Magnetite-polypyrrole composite conductive magnetic electrode, preparation method and application thereof, and method for treating petrochemical wastewater

Abstract

The invention relates to the technical field of sewage treatment, and provides a magnetite-polypyrrole composite conductive magnetic electrode, a preparation method and application thereof, and a method for treating petrochemical wastewater. The composite conductive magnetic electrode provided by the invention comprises an electrode and a modification layer coating the surface of the electrode, wherein the modification layer comprises magnetite and polypyrrole. The composite conductive magnetic electrode provided by the invention has excellent conductivity and magnetism and relatively high stability, can give full play to the synergistic effect of a magnetic material and a conductive material, improves the efficiency of electrochemical reaction, and remarkably enhances the removal effect of organic pollutants in petrochemical wastewater. By adopting the electrode disclosed by the invention, efficient, green and low-energy-consumption treatment of petrochemical wastewater can be realized, and the electrode has a wide application prospect in the fields of environmental protection and industrial wastewater treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a magnetite-polypyrrole composite conductive magnetic electrode, a preparation method and application thereof, and a method for treating petrochemical wastewater. Background Art

[0002] With the rapid development of the global economy and the advancement of industrialization and urbanization, wastewater treatment has become a critical component of environmental protection and sustainable resource utilization. In the petrochemical industry, in particular, wastewater often contains a large amount of harmful substances, such as petroleum pollutants, heavy metal ions, and other organic pollutants. The discharge of these pollutants not only poses a serious threat to the environment, but also affects human health and the balance of ecosystems. Therefore, the development of efficient, green, and low-cost petrochemical wastewater treatment technologies is particularly important.

[0003] Traditional sewage treatment methods include physical, chemical and biological methods. Although these methods can remove pollutants in water to a certain extent, they still have problems such as low efficiency, high energy consumption, high operating costs, and secondary pollution. New technologies and materials are urgently needed.

[0004] In recent years, electrochemical water treatment technologies have garnered widespread attention due to their high efficiency, energy conservation, and environmental friendliness. Electrochemical treatment of petrochemical wastewater involves purifying wastewater by applying electricity to electrode materials in an electrolytic cell to generate an electrochemical reaction. Electrode materials play a key role in this process. However, existing electrode materials are mostly single materials with limited conductivity and stability, resulting in low reaction efficiency and contaminant removal rates during electrochemical treatment. Summary of the Invention

[0005] In light of this, the present invention provides a magnetite-polypyrrole composite conductive magnetic electrode, its preparation method, its application, and a method for treating petrochemical wastewater. The composite conductive magnetic electrode provided by the present invention combines excellent conductivity and magnetism with high stability, achieving high reaction efficiency and pollutant removal rates in electrochemical wastewater treatment.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A magnetite-polypyrrole composite conductive magnetic electrode comprises an electrode and a modified layer coated on the surface of the electrode; the modified layer comprises magnetite and polypyrrole.

[0008] Preferably, the electrode is a graphite electrode.

[0009] The present invention also provides a method for preparing the magnetite-polypyrrole composite conductive magnetic electrode described in the above scheme, comprising the following steps:

[0010] The electrode is immersed in a polyvinyl pyrrolidone-ferric chloride mixed solution and then dried and pyrolyzed to obtain a magnetite-modified electrode;

[0011] The magnetite modified electrode is immersed in a pyrrole-chitosan mixed solution for electrochemical deposition to obtain the magnetite-polypyrrole composite conductive magnetic electrode.

[0012] Preferably, the concentration of polyvinyl pyrrolidone in the polyvinyl pyrrolidone-ferric chloride mixed solution is 15-25 g / L, and the concentration of ferric chloride is 10-20 g / L; and the immersion time is 6-10 hours.

[0013] Preferably, the pyrolysis temperature is 450-550° C., the time is 3-6 hours, and the heating rate to the pyrolysis temperature is 3-8° C. / min.

[0014] Preferably, the pyrrole-chitosan mixed solution is obtained by mixing chitosan solution and pyrrole; the solvent of the chitosan solution is acetic acid solution; the concentration of chitosan in the chitosan solution is 4-6 g / L; the content of pyrrole in the polypyrrole-chitosan mixed solution is 7-9 mL / L.

