Groundwater circulation well primary cell remediation device and method based on a biochar electrode

Abstract

This invention relates to the field of in-situ groundwater remediation, and discloses a groundwater circulating well galvanic cell remediation device and method based on biochar electrodes. The device includes: a circulating well body comprising a first screen section and a second screen section; an injection unit for pumping contaminated groundwater from the first screen section into the second screen section, treating it, and then reinjecting it into the aquifer from the second screen section, forming a groundwater circulating flow field; and a galvanic cell assembly comprising a storage unit, a cathode assembly, an anode assembly, and a proton exchange membrane, disposed in the second screen section, for degrading pollutants in the groundwater. This invention achieves pollutant degradation and removal by injecting an oxidant into the storage unit to react with groundwater pollutants collected in the second screen section, utilizing the cathode and anode assemblies to transfer electrons, thus avoiding direct contact between the oxidant and pollutants. The entire process reduces the generation of highly toxic intermediate products and the toxic effects on native microorganisms, thereby reducing the risk of secondary pollution of the groundwater environment and achieving the goal of green and low-carbon remediation.

Description

Technical Field

[0001] This invention relates to the field of in-situ groundwater remediation technology, specifically to a device and method for remediating galvanic cells in groundwater circulating wells based on biochar electrodes. Background Technology

[0002] With the acceleration of industrialization and urbanization and the expansion of agricultural activities, groundwater pollution has become increasingly serious, posing a severe threat to ecosystems and human health. Among in-situ groundwater remediation technologies, circulating well technology, which minimizes aquifer disturbance, requires less land, and consumes less energy, has been widely adopted.

[0003] Circulating well technology uses vacuum pumps to inject water into the well, using hydraulic power to drive the surrounding contaminated groundwater to flow into the well. In recent years, various oxidation technologies coupled with circulating wells have been able to effectively remove volatile / semi-volatile organic compounds from groundwater. However, directly injecting oxidants and catalysts into the formation poses problems such as high risk of secondary pollution, aquifer blockage, and high remediation costs.

[0004] The prior art discloses a circulating well system for in-situ remediation of organically contaminated groundwater, such as... Figure 1 As shown, the well pipe unit includes a circulating inlet screen pipe 01 and a circulating outlet screen pipe. The circulating treatment chamber 02 is installed inside the circulating outlet screen pipe. A circulating water pump 03 is installed between the circulating inlet screen pipe 01 and the circulating treatment chamber 02. The circulating water pump 03 injects groundwater from the contaminated area into the circulating treatment chamber 02 through the circulating inlet screen pipe 01. The chemical unit 04 injects oxidizing agent into the circulating treatment chamber 02 to treat the contaminated groundwater. After treatment, the water enters the circulating outlet screen pipe, is filtered, and then flows out of the well pipe unit.

[0005] However, in this technology, the oxidant comes into direct contact with polluted groundwater, which can alter the underground reducing environment and produce toxic and harmful byproducts, posing a risk of secondary pollution. Summary of the Invention

[0006] In view of this, the present invention designs a biochar electrode galvanic cell oxidation device coupled with a circulating well remediation technology, which can achieve pollutant degradation and removal under the condition of avoiding direct contact between oxidant and pollutants. The whole process can reduce the generation of highly toxic intermediate products and the toxic effects on native microorganisms, thereby reducing the risk of secondary pollution of groundwater environment and achieving the purpose of green and low-carbon remediation.

[0007] In a first aspect, the present invention provides a groundwater circulating well galvanic cell repair device based on a biochar electrode, comprising:

[0008] A circulation well body is located below the surface. The circulation well body includes a first screen section and a second screen section. The first screen section is located on one side of the second screen section. The first screen section has an inlet that connects to the aquifer, and the second screen section has an outlet that connects to the underground.

[0009] A water pumping device is disposed between the first screen section and the second screen section, and is used to pump the groundwater from the first screen section into the second screen section to realize the circulation of groundwater in the aquifer.

[0010] A primary battery assembly is located on the side of the second sieve segment away from the first sieve segment, and is used to degrade pollutants in the groundwater;

[0011] The primary battery assembly includes:

[0012] A liquid storage device is disposed on the side of the second sieve segment away from the first sieve segment. The liquid storage device includes a first cavity for storing a solution containing an oxidant. The liquid storage device is provided with a first through hole and a second through hole connecting the first cavity and the second sieve segment.

[0013] A cathode assembly, disposed within the first cavity, is used to contact the oxidant;

[0014] An anode assembly, disposed within the second sieve section, passes through the first through-hole and is connected to the cathode assembly, for contacting pollutants in the groundwater;

[0015] A proton exchange membrane is fixed at the second through-hole and is used to transfer protons from the first cavity to the second sieve section without other solute exchange.

