Electrode material for electrochemical oxidation treatment of organic wastewater and preparation method thereof

Abstract

This invention provides an electrode material and its preparation method for electrochemical oxidation treatment of organic wastewater. The electrode material comprises a titanium substrate, a titanium carbide transition layer, and a graphene active layer. The titanium carbide transition layer is in situ bonded to the surface of the titanium substrate, and the graphene active layer is in situ bonded to the surface of the titanium carbide transition layer. The titanium carbide transition layer is a dense layer formed by the diffusion reaction of carbon atoms into the titanium substrate. Acting as a "molecular bridge," the titanium carbide transition layer achieves a gradient transition of chemical bonding from the titanium substrate (metallic bonds) to graphene (covalent bonds). The graphene active layer can be single-layered or multi-layered. This invention fundamentally solves the problems of poor bonding and easy detachment of graphene from the titanium substrate by constructing a unique gradient interface structure.

Description

Technical Field

[0001] This invention belongs to the technical field of electrode materials for electrochemical oxidation treatment of organic wastewater, and particularly relates to an electrode material for electrochemical oxidation treatment of organic wastewater and its preparation method. Background Technology

[0002] With the rapid development of industries such as pharmaceuticals and chemicals, the treatment of recalcitrant organic wastewater, especially mixed wastewater containing antibiotics such as penicillin, erythromycin, and cephalosporins, has become a severe environmental challenge. This type of wastewater is complex in composition, highly toxic to organisms, and has poor biodegradability, making traditional biological treatment methods often inefficient. Electrochemical advanced oxidation technology, due to its strong oxidizing capacity, ease of operation, and environmental friendliness, is considered a highly promising advanced treatment technology.

[0003] Electrode materials are the core of electrochemical oxidation technology. Titanium-based metal oxide electrodes (such as DSA) are widely used due to their good chemical stability, but their conductivity, electrocatalytic activity, and specific surface area are limited. Graphene, as an ideal two-dimensional carbon material, has extremely high conductivity, a very large specific surface area, and excellent chemical stability, making it a highly promising electrode modification material.

[0004] However, current technologies for loading graphene onto titanium substrates face fundamental challenges. Most mainstream methods employ physical coating techniques (such as spin coating, spray coating, and electrophoretic deposition) to attach pre-prepared graphene oxide or graphene sheets to the titanium surface, followed by reduction treatment. However, the graphene layers obtained by these methods peel off over a large area within a short time, leading to a sharp decline in electrode performance. Another method commonly uses vapor deposition to grow graphene coatings on titanium substrates, but the resulting graphene coatings also have a short lifespan, especially when used to treat high-concentration saline organic wastewater, where the graphene coating easily detaches.

[0005] Therefore, developing an electrode material with excellent conductivity, high electrocatalytic activity, and long-term stable operation is key to advancing the practical application of this technology. Summary of the Invention

[0006] In view of this, the present invention provides an electrode material for electrochemical oxidation treatment of organic wastewater and a method for preparing the same, thereby increasing the lifespan of the electrode by improving the treatment of the titanium substrate and constructing a unique gradient interface structure.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: The first aspect of this invention provides a method for preparing an electrode material for electrochemical oxidation treatment of organic wastewater. The organic wastewater contains a high concentration of salt. The electrode material sequentially comprises a titanium substrate, a titanium carbide transition layer, and a graphene active layer, all layered and bonded together. The titanium carbide transition layer is in situ bonded to the surface of the titanium substrate, and the graphene active layer is in situ bonded to the surface of the titanium carbide transition layer. The titanium carbide transition layer is a dense layer formed by the diffusion reaction of carbon atoms into the titanium substrate. As a "molecular bridge," the titanium carbide transition layer realizes a gradient transition of chemical bonding from the titanium substrate (metallic bonds) to graphene (covalent bonds). The graphene active layer is a single layer or multiple layers of graphene, such as 1-2 layers, 3-5 layers, etc. Multiple graphene layers further reduce the internal stress of the film and improve the coating life. The electrode material is prepared by the following method: S1: Pretreatment of the titanium substrate: chemical etching and shot blasting, wherein the shot blasting is specifically performed by using G80 cast steel sand to blast the surface of the etched titanium substrate. S2: The pretreated titanium substrate is subjected to high-temperature reduction and activation treatment; S3: Using vapor deposition technology, carbon source gas is introduced into a vacuum furnace to generate a titanium carbide transition layer and a graphene active layer in situ.

