Preparation method of bionic electrochemical cathode and application of bionic electrochemical cathode in reductive degradation of perfluorinated compound

Abstract

The invention provides a preparation method of a bionic electrochemical cathode and application of the bionic electrochemical cathode in reductive degradation of perfluorinated compounds, and the preparation method comprises the following steps: mixing a bionic enzyme material with single-layer graphene oxide to obtain a loading solution; and dispensing the load liquid on a hydrophilic carbon paper substrate to obtain the bionic enzyme modified electrode. The biomimetic enzyme modified electrode and the reference electrode are inserted into the electrolyte of the cathode chamber of the reactor, the counter electrode is inserted into the electrolyte of the anode chamber of the reactor, and the perfluorinated compound is added into the cathode chamber. Electrifying the cathode and the anode, and performing electrochemical reduction degradation on the perfluorinated compound. Aiming at an anaerobic environment of underground water, an electrochemical bionic reduction method is adopted, and efficient defluorination can be realized under an anaerobic condition. Under low voltage such as-1.6 V, degradation of perfluorinated compounds can be achieved, the degradation rate can reach 89% or above, and the defluorination rate can reach 87% or above. And high-efficiency defluorination can be realized at neutral pH and 30 DEG C, no additional chemical reagent is needed, and no toxic by-product is generated.

Description

Technical Field

[0001] This invention relates to the field of electrochemical degradation technology, and in particular to a method for preparing a biomimetic electrochemical cathode and its application in the reduction and degradation of perfluorinated compounds. Background Technology

[0002] Perfluorinated compounds (PFAS) are a class of organofluorine compounds with extremely high environmental persistence, bioaccumulation, and potential toxicity. Due to their exceptional stability and unique hydrophobic and oleophobic properties, they are widely used in textiles, food packaging, coatings, and fire extinguishing agents. PFAS have been detected in wildlife and human organisms worldwide, with their main toxic effects including hepatotoxicity, immunotoxicity, hormone disruption, and increased cancer risk. Therefore, PFAS have become one of the most concerning pollutants globally, and many perfluorinated compounds have been regulated or listed in the Stockholm Convention's POPs list. The U.S. Environmental Protection Agency (USEPA) further reduced the recommended drinking water safety level for perfluorooctane sulfonate (PFOS) from 70 ng / L to 4 ng / L in 2024. Therefore, developing technologies for the efficient degradation of PFAS pollutants is crucial.

[0003] The carbon-fluorine (CF) bond energy in PFAS molecules is extremely high (approximately 485 kJ / mol), resulting in significant resistance to most traditional physical, chemical, and biological degradation processes. Currently, PFAS treatment technologies mainly fall into two categories: one is separation and concentration technologies (such as activated carbon adsorption and ion exchange), but this method only achieves phase transfer, failing to completely decompose pollutants and generating concentrated waste requiring further disposal; the other is degradation and destruction technologies, aiming to mineralize PFAS into harmless fluoride ions, carbon dioxide, and water. PFAS includes MeU-C6a, i.e., perfluoro-4-(trifluoromethyl)pent-2-enoic acid. Various degradation methods exist, such as chemical oxidation, electrochemical oxidation, chemical reduction, microbial methods, and photodegradation. These existing methods have different drawbacks. For example, physical adsorption only achieves the enrichment and transfer of pollutants and cannot degrade perfluorinated compounds. Chemical reduction methods have low MeU-C6a degradation rates, rely on strong reducing agents, are costly and unstable, and may cause secondary pollution. Photodegradation requires continuous light exposure, making it difficult to apply in practice to groundwater remediation.

[0004] In summary, there is an urgent need for a method for the efficient defluorination of MeU-C6a under anaerobic conditions, without producing toxic byproducts, and with mild reaction conditions. Summary of the Invention

[0006] To overcome the problems existing in related technologies, the purpose of this invention is to provide a method for preparing a biomimetic electrochemical cathode and its application in reducing and degrading perfluorinated compounds. This method has the advantages of efficient defluorination, mild reaction conditions, environmental friendliness, low energy consumption, green and harmless properties, and applicability to groundwater remediation scenarios.

[0007] A method for preparing a biomimetic electrochemical cathode, comprising: Clean the hydrophilic carbon paper substrate; A biomimetic enzyme material is mixed with monolayer graphene oxide to obtain a loading solution; wherein the biomimetic enzyme material is tetraphenylporphyrin cobalt. The loading liquid is drop-coated onto the hydrophilic carbon paper substrate to obtain a biomimetic enzyme-modified electrode; The biomimetic enzyme-modified electrode and the reference electrode are inserted into the electrolyte in the cathode chamber of the reactor, and the counter electrode is inserted into the electrolyte in the anode chamber of the reactor; wherein the reactor is an H-type electrolytic cell.

