Stainless steel carbon deposition electrode and preparation method and application thereof

Abstract

The invention provides a preparation method of a stainless steel carbon deposition electrode, which comprises the following steps: pyrolyzing a woody raw material to obtain woody biochar; preparing the woody biochar into woody biochar powder, and mixing the woody biochar powder with iron powder to obtain an iron-carbon mixture; mixing the iron-carbon mixture with a binder to obtain electrode slurry; and preparing the electrode slurry on a stainless steel mesh, and drying to obtain the stainless steel carbon deposition electrode. The invention further provides the stainless steel carbon deposition electrode and application. The stainless steel carbon deposition electrode prepared by the invention combines woody biochar, iron powder and stainless steel and has a synergistic effect, so that the degradation efficiency of the stainless steel carbon deposition electrode as a bioelectrochemical electrode on pollutants is improved.

Description

Technical Field

[0001] This invention relates to the field of bioelectrochemical technology, and in particular to a stainless steel carbon deposition electrode, its preparation method, and its application. Background Technology

[0002] A bioelectrochemical system (BES) is a device that combines biotechnology and electrochemical technology. It utilizes the metabolic activity of microorganisms and electrochemical processes to remove pollutants and recover energy. The core components of a bioelectrochemical system include an anode, a cathode, and an electrolyte solution, as well as external circuitry connecting the two electrodes.

[0003] In wastewater treatment, bioelectrochemical systems have demonstrated significant advantages. Traditional wastewater treatment methods often consume large amounts of energy and chemical reagents, while BES (bioelectrochemical electrolysis cells) can generate electricity while treating wastewater. In a typical type of bioelectrochemical system—the microbial electrolytic cell (MEC)—microorganisms decompose organic pollutants at the anode, producing electrons and protons. Electrons are transferred to the cathode through an external circuit, where they combine with oxygen and protons to form water, thus generating an electric current. This method not only reduces the chemical oxygen demand (COD) of wastewater but also generates electricity, achieving energy recovery and utilization. Due to its short treatment cycle and high efficiency, bioelectrochemical systems have become one of the alternative solutions for treating recalcitrant wastewater, and their high efficiency is reflected in the synergistic effect between the electrode microorganisms.

[0004] Electrodes are a crucial component of bioelectrochemical systems, and the configuration and performance of electrode materials determine the system's economic viability and industrialization potential. Currently, commonly used electrode materials are divided into two categories: carbon-based and metal-based. Carbon-based materials utilize one or more of carbon cloth, carbon felt, graphite, and carbon fiber brushes, while metal-based materials utilize one or more of stainless steel, titanium, nickel, and zero-valent iron. The main difference between carbon-based and metal-based materials lies in their biocompatibility and conductivity. Carbon-based materials, due to their high biocompatibility and hydrophilicity, possess advantages such as rapid biofilm formation, high pollutant mass transfer efficiency, and strong microbial adhesion ability. However, they have lower conductivity and are less economical. For example, the most common carbon fiber brush material, as a 3D structure, has a specific surface area dozens of times larger than that of 2D carbon-based materials. However, the difficulty in manufacturing carbon fiber brushes leads to higher costs, and fiber detachment can easily cause short circuits.

[0005] The biggest advantages of metal-based materials compared to carbon-based materials are their high conductivity and low hydrogen evolution potential. Currently, the most common metal-based material is stainless steel mesh, whose crisscrossing structure provides an environment for rapid biofilm formation. Researchers have already used inexpensive stainless steel as electrodes in bioelectrochemical systems to treat recalcitrant industrial wastewater from azo dye synthesis and pharmaceutical production, laying a solid foundation for the application of stainless steel in bioelectrochemical systems. However, stainless steel suffers from limited specific surface area and poor biocompatibility, which restricts its application.