[0008] In a preferred embodiment of the first aspect of the present invention, the microstructure of the graphene active layer is continuous and densely wrinkled. When the wrinkled graphene active layer is applied to the electrochemical oxidation treatment of organic wastewater, the wrinkles increase the surface area in contact with water, thereby increasing the reaction area and thus improving the reaction efficiency.

[0009] In a preferred embodiment of the first aspect of the present invention, the thickness of the titanium carbide transition layer is 50-500 nm, more preferably 100-350 nm.

[0010] In a preferred embodiment of the first aspect of the present invention, the high-temperature reduction activation treatment in step S2 is as follows: the pretreated titanium substrate is placed in a vacuum furnace, and under an inert protective atmosphere, the temperature is gradually increased to 800-1200℃ at a rate of 5-20℃ / min. Gradually increasing the temperature is beneficial for uniform heating of the coating. If the temperature rises too quickly and suddenly, due to thermal expansion and contraction, uneven heating of the coating is likely to occur, i.e., the temperature difference between the surface and the underlying layer is greater. During the heating process, the surface volume is likely to be larger than the actual coating volume. This will lead to greater surface shrinkage and less underlying shrinkage during cooling, which will easily cause fine cracks on the surface and affect the electrode life. Therefore, the temperature is gradually increased at a rate of 5-20℃ / min. Then, a reducing gas is introduced to perform reduction activation treatment on the surface of the titanium substrate for 10-60 minutes.

[0011] In a preferred embodiment of the first aspect of the present invention, the reducing gas is hydrogen or a mixture of hydrogen and an inert gas.

[0012] In a preferred embodiment of the first aspect of the present invention, in step S3, the titanium substrate is kept in a vacuum furnace, and carbon source gas is introduced into the vacuum furnace at a flow rate of 10-100 mL / min (sccm). The carbon source gas is introduced alternately, and the deposition temperature is 800-1200℃. In order to obtain a multilayer graphene film during the deposition process, a layer-by-layer deposition method is adopted, with the carbon source gas introduced alternately for 15-20 min, then the introduction of carbon source gas is stopped, and the vacuum furnace temperature is lowered to 300-400℃. After the deposited film has solidified, the temperature is then raised to the deposition temperature of 800-1200℃. The process involves introducing carbon source gas for 15-20 minutes, then lowering the vacuum furnace temperature to 300-400℃ to solidify the film. This cycle is repeated to obtain multilayer graphene films. Two cycles produce two graphene films, and three cycles produce three graphene films. The first introduction of carbon source gas takes longer than subsequent introductions. During the first introduction, under high temperature, some of the active carbon atoms generated by the carbon source gas decomposition penetrate into the surface of the titanium substrate and react with titanium atoms to form a titanium carbide transition layer in situ. The other part nucleates and grows epitaxially on the surface of the newly formed titanium carbide transition layer to form a graphene layer. After thin film deposition is completed, the carbon source gas and reducing gas are stopped, and the system is cooled under an inert protective atmosphere.

[0013] According to a preferred embodiment of the first aspect of the present invention, the carbon source gas is one or more of methane, ethylene, or acetylene.