[0008] In a preferred embodiment of the present invention, the cleaning of the hydrophilic carbon paper substrate includes: Cut the hydrophilic carbon paper to adjust its size, and obtain the cut hydrophilic carbon paper; The cut hydrophilic carbon paper was soaked in acetone and removed after 2 hours to obtain the soaked hydrophilic carbon paper. The soaked hydrophilic carbon paper was filtered and rinsed with ethanol to obtain rinsed hydrophilic carbon paper. The rinsed hydrophilic carbon paper is air-dried to obtain a hydrophilic carbon paper substrate.

[0009] In a preferred embodiment of the present invention, the step of mixing the biomimetic enzyme material with monolayer graphene oxide to obtain a loading solution includes: 4 mg of tetraphenylporphyrin cobalt was dissolved in 1 ml of N,N-dimethylformamide by ultrasonication to obtain a solution; Take 0.2 ml of the solution and add it to the injection bottle, then add 0.2 ml of monolayer graphene oxide with a concentration of 5 mg / ml, 0.6 ml of N,N-dimethylformamide and 50 μl of Nafion 117 to the injection bottle to obtain the initial mixture; The initial mixture is ultrasonically mixed to obtain the loaded liquid.

[0010] In a preferred embodiment of the present invention, the step of drop-coating the loading liquid onto the hydrophilic carbon paper substrate to obtain a biomimetic enzyme-modified electrode includes: 1 ml of the loading solution was evenly distributed into six drops on the front and back sides of the hydrophilic carbon paper substrate; wherein, the front side of the hydrophilic carbon paper substrate was dropped three times and the back side of the hydrophilic carbon paper substrate was dropped three times.

[0011] In a preferred embodiment of the present invention, the step of uniformly applying 1 ml of the loading liquid in six drops to the front and back sides of the hydrophilic carbon paper substrate includes: Each time the loading liquid is applied to the front or back of the hydrophilic carbon paper substrate, the following steps are included: A first hydrophilic carbon paper substrate is obtained by using a pipette to drop 166.6 μL of the loading liquid onto the front or back of the hydrophilic carbon paper substrate. The loading liquid on the first hydrophilic carbon paper substrate was evenly coated using a glass rod to obtain the second hydrophilic carbon paper substrate; The second hydrophilic carbon paper substrate was heated and dried under infrared light to obtain the third hydrophilic carbon paper substrate.

[0012] In a preferred embodiment of the present invention, before inserting the biomimetic enzyme-modified electrode and the reference electrode into the electrolyte in the cathode chamber of the reactor, the method further includes: The reactor is divided into a cathode chamber and an anode chamber using a cation exchange membrane. The biomimetic enzyme-modified electrode is fixed using an electrode clamp; The biomimetic enzyme-modified electrode, reference electrode, and counter electrode are electrically connected to the electrochemical workstation; the reference electrode is a silver / silver chloride electrode, and the counter electrode is a platinum sheet electrode.

[0013] In a preferred embodiment of the present invention, after dividing the reactor into a cathode chamber and an anode chamber using a cation exchange membrane, the method further includes: A first electrolyte is added to the cathode chamber. The first electrolyte consists of a 50 mmol / L phosphate buffer solution and a 5 mg / L perfluoro-4-(trifluoromethyl)pent-2-enoic acid (MeU-C6a) solution. The volume of the first electrolyte is 200 mL. A second electrolyte is added to the cathode chamber. The second electrolyte is a phosphate buffer solution with a concentration of 50 mmol / L and a volume of 200 mL.

[0014] The present invention also provides a method for preparing a biomimetic electrochemical cathode for the application of reducing and degrading perfluorinated compounds, wherein electricity is passed through the cathode chamber and anode chamber of the reactor to electrochemically degrade the perfluorinated compounds.

[0015] In a preferred embodiment of the present invention, before energizing the cathode and anode chambers of the reactor to electrochemically degrade the perfluorinated compound, the method further includes: N2 was continuously introduced into the cathode chamber of the reactor over 40 minutes to eliminate oxygen interference in the cathode chamber, and then the reactor was allowed to stand overnight.

[0016] In a preferred embodiment of the present invention, the step of energizing the cathode and anode chambers of the reactor to electrochemically degrade the perfluorinated compound includes: A constant -1.6V voltage is provided using an electrochemical workstation; Use a water bath to maintain the electrolyte temperature at 30°C and stir continuously at 300 rpm. 4 ml of cathodic electrolyte was sampled at 0, 1, 2, 4, 6, 8, 12 and 24 h respectively; The MeU-C6a concentration of the cathode electrolyte was detected; The concentration of fluoride ions generated after the reduction and degradation of MeU-C6a was detected using a fluoride ion electrode.