[0006] Therefore, considering scalability, biocompatibility, electrochemical stability, and corrosion resistance, specific surface area and material cost are key influencing factors in the selection of electrode materials. Whether electrode materials suitable for large-scale applications can be formed based on stainless steel is a bottleneck problem in the development of bioelectrochemical technology. Summary of the Invention

[0007] The technical problem solved by this invention is to provide a method for preparing a stainless steel carbon deposition electrode, which improves the degradation efficiency of pollutants when used as a bioelectrochemical electrode.

[0008] In view of this, this application provides a method for preparing a stainless steel carbon deposition electrode, comprising the following steps:

[0009] Woody raw materials are pyrolyzed to obtain woody biochar;

[0010] The woody biochar was prepared into woody biochar powder, and then mixed with iron powder to obtain an iron-carbon mixture.

[0011] The iron-carbon mixture and binder are mixed to obtain an electrode slurry;

[0012] The electrode slurry was prepared on a stainless steel mesh and dried to obtain a stainless steel carbon deposition electrode.

[0013] In some specific embodiments, the woody raw materials include one or more of wood, fruit shells, and bamboo, and / or the pyrolysis temperature is 500–1000°C, and the specific gravity is 1.3–1.7 g / cm³. 3 .

[0014] In some specific embodiments, the method for preparing woody biochar into woody biochar powder is as follows:

[0015] Woody biochar is dried at 80-90℃ for 2-3 hours, then ground and passed through a 100-150 mesh sieve.

[0016] In some specific embodiments, the mass ratio of the woody biochar to the iron powder is (4-5):1.

[0017] In some specific embodiments, the adhesive is a mixture of polyvinylidene fluoride and N-methylpyrrolidone in a mass ratio of 1:(15-20).

[0018] In some specific embodiments, the ratio of the iron-carbon mixture to the binder is (1.5-2.0) g: 1 mL; and / or, the stainless steel mesh has a mesh size of 150-200 mesh and a thickness of 50-200 μm.

[0019] In some specific embodiments, the electrode paste is prepared on a stainless steel mesh by coating, and the coating thickness of the electrode paste is 150-200 μm.

[0020] This application also provides a stainless steel carbon deposition electrode prepared by the preparation method described above, which consists of a stainless steel mesh and a coating formed on the surface of the stainless steel mesh, wherein the coating is prepared from woody biochar and iron powder.

[0021] This application also provides a bioelectrochemical system, including a cathode, an anode, and an electrolyte solution, characterized in that the electrodes of the cathode and / or anode are stainless steel carbon deposition electrodes prepared by the preparation method described above or stainless steel carbon deposition electrodes described above.

[0022] This application also provides the application of the bioelectrochemical system described above in the degradation of pollutants.

[0023] This application provides a method for preparing a stainless steel carbon deposition electrode. First, a woody raw material is pyrolyzed. Then, the prepared woody biochar powder is mixed with iron powder to obtain an iron-carbon mixture. Next, the iron-carbon mixture is mixed with a binder to obtain an electrode slurry. Finally, the electrode slurry is prepared on a stainless steel mesh and dried to obtain the stainless steel carbon deposition electrode. In the preparation process of the stainless steel carbon deposition electrode, the mixing of woody biochar powder and iron powder improves the electrode's conductivity. Simultaneously, the conductivity of the stainless steel mesh and the high specific surface area of ​​the woody biochar promote microbial growth and electron transfer. Therefore, the prepared stainless steel carbon deposition electrode, as a bioelectrochemical electrode, improves the degradation efficiency of pollutants. Attached Figure Description

[0024] Figure 1 This is a horizontal bar chart showing the microbial community in leachate from different stainless steel electrodes. Detailed Implementation

[0025] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0026] Given the performance requirements of electrodes for bioelectrochemical pollutant degradation, this application provides a stainless steel carbon deposition electrode and its preparation method. This stainless steel carbon deposition electrode combines woody biochar, iron powder, and stainless steel, with synergistic effects to improve its efficiency in pollutant degradation as a bioelectrochemical electrode. Specifically, this invention discloses a method for preparing a stainless steel carbon deposition electrode, including the following steps:

[0027] Woody raw materials are pyrolyzed to obtain woody biochar;

[0028] The woody biochar was prepared into woody biochar powder, and then mixed with iron powder to obtain an iron-carbon mixture.