[0016] Beneficial Effects: By storing the oxidant in the first chamber and the pollutants in the groundwater in the second sieve section, and connecting the cathode assembly to the oxidant solution to form a cathode electrode and the anode assembly to the polluted groundwater to form a positron electrode, a potential difference can be created between the cathode and anode assemblies. When the potential of the cathode assembly rises above the potential required for the oxidation of the pollutants, the pollutants lose electrons and are oxidized and degraded. The oxidant is then transferred through the anode assembly to the cathode assembly, where it gains electrons and is reduced and decomposed. Protons are transferred through the proton exchange membrane, forming a current loop with the electron transfer, thus completing the continuous degradation of the pollutants. The entire process avoids direct contact between the oxidant and the pollutants, preventing the oxidant from directly contacting the pollutants. Excessive disturbance to the groundwater reduction environment reduces the generation of highly toxic intermediate products and their toxic effects on native microorganisms, thereby reducing the risk of secondary pollution of the groundwater environment and achieving the goal of green and low-carbon remediation. It can also improve the utilization rate of oxidants and the degradation capacity of pollutants. By using a pumping unit to pump groundwater from the first screen section to the second screen section, a pressure difference is created between the first and second screen sections, which can drive groundwater from the surrounding circulation well to continuously enter the first screen section, thereby improving the treatment efficiency of pollutants. At the same time, it can regulate the movement direction of the pollution range and prevent pollution diffusion. The proton exchange membrane only allows positively charged hydrogen ions to pass through, which can maintain the charge balance of the system and ensure the continuous flow of current.

[0017] In one alternative embodiment, the cathode assembly includes:

[0018] Cathode components are used to transmit electrons;

[0019] A first catalyst is mounted on the surface of the cathode and is used to connect with a solution containing the oxidant.

[0020] And / or, the anode assembly includes:

[0021] Anode components are used to transmit electrons;

[0022] A second catalyst element, mounted on the surface of the anode element, is used to connect with groundwater containing the pollutants.

[0023] Beneficial effects: By setting the first catalyst and the second catalyst, a potential difference can be formed on the cathode and the anode, thereby realizing electron transfer; fixing the first catalyst on the cathode and the second catalyst on the anode can improve the electron transfer efficiency and also prevent the second catalyst from entering the aquifer with the degraded groundwater and clogging the aquifer.

[0024] In one optional embodiment, the cathode and / or the anode are columnar and sheet-like structures;

[0025] And / or, the cathode and / or the anode are made of graphite material;

[0026] And / or, the first catalyst and / or the second catalyst are made of biochar material.

[0027] Beneficial effects: By setting up a large number of first and second catalysts, the contact area of ​​the oxidant can be increased, thereby increasing the potential difference between the cathode and anode to improve the electron transfer rate and thus improve the pollutant degradation efficiency; by using biochar fixed on graphite for conductivity, it is not easily corroded, will not cause secondary pollution to groundwater, and has low production cost.

[0028] In one optional embodiment, the biochar electrode-based groundwater circulating well galvanic cell remediation device includes:

[0029] A detection component is disposed in the first cavity and / or the second sieve section. The detection component is electrically connected to the water injection component and is used to adjust the output power of the water injection component according to the detection value.

[0030] Beneficial effects: By setting up a detection component, it is possible to analyze the oxidation-reduction status of the liquid in the first chamber and the second sieve section, thereby adjusting the rate of groundwater flow into the second sieve section and the amount of oxidant flowed into the first chamber, and determining whether the cathode and anode components should be replaced.

[0031] In one optional implementation, the detection component includes:

[0032] The first detection element is disposed in the first cavity and is used to detect the liquid concentration in the first cavity;

[0033] And / or, a second detection element, disposed within the second sieve section, for detecting the liquid concentration within the second sieve section.

[0034] In one optional embodiment, the biochar electrode-based groundwater circulating well galvanic cell remediation device includes:

[0035] A first storage container holds the oxidant and / or electrolyte, and the first storage container is in communication with the first cavity for supplying the oxidant and / or electrolyte into the first cavity;

[0036] And / or, a second storage device, in communication with the first cavity, for recovering the electrolyte within the first cavity;

[0037] And / or, a packer, fixed within the circulation well body, for separating the first screen section and the second screen section.

[0038] Beneficial effects: By recycling the electrolyte, the concentration of anions in the first chamber can be reduced, and the amount of waste liquid discharged can be reduced.

[0039] In one optional embodiment, the first cavity is provided with a stirring element to accelerate the dissolution of the oxidant and / or the electrolyte;

[0040] And / or, the surface of the proton exchange membrane near the second sieve segment is provided with an anti-deposition layer.