[0015] Preferably, the electrochemical deposition conditions include: a current density of 3 to 7 mA / cm 2 , the sedimentation time is 18 to 22 minutes.

[0016] The present invention also provides the use of the magnetite-polypyrrole composite conductive magnetic electrode described in the above scheme or the magnetite-polypyrrole composite conductive magnetic electrode prepared by the preparation method described in the above scheme in treating wastewater.

[0017] The present invention also provides a method for treating petrochemical wastewater, comprising the following steps:

[0018] In an external magnetic field, a two-electrode system is used to degrade petrochemical wastewater, wherein the electrodes in the two-electrode system include a modified electrode and a counter electrode; the modified electrode is the magnetite-polypyrrole composite conductive magnetic electrode described in the above scheme or the magnetite-polypyrrole composite conductive magnetic electrode prepared by the preparation method described in the above scheme.

[0019] Preferably, during the degradation process, the voltage of the two-electrode system is 1.0 to 1.5 V;

[0020] The magnetic field strength of the external magnetic field is 40 to 60 mT;

[0021] The external magnetic field is applied by placing rubidium magnets on both sides and the bottom of the two-electrode system, and controlling the magnetic field intensity by changing the distance between the rubidium magnets and the two-electrode system.

[0022] The present invention provides a magnetite-polypyrrole composite conductive magnetic electrode, comprising an electrode and a modified layer coated on the surface of the electrode; the modified layer comprises magnetite and polypyrrole. The present invention modifies the surface of the electrode material with magnetite and polypyrrole. Magnetite, as a conductive and magnetic material, can effectively enhance the electron transfer ability of the electrode and improve the electrochemical reaction activity of the electrode. In addition, the magnetic characteristics of magnetite and the application of magnetic fields can also enhance the interaction between the electrode and pollutants in sewage, further improving the treatment effect; and the magnetic responsiveness of magnetite facilitates positioning and removal through the magnetic field, realizing the detachable operation and recycling of the electrode, reducing operating costs and extending service life. Polypyrrole, as a conductive polymer, has excellent electrical conductivity and stability, which can further promote the electron transfer efficiency on the electrode surface. The composite conductive magnetic electrode provided by the present invention combines the excellent properties of magnetic materials and conductive materials, fully utilizes the synergistic effect of magnetic materials and conductive materials, and has strong stability and recyclability. It can effectively adsorb and catalytically degrade organic pollutants in petrochemical wastewater. Compared with traditional electrode materials, the composite conductive magnetic electrode of the present invention has higher electrochemical reaction efficiency, can significantly enhance the removal efficiency of organic pollutants in petrochemical wastewater, and shorten the treatment time.

[0023] At the same time, the composite conductive magnetic electrode provided by the present invention also has high chemical stability and mechanical strength, can maintain high treatment efficiency and good structural integrity during long-term operation, and extend the service life of the electrode. This stability enables the electrode of the present invention to continue to operate efficiently in petrochemical wastewater treatment environments with different TPH concentrations, reducing the frequency of equipment maintenance and replacement. The composite conductive magnetic electrode of the present invention is applied to the treatment of petrochemical wastewater, which can effectively reduce energy consumption in wastewater treatment, reduce environmental pollution, and achieve efficient removal of pollutants in wastewater. It has the advantage of being green and environmentally friendly, and has broad application prospects in the fields of environmental protection and industrial wastewater treatment.

[0024] The present invention also provides a method for preparing the magnetite-polypyrrole composite conductive magnetic electrode described in the above scheme. The present invention utilizes a two-step method for composite modification of magnetite and polypyrrole materials. Magnetite is first modified on the electrode material surface by an impregnation-pyrolysis method, and then the polypyrrole is modified by electrochemical deposition. The preparation method provided by the present invention is simple to operate and easy to implement.