[0029] The iron-carbon mixture and binder are mixed to obtain an electrode slurry;

[0030] The electrode slurry was prepared on a stainless steel mesh and dried to obtain a stainless steel carbon deposition electrode.

[0031] In the preparation method of stainless steel carbon deposition electrode, this application first pyrolyzes woody raw materials to obtain woody biochar. During this process, the woody raw materials are those well-known to those skilled in the art. For example, the woody raw materials include one or more of wood, fruit shells, and bamboo. Specifically, the woody raw materials are selected from wood, fruit shells, or bamboo. In a specific embodiment, the woody raw materials are selected from coconut shells or bamboo. The pyrolysis causes the woody raw materials to form woody biochar with a large specific surface area. The pyrolysis temperature is 500–800℃, specifically 600–750℃, and more specifically 650–700℃. The specific gravity of the pyrolyzed woody biochar is 1.3–1.7, specifically 1.4 g / cm³. 3 1.5g / cm 3 1.6g / cm 3 .

[0032] According to the present invention, the above-mentioned woody biochar is further prepared into woody biochar powder. The specific method for preparing woody biochar powder is as follows: the pyrolyzed woody biochar is dried, ground, and sieved to obtain woody biochar; the drying temperature is 80-90℃, the drying time is 2-3 hours, and the sieving is to pass through a 100-150 mesh sieve.

[0033] This application then mixes woody biochar powder and iron powder to obtain an iron-carbon mixture; the mass ratio of the woody biochar powder to the iron powder is (4-5):1. If the proportion of the woody biochar powder exceeds the above range, it will affect the catalytic effect of the stainless steel carbon deposition electrode. The iron powder is iron powder well known to those skilled in the art, and this application does not impose any special restrictions on its source.

[0034] After obtaining the iron-carbon mixture, it is mixed with a binder to obtain an electrode slurry. In this process, the binder is a mixture of polyvinylidene fluoride (PVDF) and N-methylpyrrolidone (N-Methylpyrrolidone) in a mass ratio of 1:(15-20). This binder ratio helps ensure the fluidity, stability, and coating performance of the electrode slurry. A ratio outside this range may result in excessively high or low viscosity of the electrode slurry, affecting the subsequent coating effect and uniformity. Specifically, the mass ratio of PVDF to N-Methylpyrrolidone is 1:(16-18). The ratio of the iron-carbon mixture to the binder is (1.5-2.0) g:1 mL, specifically (1.6-1.8) g:1 mL.

[0035] According to the present invention, the electrode paste is finally prepared on a stainless steel mesh and dried to obtain a stainless steel carbon deposition electrode. In the above process, the method of preparing the electrode paste on the stainless steel mesh is specifically as follows: the electrode paste is coated on the stainless steel mesh; the coating thickness of the electrode paste is 150-200 μm, specifically, the coating thickness of the electrode paste is 160-180 μm; the electrode paste is coated on the stainless steel mesh in a way that prevents the electrode paste from passing through the stainless steel mesh, and is coated on the surface of the stainless steel mesh.

[0036] In this application, the stainless steel mesh is a stainless steel mesh with uniformly distributed pores. Specifically, the pore size of the stainless steel mesh is 150-200 mesh, more specifically, 160-180 mesh. The thickness of the stainless steel mesh is 50-200 μm, specifically, 100-150 μm. Stainless steel mesh with the above-mentioned pore size range can provide a high specific surface area, which is beneficial for microbial attachment and biofilm formation. If the pores are too large, the current density may decrease due to insufficient surface active area. Stainless steel mesh with the above-mentioned thickness range can reduce electron transport paths and internal resistance, thereby increasing local current density.

