5) and the third reaction zone (6). The tank body (1) The lower part is provided with a liquid outlet (11); a feeding component (7) is arranged in the first reaction zone (4), the feeding component (7) is used to input air, sulfate solution and wastewater to be treated into the first reaction zone (4); a polytetrafluoroethylene ball (51) is arranged in the second reaction zone (5), the polytetrafluoroethylene ball (51) is used to react with water to produce active free radicals; a waste treatment component (8) is arranged in the third reaction zone (6), the waste treatment component (8) is used to treat the reaction products; the feeding component (7) and the outer barrel (2) are connected to the negative terminal of the power supply; the inner barrel (3) is connected to the positive terminal of the power supply; the inner barrel (3) can generate ferrous ions.

2. The electrocatalytic treatment device for organic wastewater as described in claim 1, characterized in that: The feeding assembly (7) includes an air supply pipe (71), a waste liquid pipe (72), a dosing pipe (73), and a diffusion pipe (74). The diffusion pipe (74) extends into the inner barrel (3). A plurality of diffusion holes (741) are spaced apart on the diffusion pipe (74) along its extension direction. The output end of the air supply pipe (71) is connected to the input end of the diffusion pipe (74). The output end of the waste liquid pipe (72) is connected to the air supply pipe (71). The output end of the dosing pipe (73) is connected to the waste liquid pipe (72).

3. The electrocatalytic treatment device for organic wastewater as described in claim 2, characterized in that: The diffuser tube (74) is made of metal and is connected to the negative terminal of the power supply.

4. The electrocatalytic treatment device for organic wastewater as described in claim 1, characterized in that: The outer barrel (2) is made of stainless steel, and the inner barrel (3) is made of iron.

5. The electrocatalytic treatment device for organic wastewater as described in claim 1, characterized in that: The connecting hole (31) is located at the lower part of the inner bucket (3), and the overflow hole (21) is located at the upper part of the outer bucket (2).

6. The electrocatalytic treatment device for organic wastewater as described in claim 1, characterized in that: An ultrasonic generator (9) is installed on the outer barrel (2), which is used to increase the interfacial friction between the polytetrafluoroethylene spheres (51) and water.

7. The electrocatalytic treatment device for organic wastewater as described in claim 1, characterized in that: The waste treatment assembly (8) includes an iron packing material (81) and an adsorption packing material (82), which are filled in the third reaction zone (6).

8. The electrocatalytic treatment device for organic wastewater as described in claim 1, characterized in that: The second reaction zone (5) is provided with a sieve (52) for containing polytetrafluoroethylene (PTFE) microspheres (51), which are arranged in the sieve (52).

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