A perfluorooctane sulfonic acid in-situ repair multi-layer porous electrode electrochemical oxidation device

Abstract

The application relates to the technical field of sewage treatment, and discloses a perfluorooctyl sulfonic acid in-situ remediation multi-layer porous electrode electrochemical oxidation device which comprises a protective cover internally provided with a pipeline; an electrode plate which is arranged below the protective cover in parallel with the protective cover and is in communication with an external power supply; and a reaction grid which is arranged in underground water and is fixedly connected between the protective cover and the electrode plate, the top end of the reaction grid is in communication with the water channel in the protective cover, and the bottom end of the reaction grid is electrically connected with the electrode plate, wherein an oxidant is injected into the reaction grid through the pipeline to generate free radicals through electrochemical oxidation, and the free radicals are used for removing perfluorooctyl sulfonic acid pollutants in the underground water. The application can realize efficient underground water remediation, achieves satisfactory pollutant removal effect in a short time, can realize efficient utilization of resources, can be suitable for various underground water environments, and ensures that the remediated underground water meets environmental protection requirements.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a perfluorooctyl sulfonic acid in-situ remediation device for multilayer porous electrode electrochemical oxidation. Background Technology

[0002] As a typical highly stable organic pollutant, PFOS was once widely used in industries such as fire protection, electroplating, and textiles. The unique carbon-fluorine bond structure in its molecules makes it difficult to degrade in the natural environment and it can migrate and spread through groundwater, causing widespread pollution. Investigations of contaminated sites show that PFOS not only exists in topsoil but also easily penetrates into deeper soil layers and groundwater systems, exhibiting significant cross-contamination characteristics. Due to the bioaccumulation and potential toxicity of PFOS, long-term exposure may lead to health risks such as endocrine disruption and immunosuppression, making the remediation of contaminated sites an urgent priority.

[0003] Currently, the remediation of PFOS contamination faces two major technical bottlenecks: First, existing remediation technologies have limited efficiency. Traditional ex-situ remediation methods, such as soil excavation, are not only complex and costly, but may also cause secondary pollution during transportation and disposal. While groundwater extraction can rapidly reduce pollutant concentrations, its removal effect on PFOS is poor, resulting in low long-term economic viability. Second, the ability for synergistic remediation between media is insufficient. Conventional remediation technologies often employ separate treatment models for soil and groundwater, making it difficult to prevent the continuous migration and interaction of pollutants between media. For example, the degradation efficiency of PFOS by chemical oxidation is limited by its chemical inertness, while physical adsorption technology can only achieve phase transfer of pollutants and cannot achieve complete removal.

[0004] To address the aforementioned challenges, electrochemical oxidation technology demonstrates unique application potential. Electrochemical oxidation is an advanced oxidation process based on electrochemical principles. It achieves efficient degradation of pollutants by driving redox reactions at the electrode interface through an applied electric field. Its core mechanism involves two aspects: first, direct oxidation, where pollutants are directly decomposed on the electrode surface through electron transfer; and second, indirect oxidation, utilizing the highly reactive oxidizing species generated by the electrochemical reaction (such as hydroxyl radicals ·OH and sulfate radicals SO4·2). - (etc.) Attacks pollutant molecules. For recalcitrant pollutants like PFOS containing high-energy CF bonds, this technology can gradually break their molecular structure through the directionally generated highly active free radicals, ultimately achieving defluorination and mineralization, and generating harmless products such as carbon dioxide and fluoride ions.

[0005] This technology targets PFOS molecules with active substances generated through electrode interface reactions, effectively breaking their stable CF bond structure. Compared to traditional methods, its advantages are: first, the reaction process does not require the addition of large amounts of chemical reagents, significantly improving environmental compatibility; second, precise degradation of pollutants can be achieved by adjusting electrochemical parameters, avoiding the risk of secondary pollution; and third, it can simultaneously treat dissolved PFOS in soil leachate and groundwater, providing a new approach to solving cross-contamination problems. Currently, research on this technology focuses on electrode material optimization and reaction system design, aiming to improve treatment efficiency and expand its engineering applications, providing a more feasible solution for PFOS pollution control in complex industrial sites.

[0006] Therefore, there is an urgent need for an electrochemical oxidation device for in-situ repair of multilayer porous electrodes using perfluorooctyl sulfonic acid to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes, so as to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides the following solution: The present invention provides an electrochemical oxidation device for in-situ remediation of multilayer porous electrodes using perfluorooctyl sulfonic acid, comprising:

[0009] The protective cover has internal pipes.

[0010] An electrode plate is located below the protective cover and is arranged parallel to the protective cover. The electrode plate is connected to an external power source.