[0037] The drying temperature is 60-65℃, and the time is 2-3 hours.

[0038] This application also provides a stainless steel carbon deposition electrode prepared by the above preparation method, which consists of a stainless steel mesh and a coating formed on the surface of the stainless steel mesh, the coating being prepared from woody biochar and iron powder.

[0039] In the stainless steel carbon deposition electrode, the stainless steel mesh is a uniformly distributed pore size, specifically, the pore size of the stainless steel mesh is 150-200 mesh, more specifically, the pore size of the stainless steel mesh is 160-180 mesh. The thickness of the stainless steel mesh is 50-200 μm, specifically, the thickness of the stainless steel mesh is 100-150 μm. The thickness of the coating is 100-200 μm, specifically, the thickness of the coating is 120-150 μm.

[0040] This application also provides a bioelectrochemical system, including a cathode, an anode, and an electrolyte solution, wherein the cathode and / or anode electrodes are stainless steel carbon deposition electrodes as described above; the electrolyte solution is a conventional electrolyte solution for those skilled in the art, and this application does not impose any special limitations on it.

[0041] This application also provides the application of the above-mentioned bioelectrochemical system in pollutant degradation; in a specific embodiment, the bioelectrochemical system is used to degrade landfill leachate.

[0042] This application provides a stainless steel carbon deposition electrode and its preparation method. The electrode uses woody raw materials such as wood, fruit shells or bamboo to prepare biochar, which implements the concept of treating waste with waste and provides a new approach for industrial production. The woody biochar is combined with iron to form an iron-carbon mixture, which improves the conductivity of the electrode. At the same time, the conductivity of the stainless steel mesh and the high specific surface area of ​​the woody biochar work together to promote the growth of microorganisms and electron transfer, thereby improving the degradation efficiency of pollutants by the bioelectrochemical system.

[0043] To further understand the present invention, the stainless steel carbon deposition electrode, its preparation method and its application are described in detail below with reference to the embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0044] Example 1

[0045] Coconut shells were pyrolyzed at 600℃ to obtain woody biochar with a specific gravity of 1.5 g / cm³. 3 Then, dry it at 85℃ for 2 hours, grind it through a 100-mesh sieve, and obtain woody biochar powder;

[0046] Woody biochar powder and iron powder are mixed at a weight ratio of 5:1 to form an iron-carbon mixture. Polyvinylidene fluoride and N-methylpyrrolidone are formulated at a weight ratio of 1:20 to obtain a binder.

[0047] Add 1 ml of the above binder to 1.8 g of iron-carbon mixture to obtain electrode slurry. Coat the electrode slurry evenly on the surface of a 150-mesh stainless steel mesh with a coating thickness of 150 μm and a stainless steel mesh thickness of 100 μm.

[0048] The coated stainless steel mesh is placed in an oven and dried at 55°C for 2 hours to remove excess binder, thus obtaining a stainless steel carbon deposition electrode.

[0049] Stainless steel carbon deposition electrodes or stainless steel electrodes were used as electrodes in a bioelectrochemical system and applied to degrade landfill leachate. The specific process was as follows:

[0050] A carbon brush was used as the anode of the bioelectrochemical system, and a stainless steel mesh or the stainless steel carbon deposition electrode prepared in this embodiment was used as the cathode. Leachate from the original landfill of Qizishan Landfill in Suzhou (Suzhou, Jiangsu Province, China) was used as the electrolyte solution. The leachate was degraded using the above-mentioned bioelectrochemical system under an applied voltage of 1.2V and an external resistance of 10Ω. The stainless steel mesh had a pore size of 150 mesh and a thickness of 100μm.

[0051] The results showed that the bioelectrochemical system with stainless steel carbon deposition electrode had a maximum COD removal efficiency of 68%, while the stainless steel mesh had a maximum COD removal efficiency of 45%. Therefore, the bioelectrochemical system with stainless steel carbon deposition electrode prepared in this embodiment had a maximum COD removal efficiency that was 13% higher than that of ordinary stainless steel electrode.