[0041] Beneficial effects: By incorporating a stirring element, the oxidant and electrolyte can be rapidly dissolved and diffused, ensuring sufficient contact between the oxidant and the surface of the first catalyst; by incorporating an anti-deposition layer, Ca2+ can be inhibited. 2+ or Mg 2+ Scaling allows proton exchange membranes to operate for extended periods in groundwater with a hardness greater than 500 mg / L without the need for cleaning.

[0042] In one alternative embodiment, the first storage component is connected to the first cavity via a pipe, and the stirring component is located at the end of the pipe away from the first storage component.

[0043] Beneficial effect: By placing the agitator at the end of the pipe, the structure can be simplified.

[0044] In one alternative embodiment, the size of the liquid storage element is smaller than the size of the second screen section along the length extension direction of the circulation well body;

[0045] And / or, the liquid storage component is detachably fixed to the circulation well body;

[0046] And / or, a loading and unloading guide structure is provided above the liquid storage device.

[0047] Beneficial effects: By detachably connecting the reservoir to the circulation well body, it is easy to replace the cathode assembly, anode assembly, and proton exchange membrane; by setting a loading and unloading guide structure, it is easy to replace the reservoir.

[0048] Secondly, the present invention also provides a method for repairing galvanic cells in groundwater circulation wells based on biochar electrodes, applied to the aforementioned biochar electrode-based groundwater circulation well galvanic cell repair device, comprising:

[0049] The groundwater enters the first screen section through the inlet;

[0050] The groundwater is pumped into the second screen section through the pumping and injection device;

[0051] The cathode assembly is connected to a solution containing the oxidant, and the anode assembly is connected to groundwater containing the pollutant;

[0052] Electrons in the pollutant are transferred to the oxidant, and protons in the first cavity are transported to the second sieve section through the proton exchange membrane, forming a current loop with the electron transfer to achieve the degradation of the pollutant;

[0053] The degraded groundwater is discharged from the outlet.

[0054] Beneficial effects: Since the biochar electrode-based groundwater circulation well galvanic cell repair method is applied to the biochar electrode-based groundwater circulation well galvanic cell repair device, it has the same effect as the biochar electrode-based groundwater circulation well galvanic cell repair device, and will not be elaborated here. Attached Figure Description

[0055] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0056] Figure 1 This is a schematic diagram of a circulating well system for in-situ remediation of organically contaminated groundwater, based on existing technology.

[0057] Figure 2 This is a schematic diagram of a groundwater circulating well galvanic cell repair device based on a biochar electrode, according to an embodiment of the present invention.

[0058] Figure 3 This is an experimental schematic diagram of a groundwater circulating well galvanic cell repair device based on a biochar electrode, according to an embodiment of the present invention.

[0059] Figure 4 for Figure 3 The experimental results are shown in the figure.

[0060] Explanation of reference numerals in the attached figures:

[0061] 01. Circulating water inlet screen; 02. Circulating treatment chamber; 03. Circulating water pump; 04. Chemical unit;

[0062] 1. Circulation well body; 101. First screen section; 1011. Inlet; 102. Second screen section; 1021. Outlet; 2. Pumping / injection components; 3. Storage components; 301. Loading / unloading guide structure; 4. Cathode assembly; 401. Cathode component; 402. First catalyst component; 5. Anode assembly; 501. Anode component; 502. Second catalyst component; 6. Proton exchange membrane; 7. Detection components; 701. Sulfate ion concentration monitor; 702. Oxygen concentration monitor; 703. pH value monitor; 704. Total organic carbon concentration monitor; 8. First storage component; 9. Second storage component; 10. Seal; 11. Stirring component; 12. Pipeline; 13. Controller; 14. Gas collection component; 15. Sodium persulfate; 16. 2,4,6-Trichlorophenol. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0064] The following is combined Figures 2 to 4 The following describes embodiments of the present invention.

[0065] According to an embodiment of the present invention, in one aspect, a groundwater circulation well galvanic cell remediation device based on biochar electrodes is provided, comprising: a circulation well body 1, disposed below the ground surface, the circulation well body 1 including a first screen section 101 and a second screen section 102, the first screen section 101 being disposed on one side of the second screen section 102, the first screen section 101 having an inlet 1011 communicating with the aquifer, and the second screen section 102 having an outlet 1021 communicating with the ground; a water injection / extraction component 2, disposed between the first screen section 101 and the second screen section 102, for pumping groundwater from the first screen section 101 into the second screen section 102 to achieve groundwater circulation in the aquifer; and a galvanic cell assembly, disposed in the second screen section 102 away from the first screen section 101. On one side of 1, it is used to degrade pollutants in groundwater; wherein, the galvanic cell assembly includes: a liquid storage component 3, disposed on the side of the second sieve section 102 away from the first sieve section 101, the liquid storage component 3 includes a first cavity, the first cavity is used to store a solution containing an oxidant, the liquid storage component 3 is provided with a first through hole and a second through hole connecting the first cavity and the second sieve section 102; a cathode assembly 4, disposed in the first cavity, used to contact the oxidant; an anode assembly 5, disposed in the second sieve section 102, passing through the first through hole and connected to the cathode assembly 4, used to contact pollutants in groundwater; a proton exchange membrane 6, fixed at the second through hole, used to transfer protons in the first cavity to the second sieve section 102 without other solute exchange.