[0025] The present invention also provides a method for treating petrochemical wastewater, comprising the following steps: in an external magnetic field, using a two-electrode system to degrade the petrochemical wastewater, the electrodes in the two-electrode system comprising a modified electrode and a counter electrode; the modified electrode is the magnetite-polypyrrole composite conductive magnetic electrode described in the above scheme. The present invention can effectively improve the efficiency of pollutant removal by combining magnetism with conductivity. By applying an external magnetic field, it can further promote the migration of pollutants on the electrode surface and the transfer of electrons, optimize the electrochemical reaction process, accelerate the reaction rate, promote the degradation of pollutants, and reduce energy consumption during the treatment process. In addition, the method provided by the present invention is also characterized by simple operation and easy maintenance. The electrode surface is not easily completely blocked by pollutants, cleaning and maintenance work are relatively simple, and the cost of using and replacing the equipment is low. In addition, the method provided by the present invention also has a high degree of system integration and can adapt to the sewage treatment needs of different scales and working conditions. It is not only suitable for the treatment of petrochemical wastewater, but also can be adjusted and optimized according to the properties of the wastewater. For example, the enrichment of pollutants can be controlled by adjusting the external magnetic field strength (40 to 60 mT); the electron transfer rate and reaction rate can be adjusted by adjusting the external voltage; and the composite electrode of the present invention has a flexible structure, and the size, number and arrangement of the electrodes can be selected according to the concentration of organic matter in the wastewater; through the above-mentioned adjustment, it can adapt to the treatment needs of various types and pollutant concentrations of wastewater, and has broad application prospects.

[0026] In summary, the method provided by the present invention not only significantly improves the treatment efficiency of petrochemical wastewater, but also reduces energy consumption and improves system stability, providing an important reference for the optimization and application of electrochemical water treatment technology. At the same time, on the basis of achieving efficient treatment, the present invention promotes the development of wastewater treatment technology in the direction of low carbon and stability, and opens up a new path for improving the green, efficient, sustainable level and application prospects of petrochemical wastewater treatment. It has significant innovation and practical application value in the field of petrochemical wastewater treatment technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the preparation of magnetite-polypyrrole composite conductive magnetic electrode and treatment of petrochemical wastewater according to the present invention;

[0028] Figure 2 The curve of total petroleum hydrocarbon content in petrochemical wastewater at different time points;

[0029] Figure 3 The changes in the removal rate of total petroleum hydrocarbons in petrochemical wastewater at different time points. DETAILED DESCRIPTION

[0030] The invention provides a magnetite-polypyrrole composite conductive magnetic electrode, comprising an electrode and a modification layer coated on the surface of the electrode; the modification layer comprises magnetite and polypyrrole.

[0031] In the present invention, the magnetite is specifically nanomagnetite; the electrode is preferably a graphite electrode; specifically a graphite electrode sheet.

[0032] In the present invention, the modified layer specifically includes a magnetite layer modified on the surface of the electrode and a polypyrrole film modified on the surface of the magnetite layer.

[0033] In the present invention, magnetite is a material with good electrical conductivity and magnetism, and polypyrrole, as a conductive polymer, has good electrical conductivity and chemical stability, and is low in cost, highly conductive in the doped state, and easy to prepare on a large scale. The present invention compounds magnetite and polypyrrole, which can give full play to the advantages of both, not only providing excellent electrical conductivity and magnetism, but also increasing the surface area of the electrode, thereby effectively improving the efficiency of the electrochemical treatment process.

[0034] The present invention also provides a method for preparing the magnetite-polypyrrole composite conductive magnetic electrode described in the above scheme, comprising the following steps:

[0035] The electrode is immersed in a polyvinyl pyrrolidone-ferric chloride mixed solution and then dried and pyrolyzed to obtain a magnetite-modified electrode;

[0036] The magnetite modified electrode is immersed in a pyrrole-chitosan mixed solution for electrochemical deposition to obtain the magnetite-polypyrrole composite conductive magnetic electrode.

[0037] The present invention involves immersing an electrode in a polyvinylpyrrolidone-ferric chloride mixed solution, followed by drying and pyrolysis, to obtain a magnetite-modified electrode. In the present invention, the electrode is preferably pretreated before immersion, preferably chemically or physically cleaned, preferably by acid cleaning, and preferably by polishing or ultrasonic cleaning. The present invention removes oxides and impurities from the electrode surface through pretreatment, thereby improving its surface affinity.