[0052] This application measures the oxidation capacity of organic matter based on the change in total organic carbon (TOC) content in the degraded leachate. The TOC of the bioelectrochemical system with stainless steel mesh configuration is reduced by 56%, and the TOC of the bioelectrochemical system with stainless steel carbon deposition electrode configuration prepared in this embodiment is reduced by 64%. Therefore, the oxidation capacity of the stainless steel carbon deposition electrode prepared in this embodiment is increased by up to 8%.

[0053] Example 2

[0054] Bamboo was pyrolyzed at 650℃ to obtain woody biochar with a specific gravity of 1.6 g / cm³. 3 Then, dry at 90℃ for 2 hours, grind through a 150-mesh sieve to obtain woody biochar powder;

[0055] Woody biochar powder and iron powder are mixed at a weight ratio of 5:1 to form an iron-carbon mixture. Polyvinylidene fluoride and N-methylpyrrolidone are formulated at a weight ratio of 1:20 to obtain a binder.

[0056] Add 1 ml of the above binder to 2.0 g of iron-carbon mixture to obtain electrode slurry. Coat the electrode slurry evenly on the surface of a 200-mesh stainless steel mesh with a coating thickness of 150 μm. The thickness of the stainless steel mesh is also 150 μm.

[0057] The coated stainless steel mesh is placed in an oven and dried at 60°C for 2 hours to remove excess binder, thus obtaining a stainless steel carbon deposition electrode.

[0058] Stainless steel carbon deposition electrodes or stainless steel electrodes were used as electrodes in a bioelectrochemical system and applied to degrade landfill leachate. The specific process was as follows:

[0059] A carbon brush was used as the anode of the bioelectrochemical system, and a stainless steel mesh or the stainless steel carbon deposition electrode prepared in this embodiment was used as the cathode. Leachate from the original landfill of Qizishan Landfill in Suzhou (Suzhou, Jiangsu Province, China) was used as the electrolyte solution. The leachate was degraded using the above-mentioned bioelectrochemical system under an applied voltage of 1.2V and an external resistance of 10Ω. The stainless steel mesh had a pore size of 150 mesh and a thickness of 100μm.

[0060] The results showed that the bioelectrochemical system with stainless steel carbon deposition electrode had a maximum COD removal efficiency of 67%, while the stainless steel mesh had a maximum COD removal efficiency of 41%. Therefore, the electrochemical system with stainless steel carbon deposition electrode prepared in this embodiment had a COD removal efficiency 16% higher than that of ordinary stainless steel electrode.

[0061] This application measures the oxidation capacity of organic matter based on the change in total organic carbon (TOC) content in the degraded leachate. The TOC of the bioelectrochemical system with stainless steel mesh configuration is reduced by 54%, and the TOC of the bioelectrochemical system with stainless steel carbon deposition electrode configuration prepared in this embodiment is reduced by 65%. Therefore, the oxidation capacity of the stainless steel carbon deposition electrode prepared in this embodiment is increased by up to 11%.

[0062] Example 3

[0063] A stainless steel mesh electrode with a pore size of 150 mesh and a thickness of 100 μm and a stainless steel carbon deposition electrode prepared in Example 1 were respectively placed in the leachate of the original landfill of Qizishan Landfill in Suzhou (Suzhou, Jiangsu Province, China) for 50 days for corrosion test. The results showed that the corrosion resistance of the two electrodes was comparable.