[0017] The beneficial effects of this invention are as follows: The present invention provides a method for preparing a biomimetic electrochemical cathode, comprising: cleaning a hydrophilic carbon paper substrate; mixing a biomimetic enzyme material with a single layer of graphene oxide to obtain a loading solution; wherein the biomimetic enzyme material is tetraphenylporphyrin cobalt; drop-coating the loading solution onto the hydrophilic carbon paper substrate to obtain a biomimetic enzyme-modified electrode; inserting the biomimetic enzyme-modified electrode and a reference electrode into the electrolyte in the cathode chamber of a reactor, and inserting the counter electrode into the electrolyte in the anode chamber of the reactor; wherein the reactor is an H-type electrolytic cell. Electricity is applied to the cathode and anode chambers of the reactor to electrochemically degrade perfluorinated compounds. First, the hydrophilic carbon paper is cut into 25×20 mm pieces, soaked in acetone for 2 hours, removed, rinsed with ethanol, and air-dried to obtain the hydrophilic carbon paper substrate. Next, tetraphenylporphyrin cobalt (CoTPP) is dissolved in N,N-dimethylformamide (DMF), and then ultrasonically dissolved and mixed uniformly with a single layer of graphene oxide to obtain the loading solution. Ultrasonic dissolution allows for rapid and thorough mixing of CoTPP and DMF. Then, using a pipette, 1 ml of the loading solution was evenly distributed six times onto the front and back surfaces of the hydrophilic carbon paper substrate, with three drops onto the front and three drops onto the back. After each drop, the solution was spread evenly with a glass rod and heated and dried under infrared light. The next operation was performed only after complete drying. This strategy effectively avoided the coffee ring effect caused by rapid solvent evaporation, ensuring the uniformity and stability of the catalyst layer. After six repeated operations, a biomimetic enzyme-modified electrode was obtained. The biomimetic enzyme-modified electrode was fixed with a platinum electrode clamp as the working electrode, a silver / silver chloride electrode as the reference electrode, and a platinum electrode as the counter electrode. The biomimetic enzyme-modified electrode and the silver / silver chloride electrode were inserted into the electrolyte in the cathode chamber of the reactor, and the platinum electrode was inserted into the electrolyte in the anode chamber. Then, an energizer was applied to the cathode and anode chambers of the reactor at -1.6 V to conduct a defluorination experiment, electrochemically degrading perfluorinated compounds. This invention targets the anaerobic environment of groundwater, utilizing the susceptibility of perfluorinated compounds to nucleophilic attack at the Co sites of dehalogenases. It achieves highly efficient degradation of perfluorinated compounds through an electrochemical biomimetic reduction method, enabling efficient defluorination under anaerobic conditions. Degradation of perfluorinated compounds can be achieved at relatively low voltages, such as -1.6V, with degradation rates exceeding 89% and defluorination rates exceeding 87%. Efficient defluorination can be achieved at neutral pH and 30°C, without the need for additional chemical reagents and without producing toxic byproducts. Attached Figure Description

[0018] Figure 1 This is a flowchart of the preparation method of the biomimetic electrochemical cathode of the present invention; Figure 2 This is a line graph showing the degradation rate of MeU-C6a over time at a voltage of -1.6 V according to the present invention. Figure 3 This is a line graph showing the defluorination rate of MeU-C6a over time at a voltage of -1.6 V according to the present invention. Figure 4 This is a scanning electron microscope image of the biomimetic enzyme-modified electrode of the present invention. Detailed Implementation

[0020] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make the invention more thorough and complete, and to fully convey the scope of the invention to those skilled in the art.

[0021] Example 1 like Figure 1 As shown, this embodiment provides a method for preparing a biomimetic electrochemical cathode, including: S1: Clean the hydrophilic carbon paper substrate; S2: The biomimetic enzyme material is mixed with monolayer graphene oxide to obtain a loading solution; wherein the biomimetic enzyme material is tetraphenylporphyrin cobalt; S3: The loading liquid is drop-coated onto the hydrophilic carbon paper substrate to obtain a biomimetic enzyme-modified electrode; S4: Insert the biomimetic enzyme-modified electrode and the reference electrode into the electrolyte in the cathode chamber of the reactor, and insert the counter electrode into the electrolyte in the anode chamber of the reactor; wherein the reactor is an H-type electrolytic cell.

[0022] Microbial reductive dehalogenation is essentially the process by which certain anaerobic microorganisms, under anaerobic conditions, utilize halogenated organic compounds (such as chloroform, tetrachloroethylene (PCE), and polychlorinated biphenyls (PCBs)) as electron acceptors to obtain energy for growth, while simultaneously reducing toxic halogenated compounds to less toxic or harmless products. Inspired by microbial reductive dehalogenation, this invention employs dehalogenation enzyme activity factor VB... 12 Tetraphenylporphyrin cobalt (CoTPP), a biomimetic enzyme material with a similar structure, was composited with monolayer graphene oxide (GO) to prepare an electrode loading solution. This electrode loading solution was then modified onto carbon paper to obtain a biomimetic enzyme-modified electrode. The specific steps are as follows: The first step is to clean the hydrophilic carbon paper substrate, including the following steps: S11: Cut the hydrophilic carbon paper to adjust its size, and obtain the cut hydrophilic carbon paper; S12: Soak the cut hydrophilic carbon paper in acetone for 2 hours to obtain soaked hydrophilic carbon paper. S13: The soaked hydrophilic carbon paper is filtered and washed with ethanol to obtain washed hydrophilic carbon paper. S14: The rinsed hydrophilic carbon paper is air-dried to obtain a clean hydrophilic carbon paper substrate.