[0014] In a preferred embodiment of the first aspect of the present invention, the chemical etching in step S1 specifically involves: mechanically polishing the titanium substrate, followed by chemical etching in an acidic etching solution to completely remove the surface oxide layer and obtain a micro-rough structure, and then cleaning and drying it for later use. The acid etching solution is a mixed aqueous solution of hydrofluoric acid and nitric acid, wherein the volume fraction of hydrofluoric acid is 1-10%, the volume fraction of nitric acid is 5-30%, the etching time is 3-30 minutes, and the etching temperature is 20-60℃. A second aspect of the invention provides an electrode material for electrochemical oxidation treatment of organic wastewater. The electrode material sequentially comprises, in a layered manner: a titanium substrate, a titanium carbide transition layer, and a graphene active layer. The titanium carbide transition layer is a dense layer formed by the diffusion reaction of carbon atoms into the titanium substrate. The graphene active layer is a single layer or multiple layers of graphene, and the microstructure of the graphene active layer is wrinkled. This electrode material is used as an anode for the electrochemical oxidation treatment of recalcitrant organic wastewater, especially high-salt recalcitrant organic wastewater. The organic wastewater contains recalcitrant organic pollutants, more preferably, it is a mixed pharmaceutical wastewater containing one or more of penicillin, macrolides (such as erythromycin), and cephalosporin antibiotics.

[0015] The current density of the electrochemical oxidation treatment is 5-50 mA / cm². 2 .

[0016] Because of the above technical solutions, this invention has the following advantages and positive effects compared with the prior art: Revolutionary interfacial bonding: In the first aspect of this invention, the titanium substrate is chemically etched to remove the surface oxide layer and shot peening is performed, resulting in a uniform micro-pit structure or micro-crack network on the surface, which increases the surface roughness of the substrate. The micro-pit structure increases the contact area between the coating and the substrate, and the coating can penetrate into the micro-cracks and pits, so that the coating and the substrate form a mechanical lock, forming an "anchoring effect" and increasing the bonding force between the coating and the substrate. Secondly, the pretreated titanium substrate undergoes high-temperature activation treatment to reduce internal stress in the coating and prevent micro-cracks within the coating. Thirdly, a titanium carbide transition layer exists between the titanium substrate and the graphene active layer. This transition layer is a dense layer formed by the diffusion reaction of carbon atoms into the titanium substrate, thus increasing the bonding force between the titanium substrate and the graphene active layer. Simultaneously, this invention uses a one-step CVD method to simultaneously generate the titanium carbide transition layer and the graphene active layer in situ, forming a "Ti-TiC-Graphene" gradient chemical bonding interface. The titanium carbide transition layer is metallurgically bonded to the titanium substrate and covalently bonded (CC) to the graphene active layer, thereby firmly "locking" the coating to the substrate. Fourthly, the graphene active layer has multiple graphene layers, and the multi-layer interface reduces internal stress. Cross-cut adhesion testing showed the coating adhesion reaches the highest level, 5B; under harsh oxygen evolution conditions (>10 hours), no visible peeling of the coating occurred. The above treatments reduce the internal stress of the overall coating and prevent micro-cracks. Therefore, when applied to the treatment of high-salt organic wastewater, this prevents salt from penetrating into the coating and causing internal cracks, thus increasing the coating's lifespan.

[0017] Superior electrochemical performance: The graphene layer provides extremely high conductivity and a huge specific surface area, which significantly reduces the charge transfer resistance of the electrode (more than 90% lower than that of traditional DSA electrodes) and greatly increases the electrochemical active area (more than 50 times higher). At the same time, the presence of the titanium carbide transition layer increases the oxygen evolution potential of the electrode, which is beneficial for directing the current efficiency towards the direct or indirect oxidation of organic matter.

[0018] Highly efficient wastewater treatment capabilities and exceptional stability: This composite electrode exhibits high degradation efficiency and rapid rate of target pollutants when treating high-concentration mixed antibiotic wastewater. More importantly, thanks to its excellent interfacial bonding, the electrode demonstrates extremely high stability during long-term continuous operation; the active layer does not detach, the substrate does not corrode, the treatment effect decays very slowly, and its service life far exceeds that of electrodes prepared by traditional coating methods or single-layer graphene.