[0064] Three different electrodes were placed in the leachate from the original landfill of Qizishan Landfill in Suzhou, Jiangsu Province, China, for microbial community analysis at the genus level. The results are as follows: Figure 1 As shown, Figure 1 The figure shows a horizontal bar chart of the microbial community of different stainless steel electrodes. In the figure, R1-2 is a stainless steel electrode with a pore size of 150 mesh and a thickness of 100 μm, R2-2 is a stainless steel carbon deposition electrode prepared by biochar and iron powder at a mass ratio of 9:1 (other preparation processes are the same as in Example 2), and R3-2 is a stainless steel carbon deposition electrode prepared in Example 2. As can be seen from the figure, the proportion of electrochemical bacteria Pseudomonas in the three electrodes is 0.61%, 0.64%, and 2.33%, respectively. Therefore, the stainless steel carbon deposition electrode prepared in Example 2 has better biocompatibility.

[0065] Cyclic voltammetry (CV) tests were performed using a CHI604E electrochemical workstation (China Instrument Co., Ltd.) to evaluate the electrochemical activity of different cathode electrodes. Specifically:

[0066] A carbon brush was used as the working electrode, a stainless steel electrode as the cathode, and a saturated calomel electrode (Model-217) as the reference electrode. CV tests were performed at a scan rate of 10 mV / s and a cycle range of +1.0 V to -1.0 V. The stainless steel electrodes included: a stainless steel electrode 1 with a pore size of 150 mesh and a thickness of 100 μm; a stainless steel carbon deposition electrode 2 made of biochar and iron powder in a mass ratio of 9:1 (other preparation processes were the same as in Example 2); and a stainless steel electrode 3 prepared in Example 2.

[0067] Experimental results show that all three stainless steel electrodes exhibit redox capabilities. Compared with stainless steel electrodes 1 and 3, stainless steel electrode 2 shows a significant oxidation response peak at -0.2V and a small reduction reaction at +0.7V in the MEC. These results indicate that stainless steel electrode 2 exposes more reaction sites after carbon deposition treatment, further improving its electrochemical reduction capability.

[0068] Comparative Example 1

[0069] Bamboo was pyrolyzed at 650℃ to obtain woody biochar with a specific gravity of 1.6 g / cm³. 3 Then, dry at 90℃ for 2 hours, grind through a 150-mesh sieve to obtain woody biochar powder;

[0070] Polyvinylidene fluoride and N-methylpyrrolidone were mixed at a weight ratio of 1:20 to obtain a binder; 1 ml of the above binder was added to 2.0 g of woody biochar powder to obtain an electrode slurry; the electrode slurry was uniformly coated on the surface of a 200-mesh stainless steel mesh with a coating thickness of 150 μm and the stainless steel mesh thickness was 150 μm.

[0071] The coated stainless steel mesh is placed in an oven and dried at 60°C for 2 hours to remove excess binder, thus obtaining a stainless steel carbon deposition electrode.

[0072] Stainless steel carbon deposition electrodes or stainless steel electrodes were used as electrodes in a bioelectrochemical system and applied to degrade landfill leachate. The specific process was as follows:

[0073] Using a carbon brush as the anode of the bioelectrochemical system and a stainless steel carbon deposition electrode prepared in this comparative example as the cathode, the leachate from the original landfill of Qizishan Landfill in Suzhou (Suzhou, Jiangsu Province, China) was used as the electrolyte solution. The leachate was degraded using the above-mentioned bioelectrochemical system under an applied voltage of 1.2V and an external resistance of 10Ω.

[0074] The results show that the bioelectrochemical system with stainless steel carbon deposition electrode configured in this comparative example has a maximum COD removal efficiency of 52%. This application measures the organic matter oxidation capacity based on the change in total organic carbon content (TOC) in the degraded leachate. The TOC of the bioelectrochemical system with stainless steel carbon deposition electrode configured in this example is reduced by 60%.

[0075] Comparative Example 2

[0076] Coconut shells were pyrolyzed at 600℃ to obtain woody biochar with a specific gravity of 1.5 g / cm³. 3 Then, dry it at 85℃ for 2 hours, grind it through a 100-mesh sieve, and obtain woody biochar powder;

[0077] Woody biochar powder and iron powder are mixed at a weight ratio of 9:1 to form an iron-carbon mixture. Polyvinylidene fluoride and N-methylpyrrolidone are formulated at a weight ratio of 1:20 to obtain a binder.