[0066] By storing the oxidant in the first chamber and the pollutants in the groundwater in the second sieve section 102, and connecting the cathode assembly 4 to the oxidant solution to form a cathode electrode and the anode assembly 5 to the polluted groundwater to form a cathode electrode, a potential difference can be created between the cathode assembly 4 and the anode assembly 5. When the potential of the cathode assembly 4 rises above the potential required for the oxidation of the pollutants, the pollutants lose electrons and are oxidized and degraded. The oxidant is then transferred to the cathode assembly 4 through the anode assembly 5, where it gains electrons and is reduced and decomposed. Protons are transferred through the proton exchange membrane 6, forming a current loop with the electron transfer, thereby completing the continuous degradation of the pollutants. The entire process avoids direct contact between the oxidant and the pollutants, preventing the oxidant from affecting the reduction of the groundwater. Excessive environmental disturbance reduces the generation of highly toxic intermediate products and the toxic effects on native microorganisms, thereby reducing the risk of secondary pollution of groundwater environment and achieving the goal of green and low-carbon remediation. It can also improve the utilization rate of oxidant and the degradation capacity of pollutants. The groundwater in the first screen section 101 is pumped to the second screen section 102 by the pumping water injection device 2, so that a pressure difference is formed between the first screen section 101 and the second screen section 102. This can drive the groundwater around the circulation well body 1 to continuously enter the first screen section 101, thereby improving the treatment efficiency of pollutants. At the same time, it can regulate the movement direction of the pollution range and prevent the spread of pollution. The proton exchange membrane 6 only allows positively charged hydrogen ions to pass through, which can maintain the charge balance of the system and ensure the continuous flow of current.

[0067] like Figure 2 As shown, in one embodiment, the circulation well body 1 is vertically positioned below the ground surface, and the second screen section 102 is positioned above and adjacent to the first screen section 101. As an alternative implementation, the second screen section 102 may also be positioned obliquely to the first screen section 101, or the second screen section 102 may be positioned on one side of the first screen section 101 along the horizontal direction. As an alternative implementation, the second screen section 102 may also be spaced apart from the first screen section 101.

[0068] like Figure 2 As shown, in one embodiment, the water injection component 2 includes a water pump and a water pipe connected to the water pump. The inlet end of the water pipe is located within the first screen section 101, and the outlet end is located within the second screen section 102. The water pump pumps groundwater from the first screen section 101 into the second screen section 102 through the water pipe. The portion of the water pipe located within the second screen section 102 has multiple openings to form the outlet end. As an alternative implementation, other pumping structures such as air pumps can also be used, and no further restrictions are imposed here.

[0069] like Figure 2As shown, in one embodiment, the size of the liquid storage element 3 is smaller than the size of the second screen section 102 along the length extension direction of the circulation well body 1. Specifically, the size of the liquid storage element 3 is half the size of the second screen section 102 along the length extension direction of the circulation well body 1. As a possible implementation, the size of the liquid storage element 3 is determined according to the shape and size of the second screen section 102, and no further restrictions are imposed here.

[0070] In one embodiment, the liquid storage component 3 is detachably fixed to the circulation well body 1. Specifically, the inner wall of the circulation well body 1 is provided with multiple grooves at intervals, and the outer wall of the liquid storage component 3 is provided with multiple retractable protrusions, which are engaged in the grooves for fixation. By detachably connecting the liquid storage component 3 to the circulation well body 1, it is convenient to replace the cathode assembly 4, the anode assembly 5, and the proton exchange membrane 6. As an alternative implementation, the liquid storage component 3 can also be detachably connected to the circulation well body 1 in other ways, without further limitations.

[0071] like Figure 2 As shown, in one embodiment, the first through hole and the second through hole are provided on the side of the liquid storage member 3 near the first sieve section 101, and the first through hole and the second through hole are spaced apart.

[0072] like Figure 2 As shown, in one embodiment, a loading / unloading guide structure 301 is provided above the liquid storage component 3. The loading / unloading guide structure 301 facilitates the replacement of the liquid storage component 3. Alternatively, the liquid storage component 3 may partially extend out of the circulation well body 1, with an opening in the extended portion for the loading / unloading guide structure.