[0011] A reactive grid is located in groundwater and is fixedly connected between the protective cover and the electrode plate. The top of the reactive grid is connected to the water channel inside the protective cover, and the bottom of the reactive grid is electrically connected to the electrode plate. An oxidant is injected into the reactive grid through the pipeline to generate free radicals through electrochemical oxidation. The free radicals are used to remove perfluorooctane sulfonic acid pollutants in the groundwater.

[0012] According to the present invention, a perfluorooctyl sulfonic acid in-situ remediation multilayer porous electrode electrochemical oxidation device is provided, wherein the reaction grid includes a plurality of water purification units, the plurality of water purification units are uniformly distributed in the vertical direction between the protective cover and the electrode plate, and a purification transition cavity is formed between two adjacent water purification units.

[0013] According to the present invention, a perfluorooctyl sulfonic acid in-situ remediation multilayer porous electrode electrochemical oxidation device is provided. The electrode plate includes a first base and a second base. The first base is fixedly connected to the top of the second base. A plurality of electrode slots are provided on the first base, the second base and the protective cover. The electrode slots on the first base and the electrode slots on the second base are coaxially connected. The electrode slots on the first base are connected to the positive terminal of the power supply through a positive electrode line, and the electrode slots on the second base are connected to the negative terminal of the power supply through a negative electrode line.

[0014] According to the present invention, a perfluorooctyl sulfonic acid in-situ remediation multilayer porous electrode electrochemical oxidation device is provided, wherein the water purification unit includes four layers of electrode columns stacked one on top of the other, and the two ends of the electrode columns are respectively connected to the electrode groove on the protective cover and the electrode groove on the electrode plate.

[0015] According to the present invention, a perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes is provided, wherein the electrode column tube has a plurality of small holes.

[0016] According to the present invention, a perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes is provided, wherein the diameters of the four electrode columns from the inside to the outside are 12.5 mm, 25 mm, 37.5 mm and 50 mm, respectively.

[0017] According to the present invention, a perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes is provided, wherein the diameters of the small holes on the four layers of electrode columns are 25 mm, 2.5 mm, 3.75 mm and 5 mm from the inside to the outside, respectively.

[0018] According to the present invention, a perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes is provided, wherein the two ends of the pipeline are respectively connected to the output end of a dosing pump and the input end of a water pump, the input end of the dosing pump is connected to a dosing tank, and the output end of the water pump is connected to a storage tank.

[0019] According to the present invention, a perfluorooctyl sulfonic acid in-situ remediation multilayer porous electrode electrochemical oxidation device is provided, wherein the protective cover is provided with a plurality of through holes, and the pipeline is connected to the water purification unit through the through holes.

[0020] According to the present invention, a perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes is provided, wherein the four layers of electrode columns are arranged from the outside to the inside as positive electrode, negative electrode, positive electrode, negative electrode.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] This invention provides a perfluorooctyl sulfonic acid (PFOS) in-situ remediation multilayer porous electrode electrochemical oxidation device. In use, the device is located in groundwater. The agent is added or sampled through a pipeline into a reaction grid. As water flows into or through the reaction grid, pollutants are electrochemically oxidized or react with free radicals generated by the oxidant, resulting in pollutant removal. This application targets PFOS-contaminated sites, enabling efficient groundwater remediation. The multilayer electrode electrochemical oxidation treatment achieves satisfactory pollutant removal in a short time. The remediation system does not interfere with normal production activities on the surface and achieves efficient resource utilization. It is applicable to various groundwater environments, and its efficient water resource utilization, simplified operation, and convenient management ensure that the remediated groundwater meets environmental protection requirements, demonstrating strong practicality and broad application prospects. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a side view of the overall structure of the present invention;

[0025] Figure 2 This is a perspective view of the overall structure of the present invention;

[0026] Figure 3 This is a schematic diagram of the water purification unit structure of the present invention;

[0027] Figure 4 This is a schematic diagram of the electrode groove distribution of the present invention;

[0028] Figure 5 This is a schematic diagram of the electrode plate structure of the present invention;

[0029] The components include: 1. Dosing tank; 2. Storage tank; 3. Protective cover; 4. Water purification unit; 5. First base; 6. Second base; 7. Dosing pump; 8. Water pump; 9. Purification transition chamber; 10. Through hole; 11. Power supply; 12. Negative electrode line; 13. Positive electrode line; 14. Electrode slot; and 15. Pipeline. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on 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] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1:

[0033] Reference Figures 1-5 This invention provides an electrochemical oxidation device for in-situ remediation of multilayer porous electrodes using perfluorooctyl sulfonic acid, comprising:

[0034] Protective cover 3, with pipe 15 installed inside;

[0035] The electrode plate is located below the protective cover 3 and is arranged parallel to the protective cover 3. The electrode plate is connected to an external power source.