[0038] In the present invention, the concentration of polyvinyl pyrrolidone in the polyvinyl pyrrolidone-ferric chloride mixed solution is preferably 15 to 25 g / L, specifically 20 g / L, and the concentration of ferric chloride is preferably 10 to 20 g / L, specifically 15 g / L; the solvent of the polyvinyl pyrrolidone-ferric chloride mixed solution is water; the preparation method of the polyvinyl pyrrolidone-ferric chloride mixed solution preferably comprises: adding polyvinyl pyrrolidone and ferric chloride to water, stirring for 2 to 4 hours, preferably 3 hours, to obtain the polyvinyl pyrrolidone-ferric chloride mixed solution; the polyvinyl pyrrolidone is preferably PVP-K30; the ferric chloride is preferably FeCl3·6H2O, and the water is preferably deionized water.

[0039] In the present invention, the immersion time is preferably 6 to 10 hours, specifically 7 hours, 8 hours or 9 hours; the immersion is preferably carried out at room temperature; the present invention has no special requirements for the amount of the polyvinyl pyrrolidone-ferric chloride mixed solution used during the immersion, as long as it can immerse the electrode; after the immersion is completed, the electrode is preferably taken out and dried; the drying is preferably natural drying, and the drying time is preferably 12 to 24 hours.

[0040] In the present invention, the pyrolysis temperature is preferably 450-550°C, specifically 500°C; the pyrolysis time is preferably 3-6h, specifically 5h, and the heating rate to the pyrolysis temperature is preferably 3-8°C / min, specifically 5°C / min; the pyrolysis is preferably carried out in a muffle furnace.

[0041] After obtaining the magnetite modified electrode, the present invention immerses the magnetite modified electrode in a pyrrole-chitosan mixed solution for electrochemical deposition to obtain the magnetite-polypyrrole composite conductive magnetic electrode. In the present invention, the pyrrole-chitosan mixed solution is preferably obtained by mixing a chitosan solution and pyrrole; the solvent of the chitosan solution is preferably an acetic acid solution, and the concentration of the acetic acid solution is preferably 2wt%; the concentration of chitosan in the chitosan solution is preferably 4 to 6 g / L, specifically 5 g / L; the content of pyrrole in the pyrrole-chitosan mixed solution is preferably 7 to 9 mL / L, specifically 8 mL / L; in a specific embodiment of the present invention, it is preferred to first disperse chitosan in an acetic acid solution to obtain a chitosan solution, and then ultrasonically disperse pyrrole in the chitosan solution; the present invention can promote the deposition rate of pyrrole and improve the stability of the deposition process by adding chitosan.

[0042] In the present invention, the conditions for electrochemical deposition preferably include: a current density of 3 to 7 mA / cm 2 , specifically 5mA / cm 2 The deposition time is 18 to 22 minutes, specifically 20 minutes. During the electrochemical deposition process, pyrrole forms a stable polypyrrole conductive film on the surface of the magnetite modified layer, thereby obtaining a magnetite-polypyrrole composite conductive magnetic electrode.

[0043] The present invention also provides the use of the magnetite-polypyrrole composite conductive magnetic electrode described in the above scheme, or the magnetite-polypyrrole composite conductive magnetic electrode prepared by the preparation method described in the above scheme, in treating wastewater; the wastewater is preferably petrochemical wastewater. In the present invention, the magnetite-polypyrrole composite conductive magnetic electrode has excellent stability and conductivity, enabling the system to maintain high treatment efficiency during long-term operation while reducing energy consumption. The use of magnetic materials also makes pollutant recovery more efficient, reducing secondary pollution and waste generation. By combining magnetic and conductive properties, the present invention can effectively improve pollutant removal efficiency.

[0044] The present invention also provides a method for treating petrochemical wastewater, comprising the following steps:

[0045] In an external magnetic field, a two-electrode system is used to degrade petrochemical wastewater, wherein the electrodes in the two-electrode system include a modified electrode and a counter electrode; the modified electrode is the magnetite-polypyrrole composite conductive magnetic electrode described in the above scheme or the magnetite-polypyrrole composite conductive magnetic electrode prepared by the preparation method described in the above scheme.

[0046] In the present invention, the content of petroleum hydrocarbons (TPH) in the petrochemical wastewater is preferably 50 to 300 mg / L, preferably 80 to 150 mg / L.