[0073] In one embodiment, sodium persulfate is used as the oxidant. Sodium persulfate can improve electron transfer efficiency and can efficiently activate the biochar electrode surface. As an alternative implementation, the oxidant may also be one or more combinations of other oxidants such as sodium persulfate, potassium persulfate, and potassium persulfate.

[0074] like Figure 2 As shown, in one embodiment, the cathode assembly 4 includes: a cathode element 401 for electron transfer; and a first catalyst element 402, loaded on the surface of the cathode element 401, for connection with a solution containing an oxidant. The anode assembly 5 includes: an anode element 501 for electron transfer; and a second catalyst element 502, loaded on the surface of the anode element 501, for connection with groundwater containing pollutants. The cathode element 401 and the anode element 501 are columnar and sheet-like structures, respectively, with sheet-like structures connected to both sides of the columnar structure; multiple sheet-like structures are provided, with multiple sheet-like structures spaced apart on each side of the columnar structure. Further, the loading amount of the first catalyst element 402 on the cathode element 401 and the loading amount of the second catalyst element 502 on the anode element 501 are both 0 g / m³. 2 -10g / m2 By setting the first catalyst 402 and the second catalyst 502, a potential difference can be formed on the cathode 401 and the anode 501, thereby realizing electron transfer. Fixing the first catalyst 402 to the cathode 401 and the second catalyst 502 to the anode 501 can improve the electron transfer efficiency and prevent the second catalyst 502 from entering the aquifer with the degraded groundwater and clogging the aquifer. By setting a large number of first catalysts 402 and second catalysts 502, the contact area of ​​the oxidant can be increased, thereby increasing the potential difference between the cathode 401 and the anode 501, improving the electron transfer rate, and thus improving the pollutant degradation efficiency. As an alternative implementation, the cathode 401 and the anode 501 can also be other irregular structures such as cross-shaped structures, without much limitation. As an alternative implementation, the first catalyst 402 and the second catalyst 502 can also be spherical or polygonal structures, without much limitation. As an alternative implementation, the number of first catalyst 402 and second catalyst 502 can be determined according to actual conditions, and no restrictions are imposed here. As an alternative implementation, the loading of the first catalyst 402 on the cathode 401 and the loading of the second catalyst 502 on the anode 501 can also be greater than 10 g / m³. 2 such as 11g / m 2 The specific details can be adjusted according to actual needs.

[0075] In one embodiment, the cathode 401 and anode 501 are made of graphite, while the first catalyst 402 and the second catalyst 502 are made of biochar. Conducting electricity by fixing biochar onto graphite is less prone to corrosion, avoids secondary pollution of groundwater, and has low production costs. As an alternative embodiment, the cathode 401 and anode 501 can also be made of insulating materials such as mica. As an alternative embodiment, the first catalyst 402 and the second catalyst 502 can also be made of glassy carbon or other non-metallic materials.

[0076] In one embodiment, the cathode assembly 4 and the anode assembly 5 are prepared as follows:

[0077] Step 1: Wash the shrimp shells with tap water, dry them, and crush them into particles smaller than 2mm.

[0078] Step 2: Weigh 10g of shrimp shells and 40g of melamine and mix them in a crucible. Then transfer the mixture to a muffle furnace, evacuate the furnace, introduce nitrogen gas, and heat the mixture at a rate of 5°C / min. -1 After heating to 900℃ and holding for 2 hours, the crucible is removed and allowed to cool naturally to room temperature. The black substance inside the crucible is biochar.

[0079] Step 3: Take out the biochar and grind it with an agate mortar ball for 30 minutes. Wash each 25g of biochar with 1L of 1mol / L hydrochloric acid solution for 4 hours. Then, after centrifugation at 2900g for 20 minutes, wash it again with hydrochloric acid solution. Repeat the washing process three times and then wash it with deionized water until neutral.

[0080] Step 4: After drying the treated biochar in a vacuum drying oven at 60°C, grind it again to a particle size of 50-200nm, filter it through a 100-mesh sieve, and store it in a desiccator for later use.

[0081] Step 5: Mix the biochar in the desiccator with Nafion solution, isopropanol and ultrapure water, sonicate to mix well, then drop it onto the surface of the graphite rod and let it air dry.