[0036] The reaction grid is located in the groundwater and is fixedly connected between the protective cover 3 and the electrode plate. The top of the reaction grid is connected to the water channel inside the protective cover 3, and the bottom of the reaction grid is electrically connected to the electrode plate. Oxidant is injected into the reaction grid through the pipe 15 to generate free radicals through electrochemical oxidation. The free radicals are used to remove perfluorooctane sulfonic acid pollutants in the groundwater.

[0037] In one embodiment of this application, when in use, the device is located in groundwater, and drugs are added or samples are taken into the reaction grid through the pipe 15. When water flows into the interior of the reaction grid or flows through the reaction grid, pollutants are electrochemically oxidized or react with free radicals generated by the oxidant, and the pollutants are removed by oxidation.

[0038] The scheme is further optimized. The reaction grid includes several water purification units 4. The several water purification units 4 are evenly distributed vertically between the protective cover 3 and the electrode plate. A purification transition cavity 9 is formed between two adjacent water purification units 4.

[0039] In one embodiment of this application, a purification transition cavity 9 is formed between adjacent water purification units 4 and the boundary between water purification unit 4 and water cube.

[0040] The design is further optimized so that the electrode plate includes a first base 5 and a second base 6. The first base 5 is fixedly connected to the top of the second base 6. Several electrode slots 14 are provided on the first base 5, the second base 6 and the protective cover 3. The electrode slots 14 on the first base 5 and the second base 6 are coaxially connected. The electrode slots 14 on the first base 5 are connected to the positive terminal of the power supply 11 through the positive terminal line 13, and the electrode slots 14 on the second base 6 are connected to the negative terminal of the power supply 11 through the negative terminal line 12.

[0041] In one embodiment of this application, a first base 5 containing a positive electrode line and a second base 6 containing a negative electrode line are stacked, and their electrode slots 14 overlap to fix the electrodes. The upper and lower electrode slots 14 are respectively connected to the positive electrode line 13 and the negative electrode line 12, and the positive and negative electrode lines are externally connected to the power supply 11.

[0042] The scheme is further optimized. The water purification unit 4 includes four layers of electrode column tubes that are nested one after another. The two ends of the electrode column tubes are connected to the electrode groove 14 on the protective cover 3 and the electrode groove 14 on the electrode plate, respectively.

[0043] In one embodiment of this application, the electrode groove 14 has a four-ring concentric circle structure, which is adapted to the four-layer electrode column tube.

[0044] To further optimize the design, several small holes were made on the electrode column tube.

[0045] In one embodiment of this application, water can flow through a small hole. When the water flows into or through the water purification unit 4, pollutants are electrochemically oxidized or react with free radicals generated by the oxidant, and the pollutants are removed by oxidation.

[0046] The design was further optimized so that the diameters of the four electrode columns from the inside out are 12.5mm, 25mm, 37.5mm and 50mm respectively.

[0047] The design was further optimized so that the diameters of the small holes on the four-layer electrode column tubes, from the inside out, are 25mm, 2.5mm, 3.75mm and 5mm respectively.

[0048] The scheme is further optimized so that the two ends of the pipeline 15 are respectively connected to the output end of the dosing pump 7 and the input end of the water pump 8. The input end of the dosing pump 7 is connected to the dosing tank 1, and the output end of the water pump 8 is connected to the storage tank 2.

[0049] In one embodiment of this application, the pipeline 15 is a dual-purpose pipeline for both chemical dosing and sampling. The protective cover 3 has an inlet and an outlet at both ends. The pipeline 15 is designed to be sealed. When adding chemicals, the outlet is closed and the oxidant is added through the inlet. When sampling, the inlet is closed and the water sample is extracted through the outlet.

[0050] The design was further optimized by providing several through holes 10 on the protective cover 3, through which the pipe 15 was connected to the water purification unit 4.

[0051] In one embodiment of this application, a pipe 15 is connected to a water purification unit 4 through a through hole 10, which is used to add chemicals to the water purification unit 4 or to take samples.

[0052] The design was further optimized, with the four-layer electrode column arranged from the outside to the inside as positive, negative, positive, negative.

[0053] In one embodiment of this application, there are 14 water purification units 4, each with one sampling hole. During system operation, the water purification units 4 are sampled periodically to evaluate their ability to remove pollutants.