[0023] The hydrophilic carbon paper was cut to 25mm × 20mm. After cutting, the cut hydrophilic carbon paper was immersed in acetone for 2 hours. The purpose of this is to utilize the strong solubility of acetone to effectively remove hydrophobic organic impurities such as colloids and resins from the carbon fiber surface. This is a key pretreatment for achieving hydrophilization. After immersion, the immersed hydrophilic carbon paper was obtained. The immersed hydrophilic carbon paper was then rinsed using ethanol. This serves two purposes: first, to wash away residual acetone and dissolved impurities in the carbon paper pores; and second, to utilize the hydrophilic properties of ethanol and its miscibility with water, laying the foundation for subsequent aqueous phase treatment. After rinsing, the rinsed hydrophilic carbon paper was obtained. The rinsed hydrophilic carbon paper was then allowed to air dry at room temperature. Air drying was chosen to avoid surface structure changes or new hydrophobic effects that might be caused by high-temperature drying, thus ensuring a stable hydrophilic carbon paper substrate with durable hydrophilic properties.

[0024] Next, a loading solution is prepared, wherein the biomimetic enzyme material is mixed with monolayer graphene oxide to obtain the loading solution, comprising: S21: Dissolve 4 mg of tetraphenylporphyrin cobalt in 1 ml of N,N-dimethylformamide by ultrasonication to obtain a solution; S22: Add 0.2 ml of the solution to the injection bottle, and add 0.2 ml of monolayer graphene oxide with a concentration of 5 mg / ml, 0.6 ml of N,N-dimethylformamide and 50 μl of Nafion 117 to the injection bottle to obtain the initial mixture; S23: The initial mixture is ultrasonically mixed to obtain a loaded liquid.

[0025] 4 mg of cobalt tetraphenylporphyrin (CoTPP) was dissolved in 1 ml of N,N-dimethylformamide (DMF). N,N-dimethylformamide (DMF) is an excellent aprotic polar solvent with good solubility for many organometallic compounds, effectively solubilizing CoTPP molecules. Since CoTPP molecules readily aggregate, an ultrasonic-assisted dissolution process was employed. This utilizes the ultrasonic cavitation effect to effectively disperse the aggregates and accelerate the solubilization process, ensuring rapid and thorough mixing of CoTPP and DMF, ultimately yielding a homogeneous CoTPP / DMF solution. 0.2 ml of the solution was added to a 2 ml sample vial, followed by 0.2 ml of 5 mg / ml monolayer graphene oxide, 0.6 ml of N,N-dimethylformamide (DMF), and 50 μl of Nafion 117. After ultrasonic dissolution and homogenization for 1 hour, the loaded solution was obtained.

[0026] Then, the fabrication of the biomimetic enzyme-modified electrode begins, wherein the loading solution is drop-coated onto the hydrophilic carbon paper substrate to obtain the biomimetic enzyme-modified electrode, comprising: S31: Divide 1 ml of the loading solution into six equal portions and drop it onto the front and back sides of the hydrophilic carbon paper substrate; wherein, the front side of the hydrophilic carbon paper substrate is dropped three times and the back side of the hydrophilic carbon paper substrate is dropped three times.

[0027] S32: The step of evenly dispensing 1 ml of the loading solution into the front and back sides of the hydrophilic carbon paper substrate in six portions includes: Each time the loading liquid is applied to the front or back of the hydrophilic carbon paper substrate, the following steps are included: A first hydrophilic carbon paper substrate is obtained by using a pipette to drop 166.6 μL of the loading liquid onto the front or back of the hydrophilic carbon paper substrate. The loading liquid on the first hydrophilic carbon paper substrate was evenly coated using a glass rod to obtain the second hydrophilic carbon paper substrate; The second hydrophilic carbon paper substrate was heated and dried under infrared light to obtain the third hydrophilic carbon paper substrate.