[0019] The preparation process is simple and controllable: The method of this invention integrates the growth of the transition layer and the active layer into a one-step CVD process, eliminating the need for complex subsequent treatments. The process flow is simple and easy to scale up for production. By adjusting parameters such as temperature, gas flow rate, and time, the thickness of the TiC layer and the number and quality of graphene layers can be precisely controlled. Attached Figure Description

[0020] Figure 1 This is a scanning electron microscope image of the surface of the titanium-based in-situ grown graphene composite film prepared in Example 1 of the present invention. Figure 2 The images shown are (a) and (b) of the surface morphology after substrate pretreatment and film deposition, respectively, in Example 1 of this invention. Figure 3 The images shown are (a) a photograph of the surface morphology of the substrate and (b) a photograph of the morphology after film deposition in Comparative Example 3 of the present invention. Detailed Implementation

[0021] Analysis revealed that physical coating methods (such as spin coating, spray coating, and electrophoretic deposition) rely solely on weak physical adsorption or van der Waals forces. During the electrochemical reaction, the intensely generated gases (such as O2) on the electrode surface continuously impact the coating, causing the graphene layer to peel off over a large area in a short time. In contrast, vapor-phase deposition of graphene coatings results in increased internal stress and microcracks due to the rapid formation of a dense titanium dioxide insulating passivation layer on the titanium surface and a severe mismatch between the lattice constants of graphene and titanium. During the electrochemical reaction, salt from high-concentration organic wastewater easily penetrates these microcracks, leading to large-area detachment of the graphene coating and a shortened lifespan.

[0022] The method for preparing an electrochemical oxidation treatment of organic wastewater provided by this invention removes surface oxides from the titanium substrate and increases surface roughness to enhance the adhesion between the substrate and the coating through pretreatment; high-temperature reduction activation, deposition of a titanium carbide transition layer and a multilayer graphene coating, thereby reducing internal stress within the coating and reducing the occurrence of microcracks in the coating. Thus, when applied to the treatment of high-salt organic wastewater, it will not cause the graphene coating to fall off, increasing the coating's lifespan and achieving extremely high stability of the electrode material.

[0023] The electrode material for electrochemical oxidation treatment of organic wastewater and its preparation method, proposed in this invention, will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description.

[0024] Example 1

[0025] 1. Substrate Pretreatment: Take a TA1 industrial pure titanium plate with dimensions of 10mm × 10mm × 2mm. Grind its surface sequentially with 400-grit, 800-grit, and 1200-grit sandpaper until it achieves a mirror-like finish. Then, place it in a mixed acid solution consisting of 5% hydrofluoric acid and 10% nitric acid (by volume) and ultrasonically etch it at 40℃ for 5 minutes. After removal, ultrasonically clean it sequentially with deionized water, acetone, and ethanol for 10 minutes each to remove residual acid and organic matter. Finally, dry it with nitrogen gas for later use. Next, perform G80 cast steel shot blasting on the titanium plate surface. Shot blasting parameters: blasting pressure 0.4MPa, blasting angle 90 degrees, blasting distance 150mm, treatment time 30s.

[0026] 2. High-temperature reduction and activation: The pretreated titanium plate is placed in the quartz tube furnace of a tubular chemical vapor deposition furnace. High-purity argon gas (500 sccm) is introduced into the quartz tube furnace to purge the air. Then, under argon protection, the temperature is programmed to rise to 850℃ at a rate of 10℃ / min. After the temperature stabilizes, the gas is switched to an argon-hydrogen mixture (Ar:H2=200:50 sccm). This atmosphere and temperature are maintained for 30 minutes to fully reduce and activate the titanium surface.

[0027] 3. In-situ simultaneous CVD growth: Maintaining a temperature of 850℃, while keeping the total flow rate of the argon-hydrogen mixture constant, methane (CH4) is introduced into the quartz tube furnace as a carbon source at a flow rate of 30 sccm. After the deposition reaction continues for 20 minutes, the vacuum furnace temperature is lowered to 350℃ to solidify the deposited film. Then, the temperature is raised to the deposition temperature of 800-1200℃, and methane is introduced for 15 minutes. During this process, the carbon atoms generated by methane cracking simultaneously undergo two reactions: (a) infiltrating into the surface layer of the titanium substrate to form a titanium carbide (TiC) transition layer; (b) nucleating and growing a continuous graphene layer on the TiC layer.

[0028] 4. Cooling: After the reaction is complete, the methane and hydrogen gas lines are shut off. Under the protection of pure argon (500 sccm), the furnace body is allowed to cool naturally to room temperature. The sample is then removed, and a "Ti / TiC / graphene" composite film is obtained, which is denoted as sample S1.