[0082] The porous structure, surface functional groups, and highly aromatic structure of the aforementioned biochar can improve electron transfer efficiency. By using melamine as an external nitrogen source for biochar and doping it with nitrogen, the π-π conjugated system can be broadened, forming an electron-rich structure with CN bonds on the surface, enhancing the conductivity of the biochar, thereby enhancing catalytic activity and increasing the electron transfer rate to 2-3 times that of traditional biochar. High-temperature calcination of biochar (≥900℃) can further improve electron transfer capacity. Vacuum extraction and high-temperature calcination can regulate the degree of order, surface functional groups, and specific surface area of ​​the carbon structure in biochar, giving it conductivity, redox activity, and adsorption capacity. As an alternative implementation method, other animal and plant wastes such as fish bones and corn stalks can also be used as raw materials for biochar preparation. As an alternative implementation method, urea can be used for nitrogen doping, or biomass with high nitrogen content can be used directly as raw materials for biochar preparation.

[0083] like Figure 3 As shown, cathode assembly 4 and anode assembly 5 were immersed in a cathode chamber and an anode chamber respectively containing 100 mL of 0.05 mmol / L sodium sulfate solution. The cathode and anode chambers were connected by a proton exchange membrane 6. 1 mmol / L sodium persulfate 15 was added to the cathode chamber, and 20 mg / L 2,4,6-trichlorophenol 16 was added to the anode chamber. Magnetic stirring structures were installed in both the cathode and anode chambers for stirring. Samples were taken from the anode chamber every 1 hour, for a total of four times. The concentration of 2,4,6-trichlorophenol 16 was determined and detected using high-performance liquid chromatography (HPLC). The concentration of residual 2,4,6-trichlorophenol 16 in the anode chamber was calculated. Figure 4 As shown, the concentration of 2,4,6-trichlorophenol 16 remaining in the anode chamber after 4 hours was 0.33 mg / L, which means that the removal rate of 2,4,6-trichlorophenol 16 in the anode chamber was 98.35%.

[0084] In one embodiment, the proton exchange membrane 6 has an anti-deposition layer on its surface near the second sieve section 102. Specifically, the anti-deposition layer is a mixture of polyacrylate, organophosphonate, and acrylamide copolymer; the thickness of the anti-deposition layer is 50 nm-100 nm. By providing the anti-deposition layer, Ca2+ can be suppressed. 2+ or Mg 2+ Scaling allows the proton exchange membrane 6 to operate for extended periods in groundwater with a hardness greater than 500 mg / L without the need for cleaning. As an alternative implementation, the anti-deposition layer can also be other zwitterionic polymers such as sulfonate betaine, or a 20 kHz-40 kHz ultrasonic transducer can be fixed near the proton exchange membrane 6 to inhibit the deposition of organic matter, inorganic ions, and solid particles on the surface of the proton exchange membrane 6 through ultrasonic action. As an alternative implementation, the thickness of the anti-deposition layer can also be 40 nm or 110 nm; no further limitations are imposed here.

[0085] In one embodiment, the groundwater circulating well galvanic cell repair device based on biochar electrode includes: a detection component 7, disposed within a first cavity and a second sieve section 102, electrically connected to a water pumping unit 2, used to adjust the output power of the water pumping unit 2 according to the detected value. Further, the detection component 7 includes: a first detection element, disposed within the first cavity, used to detect the liquid concentration within the first cavity; and a second detection element, disposed within the second sieve section 102, used to detect the liquid concentration within the second sieve section 102. By setting the detection component 7, the redox state of the liquid within the first cavity and the second sieve section 102 can be analyzed, thereby adjusting the rate of groundwater flow into the second sieve section 102 and the amount of oxidant introduced into the first cavity, and determining whether the cathode assembly 4 and the anode assembly 5 should be replaced. Alternatively, the detection component 7 can be omitted, and instead, oxidant can be periodically added to the first cavity, with the water pump output power adjusted to a lower level.

[0086] In one embodiment, the groundwater circulating well galvanic cell remediation device based on a biochar electrode includes: a gas tank, connected to a first chamber, for aerating the first chamber to increase the oxygen concentration within it. By aerating the first chamber, oxygen can be adsorbed onto the surface of the first catalyst 402 to rapidly increase the potential of the cathode 401, thereby enhancing the degradation capacity of pollutants. Alternatively, the gas tank may not be included in the embodiment.

[0087] like Figure 2As shown, in one embodiment, the first detection element includes a sulfate ion concentration monitor 701 and an oxygen concentration monitor 702, used to acquire information on persulfate ion reduction and changes in oxygen concentration. The second detection element includes a pH monitor 703 and a total organic carbon concentration monitor 704, used to acquire information on the pH and pollutant degradation in the groundwater. Specifically, when the total organic carbon concentration is >200 mg / L, the water pump flow rate is adjusted to ≤0.8 m³ / L. 3 / h; When the total organic carbon concentration is <50mg / L, adjust the water pump flow rate to ≥2m 3 / h.