[0028] Using a pipette, 1 ml of the loading solution was evenly divided into six portions, each 166.6 μL, and dropped onto a hydrophilic carbon paper substrate. The pipette allows for precise control of the loading solution, and the fractional dropping method avoids the coffee ring effect and achieves uniform coverage. The coffee ring effect occurs when a drop of solution is placed on a substrate and dries; because the evaporation rate at the edge of the droplet is much higher than at the center, the liquid flows outward to compensate for the loss at the edge. This process carries solutes (such as catalyst particles) from the solution and deposits them at the contact boundary of the droplet, forming a thick, uneven ring-shaped mark, while the central area is very thin or even nonexistent. During the dropping process, three drops were first placed on the front side of the hydrophilic carbon paper substrate, then the substrate was flipped over, and three more drops were placed on the back side. After each drop, the mixture was spread evenly with a glass rod and heated and dried under infrared light (60–70 °C, 10–15 min). After complete drying, the next drop was placed. During the first drop coating, a small amount of solution spreads on the carbon paper surface, forming a thin liquid film. After the solvent evaporates, the catalyst particles are initially fixed on the fiber surface and pores of the carbon paper. During the second drop coating, new droplets spread on the surface that already has a catalyst substrate layer. This changes the surface's hydrophilicity / hydrophobicity and roughness, making the subsequent droplet spreading more uniform and less prone to forming large droplets and significant flow. After three drop coatings on the front and back sides of the hydrophilic carbon paper substrate, the loading solution is more uniformly distributed on the hydrophilic carbon paper substrate, ultimately yielding a biomimetic enzyme-modified electrode. An electron microscope image of the biomimetic enzyme-modified electrode is shown below. Figure 4 As shown.

[0029] The method for preparing a biomimetic electrochemical cathode provided in this embodiment includes cleaning a hydrophilic carbon paper substrate, mixing a biomimetic enzyme material with a single layer of graphene oxide to obtain a loading solution; wherein the biomimetic enzyme material is tetraphenylporphyrin cobalt; drop-coating the loading solution onto the hydrophilic carbon paper substrate to obtain a biomimetic enzyme-modified electrode; inserting the biomimetic enzyme-modified electrode and a reference electrode into the electrolyte in the cathode chamber of the reactor, and inserting the counter electrode into the electrolyte in the anode chamber of the reactor; wherein the reactor is an H-type electrolytic cell. Electricity is applied to the cathode and anode chambers of the reactor to electrochemically degrade perfluorinated compounds. First, the hydrophilic carbon paper is cut into 25×20 mm pieces, soaked in acetone for 2 hours, removed, rinsed with ethanol by vacuum filtration, and air-dried to obtain a hydrophilic carbon paper substrate. Next, tetraphenylporphyrin cobalt (CoTPP) is dissolved in N,N-dimethylformamide (DMF), and then ultrasonically dissolved and mixed uniformly with a single layer of graphene oxide to obtain a loading solution. Ultrasonic dissolution allows for rapid and thorough mixing of CoTPP and DMF. Finally, using a pipette, 1 ml of the loading solution was evenly distributed into six portions on the front and back surfaces of the hydrophilic carbon paper substrate, with three portions on the front and three on the back. After each distribution, the solution was spread evenly with a glass rod and heated and dried under infrared light. The next operation was performed only after complete drying. This strategy effectively avoided the coffee ring effect caused by rapid solvent evaporation, ensuring the uniformity and stability of the catalyst layer. After six repeated operations, a biomimetic enzyme-modified electrode was obtained. The biomimetic enzyme-modified electrode was fixed with a platinum electrode clamp as the working electrode, a silver / silver chloride electrode as the reference electrode, and a platinum electrode as the counter electrode. The biomimetic enzyme-modified electrode and the silver / silver chloride electrode were inserted into the electrolyte in the cathode chamber of the reactor, and the platinum electrode was inserted into the electrolyte in the anode chamber. Then, an electric current was applied to the cathode and anode chambers of the reactor at -1.6 V to conduct a defluorination experiment, electrochemically degrading perfluorinated compounds. This invention targets the anaerobic environment of groundwater, utilizing the susceptibility of perfluorinated compounds to nucleophilic attack at the Co sites of dehalogenases. It achieves highly efficient degradation of perfluorinated compounds through an electrochemical biomimetic reduction method, enabling efficient defluorination under anaerobic conditions. Degradation of perfluorinated compounds can be achieved at relatively low voltages, such as -1.6V, with degradation rates exceeding 89% and defluorination rates exceeding 87%. Efficient defluorination can be achieved at neutral pH and 30°C, without the need for additional chemical reagents and without producing toxic byproducts.

[0030] Example 2 This embodiment provides a method for preparing a biomimetic electrochemical cathode. Based on Example 1, this embodiment describes the differences between Example 1 and Example 1. The method includes: S1: Clean the hydrophilic carbon paper substrate; S2: The biomimetic enzyme material is mixed with monolayer graphene oxide to obtain a loading solution; wherein the biomimetic enzyme material is tetraphenylporphyrin cobalt; S3: The loading liquid is drop-coated onto the hydrophilic carbon paper substrate to obtain a biomimetic enzyme-modified electrode; S4: Insert the biomimetic enzyme-modified electrode and the reference electrode into the electrolyte in the cathode chamber of the reactor, and insert the counter electrode into the electrolyte in the anode chamber of the reactor; wherein the reactor is an H-type electrolytic cell.