[0029] Structural characterization: such as Figure 1 SEM revealed that the graphene layer was a continuous, uniform, wrinkled film. Cross-sectional TEM and EDS line scanning confirmed the presence of a TiC transition layer (approximately 200 nm thick) and the gradient distribution of carbon from the TiC layer to the graphene layer. The Raman spectrum showed a distinct 2D peak and a low D / G peak intensity ratio (I0.05). D / I G The value ≈0.15 indicates the high crystallinity of graphene.

[0030] Figure 2 The surface morphology of the titanium substrate before and after coating is shown. The surface after coating has irregular defects and pits.

[0031] Example 2

[0032] The difference from Example 1 lies in the parameters of steps 2 and 3: The deposition temperature was set to 900°C; the flow rate of methane was 20 sccm; the initial methane deposition time was 30 minutes; the vacuum furnace temperature was then lowered to 350°C to solidify the deposited film; the temperature was then raised to the deposition temperature of 800-1200°C; methane was introduced for 15 minutes; and then the film was cooled. The remaining steps were exactly the same as in Example 1.

[0033] The resulting sample is designated S2. Its TiC transition layer is relatively thin (approximately 100 nm), and it has two graphene active layers.

[0034] Example 3

[0035] The difference from Example 1 lies in the parameters of steps 2 and 3: The deposition temperature was set to 950°C; the methane flow rate was 50 sccm; and the deposition time was 10 minutes. The remaining steps were exactly the same as in Example 1, with methane gas circulated 5 times.

[0036] The resulting sample is designated S3. It has a relatively thick TiC transition layer (approximately 350 nm) and five graphene active layers.

[0037] Comparative Example 1 Take a titanium plate that has undergone the same pretreatment as in Example 1. A commercial graphene oxide (GO) aqueous solution (2 mg / mL) is uniformly drop-coated onto the surface of the titanium plate and dried at 60°C; this drop-coating is repeated three times to obtain a certain thickness. The coated titanium plate is then placed in a tube furnace and heat-treated at 450°C for 2 hours under argon protection to thermally reduce GO to reduced graphene oxide (rGO). The resulting sample is designated D1.

[0038] Comparative Example 2 (CVD method without hydrogen reduction activation step) A titanium plate with the same pretreatment as in Example 1 was used. It was placed in a CVD furnace and heated directly to 850°C under pure argon atmosphere. Without hydrogen reduction, methane (30 sccm) was directly introduced for deposition for 20 minutes, followed by cooling under an argon atmosphere. The resulting sample was designated D2. SEM showed uneven graphene coverage on its surface, with numerous exposed areas.

[0039] Comparative Example 3 Using the same titanium plate as in Example 1, high-temperature activation and in-situ synchronous CVD growth were performed directly without pretreatment. The difference from Example 1 was that no substrate pretreatment was performed; all other steps were exactly the same. A Ti / TiC / graphene composite film was obtained, and the resulting sample was designated D3. Figure 3 The surface morphology before and after coating is shown. The substrate surface is relatively flat before coating, and the resulting film is also relatively flat.

[0040] Comparative Example 4 The same titanium plate as in Example 1 was used, but without any pretreatment, it was directly activated at high temperature (the same as the high temperature activation in Example 1). The coating was grown in situ by synchronous CVD (different from Example 1): the temperature was maintained at 850°C, and methane (CH4) was introduced into the quartz tube furnace as a carbon source at a flow rate of 30 sccm while maintaining the total flow rate of the argon-hydrogen mixture. The deposition reaction lasted for 50 minutes. The methane was not introduced alternately. During this process, the carbon atoms generated by the cracking of methane directly grew a single-layer graphene active layer with the same thickness as sample D3 on the titanium plate, without forming a titanium carbide transition layer. The resulting sample was designated as D4.