[0054] Example 2:

[0055] Remediation of PFOS-contaminated simulated groundwater was conducted under laboratory conditions. A 1:1 mixture of clay and quartz sand was filled into a 400mm x 300mm x 300mm acrylic container to simulate a subsurface layer of soil and groundwater containing dissolved PFOS contaminants. A sampling port for simulated groundwater was provided on the side of the experimental container. The specific remediation steps are as follows:

[0056] Turn off the dosing pump 7 and turn on the water pump 8 to pump the groundwater containing PFOS into the storage tank 2 at a flow rate of 10 mL / min. After the groundwater in the storage tank 2 exceeds 50 mL, turn off the water pump 8 and measure the PFOS concentration in the storage tank 2, which is 12.6 mg / L.

[0057] Turn on power supply 11 and adjust the current to 1A to perform pre-oxidation;

[0058] After 30 minutes of pre-oxidation, turn on the dosing pump 7 at a flow rate of 10 mL / min to inject 200 mM potassium persulfate from the dosing tank 1 into the groundwater. At the same time, adjust the current of the power supply 11 to 2 A to carry out the oxidation reaction.

[0059] Every 10 minutes, pump 8 is turned on to pump groundwater containing PFOS into storage tank 2 at a flow rate of 10 mL / min. Once the groundwater in storage tank 2 exceeds 50 mL, pump 8 is turned off, and the PFOS concentration in storage tank 2 is measured. Subsequently, dosing pump 7 is turned on at a flow rate of 10 mL / min to inject 200 mM potassium persulfate from dosing tank 1 into the groundwater. This operation is repeated sequentially.

[0060] Experiments showed that after 6 hours, the residual concentration of pollutants in the soil of storage tank 2 and the simulated groundwater flowing through the seepage channel was significantly reduced, with the removal rate of PFOS in the soil reaching 81.4%. After 24 hours, PFOS in the soil was completely removed. This indicates that the reactor of this invention is effective in removing PFOS pollutants from groundwater, and the remediation technology of this invention is simple and easy to operate.

[0061] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0062] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes, characterized in that, include: The protective cover (3) has a pipe (15) inside; The electrode plate is located below the protective cover (3) and is arranged parallel to the protective cover (3). The electrode plate is connected to an external power source. A reaction grid is located in groundwater and is fixedly connected between the protective cover (3) and the electrode plate. The top of the reaction grid is connected to the water channel inside the protective cover (3), and the bottom of the reaction grid is electrically connected to the electrode plate. Oxidant is injected into the reaction grid through the pipe (15) to generate free radicals through electrochemical oxidation. The free radicals are used to remove perfluorooctane sulfonic acid pollutants in the groundwater. The reaction grid includes several water purification units (4), which are evenly distributed vertically between the protective cover (3) and the electrode plate. A purification transition cavity (9) is formed between two adjacent water purification units (4). The electrode plate includes a first base (5) and a second base (6). The first base (5) is fixedly connected to the top of the second base (6). Several electrode grooves (14) are provided on the first base (5), the second base (6), and the protective cover (3). The electrode grooves (14) on the first base (5) and the electrode grooves (14) on the second base (6) are provided with a number of electrode slots (14). The electrode slots (14) are coaxially connected. The electrode slots (14) on the first base (5) are connected to the positive terminal of the power supply (11) through the positive terminal line (13), and the electrode slots (14) on the second base (6) are connected to the negative terminal of the power supply (11) through the negative terminal line (12). The water purification unit (4) includes four layers of electrode column tubes stacked one on top of the other. The two ends of the electrode column tubes are connected to the electrode slots (14) on the protective cover (3) and the electrode slots (14) on the electrode plate, respectively. Several small holes are opened on the electrode column tubes. The four layers of electrode column tubes are arranged from the outside to the inside in the order of positive, negative, positive, negative.

2. The perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes according to claim 1, characterized in that: The diameters of the four electrode columns, from the inside out, are 12.5 mm, 25 mm, 37.5 mm, and 50 mm, respectively.

3. The perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes according to claim 2, characterized in that: The diameters of the small holes on the four electrode columns, from the inside out, are 1.25 mm, 2.5 mm, 3.75 mm, and 5 mm, respectively.

4. The perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes according to claim 1, characterized in that: The two ends of the pipeline (15) are respectively connected to the output end of the dosing pump (7) and the input end of the water pump (8). The input end of the dosing pump (7) is connected to the dosing tank (1), and the output end of the water pump (8) is connected to the storage tank (2).

5. The perfluorooctyl sulfonic acid in-situ repair electrochemical oxidation device for multilayer porous electrodes according to claim 1, characterized in that: The protective cover (3) has several through holes (10), and the pipe (15) is connected to the water purification unit (4) through the through holes (10).

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