[0047] In the present invention, the counter electrode is preferably an unmodified electrode, specifically an unmodified graphite electrode.

[0048] In the present invention, during the degradation process, the voltage of the two-electrode system is preferably 1.0-1.5V, specifically 1.2V.

[0049] In the present invention, the magnetic field strength of the external magnetic field is preferably 40 to 60 mT, specifically 50 mT. The method for applying the external magnetic field is preferably to place rubidium magnets on both sides and at the bottom of the two-electrode system, and to control the magnetic field strength by varying the distance between the rubidium magnets and the two-electrode system. In the present invention, applying an external magnetic field not only enhances the magnetite's ability to adsorb pollutants but also accelerates the migration of pollutants across the electrode surface through the guiding effect of the magnetic field, thereby optimizing the electrochemical degradation process. During the electrochemical reaction, the external magnetic field can enhance the conductivity of the electrodes, promote electron transfer, and increase the reaction rate and efficiency. Furthermore, the magnetic field can induce localized changes in current distribution on the electrode surface, thereby improving pollutant removal. When treating petrochemical wastewater containing organic pollutants and heavy metal ions, applying an external magnetic field can not only increase pollutant removal rates but also effectively reduce secondary pollution, further enhancing the green and economical nature of wastewater treatment.

[0050] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] Example 1

[0052] according to Figure 1 The magnetite-polypyrrole composite conductive magnetic electrode is prepared by the process in the present invention, and the magnetite-polypyrrole composite conductive magnetic electrode is used to treat petrochemical wastewater. The specific steps are as follows:

[0053] 1) Preparation of magnetite-polypyrrole composite conductive magnetic electrode

[0054] Preparation of magnetite-modified graphite sheet electrode: PVP K30 and FeCl3·6H2O were dissolved in deionized water to prepare a solution with a PVP K30 concentration of 20 g / L and a FeCl3·6H2O concentration of 15 g / L. The solution was stirred for 3 hours until the solution was uniform. A graphite sheet electrode (length 6.0 cm, width 1.0 cm, effective reaction area of about 4.5 cm) was prepared. 2 ) was immersed in the prepared solution for 8 hours to allow the solution to fully penetrate the graphite sheet surface. The electrode was then removed and dried at room temperature overnight. The graphite sheet electrode was then placed in a muffle furnace and heated at 5°C / min to 500°C for 5 hours. This heat formed a magnetite-modified layer, resulting in a magnetite-modified graphite sheet electrode.

[0055] Preparation of magnetite-polypyrrole composite conductive magnetic electrode: Chitosan (5 g / L) was dispersed in an acetic acid solution, and pyrrole (8 mL / L) was ultrasonically dispersed into the above solution. After mixing, an electrochemical deposition solution containing polypyrrole was prepared. The magnetite-modified graphite sheet electrode was immersed in the above electrochemical deposition solution and electrochemical deposition was carried out by applying power. The current density of the electrochemical deposition was 5 mA / cm 2 During the electrochemical reaction, polypyrrole forms a stable conductive film on the surface of the magnetite modified layer, obtaining a magnetite-polypyrrole composite conductive magnetic electrode.

[0056] 2) Methods of petrochemical wastewater treatment

[0057] The total petroleum hydrocarbon content in the petrochemical wastewater to be treated is 100 mg / L.

[0058] The magnetite-polypyrrole composite conductive magnetic electrode and the unmodified graphite sheet electrode were used as the two electrodes of the reactor, respectively, to form a two-electrode system. The reactor was placed in an artificial external magnetic field for wastewater treatment. During the treatment process, an external voltage of 1.2V was applied to promote the degradation of harmful substances in petrochemical wastewater through electrochemical reactions. To enhance the reaction efficiency of the electrodes, rubidium magnets were placed on both sides and at the bottom of the reactor to generate a static magnetic field. By adjusting the distance between the magnet and the electrode system, the magnetic field strength was controlled to 50mT. This treatment group was labeled PF.

[0059] During the operation of the reactor, the treated petrochemical wastewater was sampled and tested at different time points. The samples were centrifuged for 5 minutes at a speed of 12,000 rpm. The supernatant was filtered through a 0.45 μm filter membrane to remove impurities. After extraction, the samples were tested using gas chromatography, and the concentration of petroleum hydrocarbons in the treated petrochemical wastewater was calculated.