[0041] 1. Adhesion test: The adhesion of samples S1, D1, and D2 was tested using the cross-cut adhesion test (ASTM D3359). Results: The edges of the scratches on S1 were smooth with no coating peeling, resulting in an adhesion grade of 5B. On D1, the coating almost completely peeled off in the cross-cut area, resulting in an adhesion grade of 0B. On D2, some areas of the coating peeled off or detached from the substrate during the cross-cut test, resulting in an adhesion grade of 1B-2B. These results directly demonstrate that the coating obtained by the method of this invention possesses superior interfacial bonding strength.

[0042] 2. Thin film lifetime test: ① Testing machine: Pin-disc friction and wear testing machine; grinding material: GCr15 steel ball (φ6mm); load: 5N; rotation speed: 200rpm; wear radius: 3mm; testing environment: room temperature, relative humidity: 50%. The above experimental conditions were used to test sample S1 of Example 1 and sample D3 of Comparative Example 3. The coating of sample S1 completely detached after more than 40,000 hours, while the coating of sample D3 completely detached after 4,000 hours. The lifespan of sample S1 was more than three times longer than that of D3, indicating that substrate pretreatment can increase the lifespan of the film.

[0043] ② Saltwater electrolysis experiment in acidic + alkaline environments: Electrode: Samples D3 and D4 are used as anodes, and platinum sheets are used as cathodes.

[0044] Simulated electrolytes: acidic environment brine electrolyte: sodium chloride solution with added hydrochloric acid, molar concentration of 3%, and alkaline environment brine electrolyte: sodium chloride solution with added sodium hydroxide, molar concentration of 3%.

[0045] Reaction conditions: Electrode spacing 2 cm, constant current density 20 mA / cm² 2 Magnetic stirring, reaction at room temperature.

[0046] Experimental results: The service life of sample D3 is less than 10,000 hours, while the service life of sample D4 is greater than 30,000 hours.

[0047] The lifetime of sample D3 in the same electrolyte was more than three times that of sample D4, indicating that the multi-layer interface with a transition layer in the coating can increase the lifetime of the coating.

[0048] By comparing sample S1 with sample D3 and sample D3 with sample D4, it is demonstrated that the preparation method of this application can increase the service life of the coating.

[0049] 3. Experiment on electrochemical oxidation degradation of antibiotic wastewater: Electrodes: Samples S1, S2, S3, D1 and a commercial ruthenium-iridium coated titanium electrode (DSA) were used as anodes, and platinum sheets were used as cathodes.

[0050] Simulated wastewater: A mixed organic wastewater containing tetracycline hydrochloride (20 mg / L), sulfamethoxazole (20 mg / L) and ibuprofen (20 mg / L) was prepared, with 0.1 M Na2SO4 as the supporting electrolyte, initial pH≈6.5, and a total volume of 200 mL.

[0051] Reaction conditions: Electrode spacing 2 cm, constant current density 20 mA / cm² 2 Magnetic stirring, reaction at room temperature.

[0052] Detection method: Samples were taken at regular intervals, filtered through a 0.22 μm filter membrane, and the residual concentration of each pollutant was determined by high performance liquid chromatography (HPLC).

[0053] Degradation Results: As shown in Table 1, after 120 minutes of reaction, the removal rates of the three typical pollutants using the electrode prepared with sample S1 all exceeded 58%. In comparison, under the same conditions, the removal rate of the three typical pollutants using electrode D1 was only 28% at most within 120 minutes, while the commercial ruthenium-iridium coated titanium electrode (DSA) achieved a total removal rate of 55% at most within 120 minutes. This indicates that the removal rates of the three typical pollutants using the electrode prepared with sample S1 after 120 minutes of reaction were higher than those using electrode D1 and the commercial ruthenium-iridium coated titanium electrode (DSA).

[0054] Compared to electrode S1, the removal rates of three typical pollutants at electrode S2 (20 minutes) and electrode S3 (30 minutes) showed that the removal rates of tetracycline hydrochloride and sulfamethoxazole gradually increased from electrode S1 to S3. The removal rates of ibuprofen were similar between electrodes S1 and S2, while the removal rate at electrode S3 was higher than that at both S1 and S3. This indicates that increasing the thickness of the TiC transition layer and the number of graphene layers can increase the removal rate of pollutants.