[0088] like Figure 2 As shown, in one embodiment, both the detection component 7 and the water pump are electrically connected to the controller 13. The detection component 7 transmits the detection data to the controller 13, which then processes the data and controls the output power of the water pump.

[0089] like Figure 2 As shown, in one embodiment, the groundwater circulating well galvanic cell repair device based on a biochar electrode includes: a first storage unit 8 storing an oxidant and an electrolyte, the first storage unit 8 being connected to a first cavity for supplying the oxidant and electrolyte to the first cavity. Both the oxidant and electrolyte are in powder form. The first storage unit 8 has two chambers, one for storing the oxidant powder and the other for storing the electrolyte powder, both of which are connected to the first cavity. Alternatively, an opening may be provided in the liquid storage unit 3 for adding the oxidant to the first cavity. Alternatively, two storage units may be provided, one for storing the oxidant powder and the other for storing the electrolyte powder.

[0090] like Figure 2 As shown, in one embodiment, the groundwater circulating well galvanic cell repair device based on a biochar electrode includes: a second storage unit 9, connected to a first cavity, for recovering the electrolyte in the first cavity. The electrolyte is a sodium sulfate solution, and the water level line covers the end of the cathode 401. By recovering the electrolyte, the anion concentration in the first cavity can be reduced, and the amount of waste liquid discharged can be reduced. As an alternative implementation, a separate connecting pipe can also be provided for discharging waste liquid.

[0091] In one embodiment, a sedimentation tank with a slope >5° is provided at the bottom of the second storage unit 9. Waste liquid in the first chamber is periodically discharged into the sedimentation tank, and a CaCl2 solution with a concentration of 0.5mol / L-1.0mol / L is added to the waste liquid. 2+ Able to react with SO4 in waste liquid 2- CaSO4 precipitate is generated, and the precipitate is gypsum, which is then recovered; the remaining clear liquid is reinjected into the first chamber.

[0092] like Figure 2As shown, in one embodiment, the groundwater circulating well galvanic cell repair device based on biochar electrode includes: a packer 10, fixed inside the circulating well body 1, used to separate a first sieve segment 101 and a second sieve segment 102. The packer 10 is a packer with a cross-sectional shape identical to that of the circulating well body 1. Alternatively, in a different implementation, the first sieve segment 101 and the second sieve segment 102 can be two separate housings, in which case the packer 10 is not required.

[0093] In one embodiment, a stirring element 11 is provided in the first cavity to accelerate the dissolution of the oxidant and electrolyte. The stirring element 11 is a rotating blade with thin, right-angled blades. By providing the stirring element 11, the oxidant and electrolyte can be rapidly dissolved and diffused, ensuring sufficient contact between the oxidant and the surface of the first catalyst 402. As an alternative embodiment, the stirring element 11 can also be a magnetic stirring structure. As an alternative embodiment, the blades can also be thick-angled, thin-angled, or other irregular shapes; no further limitations are imposed here.

[0094] In one embodiment, the first storage container 8 is connected to the first cavity via a pipe 12, and the stirring element 11 is located at the end of the pipe 12 away from the first storage container 8. By placing the stirring element 11 at the end of the pipe 12, the structure can be simplified. As an alternative implementation, a separate support platform can also be provided above the liquid storage container 3 to fix the stirring element 11.

[0095] like Figure 2 As shown, in one embodiment, the groundwater circulating well galvanic cell remediation device based on biochar electrode includes: a gas collection element 14, disposed above the circulating well body 1, for collecting volatile gases in the groundwater. After collecting the volatile gases, the gas collection element 14 conveys them to a gas treatment element, which contains an activated carbon filter plate for adsorbing and treating the volatile gases before releasing them into the air.

[0096] According to an embodiment of the present invention, another aspect provides a method for remediating a galvanic cell in a groundwater circulating well based on a biochar electrode, applied to the aforementioned remediation device for a groundwater circulating well based on a biochar electrode, comprising: groundwater entering a first screen section 101 through an inlet 1011; pumping the groundwater into a second screen section 102 through an injection pump 2; connecting a cathode assembly 4 to a solution containing an oxidant, and connecting an anode assembly 5 to groundwater containing pollutants; transferring electrons from the pollutants to the oxidant, and transferring protons in the first chamber to the second screen section 102 through a proton exchange membrane 6, forming a current loop with the electron transfer to achieve pollutant degradation; and discharging the degraded groundwater from an outlet 1021.