[0060] Comparative Example 1

[0061] Refer to the process of Example 1, the only difference is that the electrode is not modified with polypyrrole; the unmodified polypyrrole electrode (i.e., magnetite-modified graphite sheet electrode) is used to treat petrochemical wastewater, and the treatment conditions are the same as in Example 1. This treatment group is marked as PO.

[0062] Comparative Example 2

[0063] Refer to the process of Example 1, the only difference is that the electrode is not modified with magnetite; the electrode without modified magnetite (i.e., polypyrrole-modified graphite sheet electrode) is used to treat petrochemical wastewater, and the treatment conditions are the same as in Example 1. This treatment group is marked as FO.

[0064] Comparative Example 3

[0065] Referring to the process of Example 1, the only difference is that the electrode material is not modified; the petrochemical wastewater is treated with an unmodified graphite sheet electrode, and the treatment conditions are the same as in Example 1. This treatment group is marked as Con.

[0066] Test Case

[0067] Figure 2 The curves of the total petroleum hydrocarbon content in petrochemical wastewater at different time points are shown in Figure 1, where PF, PO, FO, and Con represent the treatment methods of different experimental groups: PF is Example 1 (magnetite-polypyrrole composite conductive magnetic electrode group), PO is Comparative Example 1 (only magnetite modified electrode group), FO is Comparative Example 2 (only polypyrrole modified electrode group), and Con is Comparative Example 3 (unmodified electrode group). Figure 2It can be seen that the rate of decrease of TPH concentration in Example 1 (PF group) during the treatment process is significantly faster than that of the other control groups. The TPH concentration of the PF group decreased most significantly, decreasing to about 40 mg / L after 20 h, and after 40 h, the TPH concentration had dropped to below 20 mg / L, indicating that the composite conductive magnetic electrode of the present invention has significant advantages in removing petroleum hydrocarbons. The rate of decrease of TPH concentration in the PO group and the FO group was slightly lower than that in the PF group, and after 40 h, the TPH concentration remained at about 30 mg / L and 40 mg / L, respectively. The degradation effect of the Con group was the worst, and the TPH concentration was still close to 60 mg / L at 40 h, indicating that the treatment effect of the traditional graphite electrode was limited.

[0068] Figure 3 The changes in the removal rate of total petroleum hydrocarbons in petrochemical wastewater at different time points. Figure 3 It can be seen that the total petroleum hydrocarbon removal rate after treatment gradually increases with time, among which the removal rate of Example 1 has exceeded 60% in the 6th hour. After 30 hours of treatment, the total petroleum hydrocarbon removal rate of Example 1 (PF group) reached 92%, while that of Comparative Example 1 (PO group) and Comparative Example 2 (FO group) was 80% and 75%, respectively. The removal rate of the unmodified graphite electrode group (Con group) was the lowest, indicating that the treatment effect of relying solely on traditional electrode materials is relatively limited. The total petroleum hydrocarbon removal rate of Example 1 was significantly higher than that of the other groups, indicating that the magnetite-polypyrrole composite conductive magnetic electrode can significantly improve the treatment effect. Figure 3 The data also show that the removal efficiency of the PF group is better than that of the control group throughout the treatment process, especially in the early stage (6h to 24h), which shows a faster removal rate. As the treatment time increases, the advantage of the PF group is more obvious, indicating the efficiency and stability of the magnetite-polypyrrole composite conductive magnetic electrode in treating petrochemical wastewater. It can be inferred from these data that the magnetite-polypyrrole composite conductive magnetic electrode effectively promotes the enrichment of microorganisms and the acceleration of electrochemical reactions by improving the conductivity and magnetism of the electrode, thereby significantly improving the removal efficiency of petroleum hydrocarbons in petrochemical wastewater. The electrode in Example 1 performs well in petrochemical wastewater treatment and provides an efficient and green treatment solution.

[0069] In addition, the electrode prepared in Example 1 was used to treat petrochemical wastewater with a TPH concentration of 50 mg / L. The treatment conditions were the same as in Step 2 of Example 1. Testing was performed after 40 hours of treatment. The results showed that the TPH concentration in the petrochemical wastewater was reduced to 4 mg / L, and the TPH removal rate was 92%.