[0031] Before inserting the biomimetic enzyme-modified electrode and the reference electrode into the electrolyte in the cathode chamber of the reactor, the method further includes: S31': The reactor is divided into a cathode chamber and an anode chamber using a cation exchange membrane; S32': The biomimetic enzyme-modified electrode is fixed using an electrode clamp; S33': Connect the biomimetic enzyme-modified electrode, reference electrode, and counter electrode to the electrochemical workstation; the reference electrode is a silver electrode or a silver chloride electrode, and the counter electrode is a platinum sheet electrode.

[0032] The reference electrode is a silver electrode or a silver chloride electrode, and the counter electrode is a platinum sheet electrode. The silver / silver chloride electrode is made of porous metallic silver coated with silver chloride, immersed in a solution containing Cl... - The Ag / AgCl electrode, constructed in a solution, exhibits very low solubility, extremely high stability, and reversibility in high-temperature, high-pressure aqueous solutions. Furthermore, its surface remains well protected even in the presence of hydrogen. The reference electrode serves as the standard electrode in electrochemical measurements, its core function being to provide a stable and known reference potential for the working electrode, thereby ensuring the accuracy of the measurement results.

[0033] After dividing the reactor into a cathode chamber and an anode chamber using a cation exchange membrane, the process further includes: A first electrolyte is added to the cathode chamber. The first electrolyte consists of a 50 mmol / L phosphate buffer solution and a 5 mg / L perfluoro-4-(trifluoromethyl)pent-2-enoic acid (MeU-C6a) solution. The volume of the first electrolyte is 200 mL. A second electrolyte is added to the cathode chamber. The second electrolyte is a phosphate buffer solution with a concentration of 50 mmol / L and a volume of 200 mL.

[0034] An H-type electrolytic cell was used as the reactor, divided into a cathode chamber and an anode chamber by a cation exchange membrane. The main structure of the H-type electrolytic cell resembles the letter H, and it is a two-chamber electrolytic cell primarily used to physically isolate the products in the cathode and anode chambers, preventing them from reacting with each other. The reactor includes a cathode chamber, an anode chamber, and a cation exchange membrane. The cation exchange membrane is the channel connecting the cathode and anode chambers, allowing only cations to pass through to conduct the circuit while preventing rapid mixing of the solutions on both sides. Before the defluorination experiment, a first electrolyte was added to the cathode chamber, consisting of a 50 mmol / L phosphate buffer solution and a 5 mg / L perfluoro-4-(trifluoromethyl)pent-2-enoic acid (MeU-C6a) solution. A second electrolyte, also a 50 mmol / L phosphate buffer solution, was added to the anode chamber. The volume of both the first and second electrolytes was 200 mL. Next, the biomimetic enzyme-modified electrode was fixed with a platinum electrode clip as the working electrode, the platinum electrode as the counter electrode, and the silver / silver chloride electrode as the reference electrode. The working electrode is where the target electrochemical reaction occurs. The counter electrode provides a closed loop for the current flowing through the working electrode and undertakes auxiliary reactions. The reference electrode provides a stable, known, and constant electrode potential as a benchmark for measuring the working electrode potential, primarily used for precise measurement and control of the working electrode's potential relative to it. Then, the silver / silver chloride electrode, platinum electrode, and platinum electrode clip were electrically connected to an electrochemical workstation. The electrochemical workstation can precisely control the electrode potential or current and simultaneously and accurately measure the response signal of another variable. Finally, the silver / silver chloride electrode and platinum electrode clip were inserted into the electrolyte in the cathode chamber, and the platinum electrode was inserted into the electrolyte in the anode chamber. The reference electrode was placed close to the platinum electrode clip, with the platinum electrode and clip facing each other.

[0035] This embodiment uses an H-type electrolytic cell as the reactor. A cation exchange membrane divides the reactor into a cathode chamber and an anode chamber, physically isolating the products in the cathode and anode chambers to prevent mutual reaction. A biomimetic enzyme-modified electrode is fixed with a platinum electrode clamp as the working electrode, the platinum electrode as the counter electrode, and a silver / silver chloride electrode as the reference electrode. First, the silver / silver chloride electrode, platinum electrode, and platinum electrode clamp are electrically connected to the electrochemical workstation. Then, the silver / silver chloride electrode and platinum electrode clamp are inserted into the electrolyte in the cathode chamber, and the platinum electrode is inserted into the electrolyte in the anode chamber. Before the experiment, high-purity nitrogen (N2) is continuously purged into the cathode chamber of the reactor for at least 40 minutes to completely remove dissolved oxygen. Subsequently, the reactor is sealed under N2 atmosphere and allowed to stand overnight to ensure the system reaches physical and electrochemical equilibrium.

[0036] Example 3 This embodiment provides the application of the biomimetic electrochemical cathode preparation method of Embodiments 1 and 2 in the reduction and degradation of perfluorinated compounds. After step S4, electricity is supplied to the cathode chamber and anode chamber of the reactor to electrochemically degrade the perfluorinated compounds.