[0078] Add 1 ml of the above binder to 1.8 g of iron-carbon mixture to obtain electrode slurry. Coat the electrode slurry evenly on the surface of a 150-mesh stainless steel mesh with a coating thickness of 150 μm and a stainless steel mesh thickness of 100 μm.

[0079] The coated stainless steel mesh is placed in an oven and dried at 55°C for 2 hours to remove excess binder, thus obtaining a stainless steel carbon deposition electrode.

[0080] Stainless steel carbon deposition electrodes or stainless steel electrodes were used as electrodes in a bioelectrochemical system and applied to degrade landfill leachate. The specific process was as follows:

[0081] Using a carbon brush as the anode of the bioelectrochemical system and a stainless steel carbon deposition electrode prepared in this comparative example as the cathode, the leachate from the original landfill of Qizishan Landfill in Suzhou (Suzhou, Jiangsu Province, China) was used as the electrolyte solution. The leachate was degraded using the above-mentioned bioelectrochemical system under an applied voltage of 1.2V and an external resistance of 10Ω.

[0082] The results showed that the bioelectrochemical system with stainless steel carbon deposition electrode achieved a maximum COD removal efficiency of 59%. This application measures the organic matter oxidation capacity based on the change in total organic carbon (TOC) content in the degraded leachate. The TOC of the bioelectrochemical system with stainless steel carbon deposition electrode prepared in this comparative example was reduced by 57%.

[0083] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0084] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a stainless steel carbon deposition electrode, comprising the following steps: Woody raw materials are pyrolyzed to obtain woody biochar; The woody biochar was prepared into woody biochar powder, and then mixed with iron powder to obtain an iron-carbon mixture. The iron-carbon mixture and binder are mixed to obtain an electrode slurry; The electrode slurry was prepared on a stainless steel mesh and dried to obtain a stainless steel carbon deposition electrode.

2. The preparation method according to claim 1, characterized in that, The woody raw materials include one or more of wood, fruit shells, and bamboo, and / or the pyrolysis temperature is 500–1000℃, and the specific gravity is 1.3–1.7 g / cm³. 3 .

3. The preparation method according to claim 1, characterized in that, The specific method for preparing woody biochar into woody biochar powder is as follows: Woody biochar is dried at 80-90℃ for 2-3 hours, then ground and passed through a 100-150 mesh sieve.

4. The preparation method according to claim 1, characterized in that, The mass ratio of the woody biochar to the iron powder is (4-5):

1.

5. The preparation method according to claim 1, characterized in that, The adhesive is a mixture of polyvinylidene fluoride and N-methylpyrrolidone in a mass ratio of 1:(15-20).

6. The preparation method according to claim 5, characterized in that, The ratio of the iron-carbon mixture to the binder is (1.5-2.0) g: 1 mL; and / or, the stainless steel mesh has a mesh size of 150-200 mesh and a thickness of 50-200 μm.

7. The preparation method according to claim 6, characterized in that, The electrode paste is prepared on a stainless steel mesh by coating, and the coating thickness of the electrode paste is 150-200 μm.

8. The stainless steel carbon deposition electrode prepared by the preparation method according to any one of claims 1 to 7, comprising a stainless steel mesh and a coating formed on the surface of the stainless steel mesh, wherein the coating is prepared from woody biochar and iron powder.

9. A bioelectrochemical system comprising a cathode, an anode, and an electrolyte solution, characterized in that, The cathode and / or anode electrodes are stainless steel carbon deposition electrodes prepared by the preparation method according to any one of claims 1 to 7 or stainless steel carbon deposition electrodes according to claim 8.

10. The application of the bioelectrochemical system of claim 9 in the degradation of pollutants.

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