[0097] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A device for repairing galvanic cells in groundwater circulating wells based on biochar electrodes, characterized in that, include: The circulating well body (1) is located below the ground surface. The circulating well body (1) includes a first screen section (101) and a second screen section (102). The first screen section (101) is located on one side of the second screen section (102). The first screen section (101) is provided with an inlet (1011) that connects to the aquifer. The second screen section (102) is provided with an outlet (1021) that connects to the underground. The water injection device (2) is located between the first screen section (101) and the second screen section (102) to pump the groundwater from the first screen section (101) into the second screen section (102) so as to realize the circulation of groundwater in the aquifer. A primary battery assembly is disposed on the side of the second sieve section (102) away from the first sieve section (101) for degrading pollutants in the groundwater; The primary battery assembly includes: The liquid storage device (3) is located on the side of the second sieve section (102) away from the first sieve section (101). The liquid storage device (3) includes a first cavity for storing a solution containing an oxidant. The liquid storage device (3) is provided with a first through hole and a second through hole connecting the first cavity and the second sieve section (102). A cathode assembly (4) is disposed in the first cavity for contacting the oxidant. The cathode assembly (4) includes: a cathode element (401) for transferring electrons; and a first catalyst element (402) loaded on the surface of the cathode element (401) for connecting with a solution containing the oxidant. An anode assembly (5) is disposed within the second sieve section (102), passes through the first through hole and is connected to the cathode assembly (4) for contacting pollutants in the groundwater. The anode assembly (5) includes: an anode element (501) for transmitting electrons; and a second catalyst element (502) loaded on the surface of the anode element (501) for connecting with groundwater containing the pollutants. A proton exchange membrane (6) is fixed at the second through hole and is used to transfer protons in the first cavity to the second sieve segment (102) without other solute exchange. The detection component (7) is disposed in the first cavity and / or the second sieve section (102). The detection component (7) is electrically connected to the water injection component (2) and is used to adjust the output power of the water injection component (2) according to the detection value.

2. The groundwater circulating well galvanic cell repair device based on biochar electrode according to claim 1, characterized in that, The cathode (401) and / or the anode (501) are composed of columnar and sheet-like structures; And / or, the cathode (401) and / or the anode (501) are made of graphite material; And / or, the first catalyst (402) and / or the second catalyst (502) are made of biochar material.

3. The groundwater circulating well galvanic cell repair device based on biochar electrode according to claim 1, characterized in that, The detection component (7) includes: The first detection element is disposed in the first cavity and is used to detect the liquid concentration in the first cavity; And / or, a second detection element, disposed within the second sieve section (102), for detecting the liquid concentration within the second sieve section (102).

4. The groundwater circulating well galvanic cell repair device based on biochar electrode according to any one of claims 1 to 2, characterized in that, The groundwater circulation well galvanic cell repair device based on biochar electrodes includes: The first storage unit (8) stores the oxidant and / or electrolyte, and the first storage unit (8) is in communication with the first cavity for supplying the oxidant and / or electrolyte into the first cavity; And / or, the second storage unit (9) is in communication with the first cavity for recovering the electrolyte in the first cavity; And / or, a packer (10) is fixed inside the circulation well body (1) to separate the first screen section (101) and the second screen section (102).

5. The groundwater circulating well galvanic cell repair device based on biochar electrode according to claim 4, characterized in that, The first cavity is provided with a stirring element (11) for accelerating the dissolution of the oxidant and / or the electrolyte; And / or, the proton exchange membrane (6) has an anti-deposition layer on the surface near the second sieve segment (102).

6. The groundwater circulating well galvanic cell repair device based on biochar electrode according to claim 5, characterized in that, The first storage unit (8) is connected to the first cavity through a pipe (12), and the stirring element (11) is located at the end of the pipe (12) away from the first storage unit (8).

7. The groundwater circulating well galvanic cell repair device based on biochar electrode according to any one of claims 1 to 2, characterized in that, Along the length extension direction of the circulating well body (1), the size of the liquid storage component (3) is smaller than the size of the second screen section (102); And / or, the liquid storage component (3) is detachably fixed to the circulation well body (1); And / or, the liquid storage component (3) is provided with a loading and unloading guide structure (301) above it.

8. A method for remediating galvanic cells in groundwater circulating wells based on biochar electrodes, applied to the biochar electrode-based galvanic cell remediation device for groundwater circulating wells according to any one of claims 1 to 7, characterized in that, include: The groundwater enters the first screen section (101) through the inlet (1011); The groundwater is pumped into the second screen section (102) through the pumping unit (2); The cathode assembly (4) is connected to a solution containing the oxidant, and the anode assembly (5) is connected to groundwater containing the pollutant; Electrons in the pollutants are transferred to the oxidant, and protons in the first cavity are transported to the second sieve section (102) through the proton exchange membrane (6), forming a current loop with the electron transfer to achieve the degradation of the pollutants; The degraded groundwater is discharged from the outlet (1021).

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