[0037] Prior to energizing the cathode and anode chambers of the reactor to electrochemically degrade the perfluorinated compound, the process further includes: N2 was continuously introduced into the cathode chamber of the reactor over 40 minutes to eliminate oxygen interference in the cathode chamber, and then the reactor was allowed to stand overnight.

[0038] Before conducting the defluorination experiment, nitrogen (N2) gas was continuously bubbled into the cathode chamber of the reactor for 40 minutes to eliminate oxygen interference, followed by overnight settling. In electrochemical experiments, dissolved oxygen (O2) in the electrolyte is a very common source of interference, participating in electrode reactions and introducing unwanted background current. Nitrogen (N2) is a chemically inert gas and does not participate in electrode reactions itself. By continuously bubbling N2 gas into the cathode chamber, dissolved O2 is carried away and replaced, thus achieving efficient physical deoxygenation. Continuous 40-minute nitrogen (N2) bubbling ensures thorough deoxygenation. The subsequent overnight settling allows the agitated electrolyte and electrode interface to return to equilibrium and stability, ensuring the experiment begins in a homogeneous, oxygen-free, and stable state, thereby obtaining reliable and reproducible data. The electrochemical degradation of the perfluorinated compound by energizing the cathode and anode chambers of the reactor includes: S51: Uses an electrochemical workstation to provide a constant -1.6V voltage; S52: Use a water bath to maintain the electrolyte temperature at 30°C and stir continuously at 300 rpm. S53: Take 4 ml of cathodic electrolyte samples at 0, 1, 2, 4, 6, 8, 12 and 24 h respectively; S54: Detect the MeU-C6a concentration of the cathode electrolyte; S55: The concentration of fluoride ions generated after the degradation of MeU-C6a was detected using a fluoride ion electrode.

[0039] Defluorination experiments were conducted using a constant -1.6V voltage provided by an electrochemical workstation. The electrolyte temperature was maintained at 30℃ using a water bath, and the electrolyte was continuously stirred at 300 rpm. Samples of 4 ml of electrolyte were taken at 0, 1, 2, 4, 6, 8, 12, and 24 hours. The concentration of MeU-C6a in the catholyte was detected using high-resolution liquid chromatography-tandem triple quadrupole mass spectrometry (HPLC-MS / MS), and the concentration of fluoride ions generated after the reduction and degradation of MeU-C6a was detected using a fluoride ion electrode.

[0040] Figure 2This is a line graph showing the degradation rate of MeU-C6a over time at a voltage of -1.6 V, as described in this invention. Figure 3 This is a line graph showing the defluorination rate of MeU-C6a over time at a voltage of -1.6 V, as described in this invention. Figure 2 It can be seen that, compared to using GO (monolayer graphene oxide), COTPP (cobalt tetraphenylporphyrin), and VB alone, 12 +GO stands for dehalogenase active factor + monolayer graphene oxide. The CoTPP+GO prepared in this invention exhibits the lowest residual MeU-C6a content and the fastest rate of MeU-C6a degradation at 4h, 8h, 12h, 16h, 20h, and 24h, demonstrating that CoTPP+GO has the best degradation effect on MeU-C6a. Figure 3 It can be seen that the CoTPP+GO prepared in this invention exhibits the highest defluorination rate and the fastest rate of increase in defluorination rate at 4h, 8h, 12h, 16h, 20h, and 24h of degradation, proving that CoTPP+GO can effectively break the carbon-fluorine bonds in PFAS molecules. This invention uses DMF as a solvent, and CoTPP and GO form a complex through π-π stacking, thereby significantly improving the defluorination effect of CoTPP. VB 12 Its main purpose is comparison; CoTPP is based on VB. 12 Based on further structural optimization, both active sites are Co coordinated with N4, but CoTPP's defluorination effect is significantly better than VB. 12 .

[0041] This invention is designed for anaerobic groundwater environments. It utilizes the susceptibility of perfluorinated compounds to nucleophilic attack at the Co sites of dehalogenases to achieve highly efficient degradation of perfluorinated compounds via an electrochemical biomimetic reduction method. Degradation of perfluorinated compounds can be achieved at a relatively low voltage (-1.6 V), with a degradation rate exceeding 89% and a defluorination rate exceeding 87% within 24 hours.