[0055] The comparison between electrodes S1, S2, and S3 and electrodes DSA and D1 is shown in Table 1: 4. Stability Test: The S1 electrode was run continuously for 10 cycles (60 minutes per cycle) under the same conditions, with fresh simulated wastewater replaced after each cycle. After 10 cycles, its average removal rate of mixed pollutants remained above 92%, and there were no macroscopic changes on the electrode surface. No titanium ion dissolution was detected in the solution, demonstrating its excellent long-term operational stability.

[0056] The above experimental data demonstrate that this invention prepares Ti / TiC / graphene electrode materials by chemical etching, shot blasting, high-temperature reduction activation, and CVD growth on a titanium substrate. This process maintains a high removal rate of organic wastewater while extending the material's lifespan.

[0057] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing an electrode material for electrochemical oxidation treatment of organic wastewater, wherein the organic wastewater contains a high concentration of salt, characterized in that... The electrode material comprises, in sequence, a titanium substrate, a titanium carbide transition layer, and a graphene active layer, which are laminated in layers. The titanium carbide transition layer is a dense layer formed by the diffusion reaction of carbon atoms into the interior of the titanium substrate. The graphene active layer is a single layer or multiple layers of graphene, and the microstructure of the graphene active layer is wrinkled. The electrode material is prepared by the following method: S1: Pretreatment of the titanium substrate: chemical etching and shot blasting, wherein the shot blasting is specifically performed by using G80 cast steel sand to blast the surface of the etched titanium substrate. S2: High-temperature reduction activation treatment of the pretreated titanium substrate: The pretreated titanium substrate is placed in a vacuum furnace and heated to 800-1200℃ at a rate of 5-20℃ / min under an inert protective atmosphere; then a reducing gas is introduced to reduce and activate the surface of the titanium substrate for 10-60min. S3: Using vapor deposition technology, carbon source gas is introduced into a vacuum furnace to generate a titanium carbide transition layer and a graphene active layer in situ.

2. The method for preparing electrode materials for electrochemical oxidation treatment of organic wastewater according to claim 1, characterized in that, The chemical etching in step S1 involves mechanically polishing the titanium substrate, followed by chemical etching in an acidic etching solution to completely remove the surface oxide layer and obtain a micro-rough structure. The substrate is then cleaned, dried, and ready for use.

3. The method for preparing electrode materials for electrochemical oxidation treatment of organic wastewater according to claim 2, characterized in that, The acid etching solution is a mixed aqueous solution of hydrofluoric acid and nitric acid, wherein the volume fraction of hydrofluoric acid is 1-10%, the volume fraction of nitric acid is 5-30%, the etching time is 3-30 minutes, and the etching temperature is 20-60℃.

4. The method for preparing electrode materials for electrochemical oxidation treatment of organic wastewater according to claim 1, characterized in that, The reducing gas is hydrogen or a mixture of hydrogen and an inert gas.

5. The method for preparing electrode materials for electrochemical oxidation treatment of organic wastewater according to claim 1, characterized in that, In step S3: the flow rate of the carbon source gas is 10-100 mL / min, the carbon source gas is alternately introduced, the deposition temperature is 800-1200℃, and a titanium carbide transition layer and a graphene active layer are generated in situ on the titanium substrate.

6. The method for preparing electrode materials for electrochemical oxidation treatment of organic wastewater according to claim 1 or 5, characterized in that, The carbon source gas is one or more of methane, ethylene, or acetylene.

7. The method for preparing electrode materials for electrochemical oxidation treatment of organic wastewater according to claim 1, characterized in that, The thickness of the titanium carbide transition layer is 50-500 nm.

8. An electrode material for electrochemical oxidation treatment of organic wastewater as described in any one of claims 1-7, characterized in that, The electrode material comprises, in sequence, a titanium substrate, a titanium carbide transition layer, and a graphene active layer, which are laminated in layers. The titanium carbide transition layer is a dense layer formed by the diffusion reaction of carbon atoms into the titanium substrate. The graphene active layer is a single layer or multiple layers of graphene, and the microstructure of the graphene active layer is wrinkled.

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