[0070] The electrode prepared in Example 1 was used to treat petrochemical wastewater with a TPH concentration of 300 mg / L, using the same treatment conditions as in step 2 of Example 1. Testing after 40 hours of treatment revealed that the TPH concentration in the petrochemical wastewater was reduced to 32 mg / L, with a TPH removal efficiency of 89%. These results demonstrate that the composite conductive magnetic electrode of the present invention can operate efficiently in petrochemical wastewater treatment environments with varying TPH concentrations and has a wide range of applications.

[0071] The results of the above examples show that the magnetite-polypyrrole composite conductive magnetic electrode provided by the present invention has excellent conductivity, magnetism, and stability, giving full play to the synergistic effect of magnetic and conductive materials, while further optimizing the pollutant removal effect by applying an external magnetic field. The present invention not only solves the limitations of electrode materials in traditional electrochemical treatment methods, but also can achieve efficient treatment of petrochemical wastewater under green, low-energy, and high-efficiency conditions, providing an innovative solution for the field of sewage treatment, promoting the green, low-energy, and high-efficiency development of wastewater treatment technology, and improving the intelligent level of sewage treatment and system stability.

[0072] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A magnetite-polypyrrole composite conductive magnetic electrode, characterized in that: The invention comprises an electrode and a modification layer coated on the surface of the electrode; the modification layer comprises magnetite and polypyrrole.

2. The magnetite-polypyrrole composite conductive magnetic electrode according to claim 1, characterized in that: The electrode is a graphite electrode.

3. The method for preparing the magnetite-polypyrrole composite conductive magnetic electrode according to claim 1 or 2, characterized in that: The following steps are involved: The electrode is immersed in a polyvinyl pyrrolidone-ferric chloride mixed solution and then dried and pyrolyzed to obtain a magnetite-modified electrode; The magnetite modified electrode is immersed in a pyrrole-chitosan mixed solution for electrochemical deposition to obtain the magnetite-polypyrrole composite conductive magnetic electrode.

4. The preparation method according to claim 3, characterized in that The concentration of polyvinyl pyrrolidone in the polyvinyl pyrrolidone-ferric chloride mixed solution is 15-25 g / L, and the concentration of ferric chloride is 10-20 g / L; the immersion time is 6-10 hours.

5. The preparation method according to claim 3, characterized in that The pyrolysis temperature is 450-550° C., the time is 3-6 hours, and the heating rate to the pyrolysis temperature is 3-8° C. / min.

6. The preparation method according to claim 3, characterized in that The pyrrole-chitosan mixed solution is obtained by mixing chitosan solution and pyrrole; the solvent of the chitosan solution is acetic acid solution; the concentration of chitosan in the chitosan solution is 4-6 g / L; the content of pyrrole in the polypyrrole-chitosan mixed solution is 7-9 mL / L.

7. The preparation method according to claim 3, characterized in that The conditions for the electrochemical deposition include: a current density of 3 to 7 mA / cm 2 , the sedimentation time is 18 to 22 minutes.

8. Use of the magnetite-polypyrrole composite conductive magnetic electrode according to claim 1 or 2 or the magnetite-polypyrrole composite conductive magnetic electrode prepared by the preparation method according to any one of claims 3 to 7 in treating wastewater.

9. A method for treating petrochemical wastewater, characterized in that: The following steps are involved: In an external magnetic field, a two-electrode system is used to degrade petrochemical wastewater, wherein the electrodes in the two-electrode system include a modified electrode and a counter electrode; the modified electrode is the magnetite-polypyrrole composite conductive magnetic electrode described in claim 1 or 2 or the magnetite-polypyrrole composite conductive magnetic electrode prepared by the preparation method described in any one of claims 3 to 7.

10. The method according to claim 9, characterized in that During the degradation process, the voltage of the two-electrode system is 1.0 to 1.5 V; The magnetic field strength of the external magnetic field is 40 to 60 mT; The external magnetic field is applied by placing rubidium magnets on both sides and the bottom of the two-electrode system, and controlling the magnetic field intensity by changing the distance between the rubidium magnets and the two-electrode system.

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