[0042] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0043] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a biomimetic electrochemical cathode, characterized in that, The application relates to a method for preparing a biomimetic enzyme modified electrode, and belongs to the technical field of electrochemistry. The method comprises the following steps: washing a hydrophilic carbon paper substrate; mixing a biomimetic enzyme material with single-layer graphene oxide to obtain a loading solution; wherein the biomimetic enzyme material is cobalt tetraphenylporphyrin; dropping the loading solution on the hydrophilic carbon paper substrate to obtain a biomimetic enzyme modified electrode; 2. The method of claim 1, wherein the method comprises: inserting the biomimetic enzyme modified electrode and a reference electrode into electrolyte in a cathode chamber of a reactor, and inserting a counter electrode into electrolyte in an anode chamber of the reactor; wherein the reactor is an H-shaped electrolytic cell. The method for washing the hydrophilic carbon paper substrate comprises the following steps: cutting the hydrophilic carbon paper to adjust the size of the hydrophilic carbon paper to obtain cut hydrophilic carbon paper; immersing the cut hydrophilic carbon paper in acetone for 2 hours to obtain soaked hydrophilic carbon paper; performing suction filtration flushing on the soaked hydrophilic carbon paper by using ethanol to obtain flushed hydrophilic carbon paper; 3. The method of claim 1, wherein the method further comprises: air-drying the flushed hydrophilic carbon paper to obtain a clean hydrophilic carbon paper substrate. The method for mixing the biomimetic enzyme material with single-layer graphene oxide to obtain a loading solution comprises the following steps: ultrasonically dissolving 4 mg of cobalt tetraphenylporphyrin in 1 ml of N,N-dimethylformamide to obtain a dissolved solution; taking 0.2 ml of the dissolved solution into a sample bottle, and adding 0.2 ml of single-layer graphene oxide with a concentration of 5 mg / ml, 0.6 ml of N,N-dimethylformamide and 50 ul of Nafion 117 into the sample bottle to obtain an initial mixed solution; 4. The method of claim 1, wherein the method further comprises: ultrasonically mixing the initial mixed solution to obtain a loading solution. The method for dropping the loading solution on the hydrophilic carbon paper substrate to obtain a biomimetic enzyme modified electrode comprises the following steps:

5. The method of claim 4, wherein the method further comprises the step of: equally dividing 1 ml of the loading solution into six portions and dropping the loading solution on the front and back surfaces of the hydrophilic carbon paper substrate; wherein the front surface of the hydrophilic carbon paper substrate is dripped three times, and the back surface of the hydrophilic carbon paper substrate is dripped three times. The method for equally dividing 1 ml of the loading solution into six portions and dropping the loading solution on the front and back surfaces of the hydrophilic carbon paper substrate comprises the following steps: each time the loading solution is dropped on the front or back surface of the hydrophilic carbon paper substrate, the following steps are included: dropping 166.6 ul of the loading solution on the front or back surface of the hydrophilic carbon paper substrate by using a pipette to obtain a first hydrophilic carbon paper substrate; uniformly smearing the loading solution on the first hydrophilic carbon paper substrate by using a glass rod to obtain a second hydrophilic carbon paper substrate; 6. The method of claim 1, wherein the method further comprises: heating and drying the second hydrophilic carbon paper substrate under infrared light to obtain a third hydrophilic carbon paper substrate. Before the biomimetic enzyme modified electrode and the reference electrode are inserted into electrolyte in a cathode chamber of a reactor, the following steps are further included: dividing the reactor into a cathode chamber and an anode chamber by using a cation exchange membrane; fixing the biomimetic enzyme modified electrode by using an electrode clamp; 7. The method of claim 6, wherein the method further comprises the step of: electrically connecting the biomimetic enzyme modified electrode, the reference electrode and the counter electrode to an electrochemical workstation; the reference electrode is a silver / silver chloride electrode, and the counter electrode is a platinum sheet electrode. After the reactor is divided into the cathode chamber and the anode chamber by using the cation exchange membrane, the following steps are further included: A first electrolyte is added to the cathode chamber, the first electrolyte is composed of phosphate buffer solution with a concentration of 50 mmol / L and perfluoro-4-(trifluoromethyl)pent-2-enoic acid (MeU-C6a) solution with a concentration of 5 mg / L, the volume of the first electrolyte is 200 mL; A second electrolyte is added to the cathode chamber, the second electrolyte is composed of phosphate buffer solution with a concentration of 50 mmol / L, the volume of the second electrolyte is 200 mL.

8. Use of the method for the preparation of a biomimetic electrochemical cathode according to any one of claims 1 to 7 for the reductive degradation of perfluorinated compounds, characterized in that, The cathode chamber and the anode chamber of the reactor are powered to electrochemically degrade the perfluorinated compound.

9. Use according to claim 8, characterized in that, Before the cathode chamber and the anode chamber of the reactor are powered to electrochemically degrade the perfluorinated compound, the method further comprises: N2 is continuously introduced into the cathode chamber of the reactor within 40 min to eliminate the interference of oxygen in the cathode chamber, and then it is left overnight.

10. Use according to claim 8, characterized in that, The cathode chamber and the anode chamber of the reactor are powered to electrochemically degrade the perfluorinated compound, comprising: A constant-1.6V voltage is provided by using an electrochemical workstation; The temperature of the electrolyte is maintained at 30℃ by using a water bath, and the electrolyte is continuously stirred at a speed of 300 rpm; 4 ml of cathode electrolyte is sampled at 0, 1, 2, 4, 6, 8, 12 and 24 h respectively; The MeU-C6a concentration of the cathode electrolyte is detected; The fluoride ion concentration generated after the reductive degradation of MeU-C6a is detected by using a fluoride ion electrode.

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