Microbial fuel cell cathode electrode based on sulfur autotrophic denitrification coupled electrochemical denitrification and manufacturing method thereof

Abstract

The invention discloses a preparation method of a microbial fuel cell cathode electrode based on sulfur autotrophic denitrification coupled electrochemical denitrification. The preparation method comprises the following steps: S1, preparing oyster shell powder; s2, uniformly mixing the sulfur powder, the oyster shell powder, the graphite powder and the graphite fibers according to a certain proportion; s3, carrying out a series of treatment procedures on the uniformly mixed mixture of the four raw materials to obtain a blocky microbial fuel cathode electrode material; and S4, carrying out crushing treatment on the blocky microbial fuel cathode electrode material for use. The adopted raw materials are wide in source, the preparation method is simple, the microbial fuel cell cathode electrode prepared through the method is excellent in performance, the cathode oxidation-reduction reaction can be improved, the electrochemical reversibility can be enhanced, the charge transfer impedance can be reduced, the sulfur autotrophic denitrification nitrogen removal capacity can be improved, and the microbial fuel cell cathode electrode can be applied to the field of fuel cells. The potential of improving microbial fuel cells and sulfur autotrophic denitrification is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial fuel cells, and in particular relates to a cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification and a manufacturing method thereof. Background Art

[0002] At present, the principle of sulfur autotrophic denitrification has made significant progress in the treatment of wastewater denitrification, and has the advantages of good denitrification effect and low cost; microbial fuel cells have shown good applicability to different types of organic wastewater, and corresponding research has also made significant progress. Nitrogen pollutants are important pollutants in water bodies. As an electron acceptor for sulfur autotrophic denitrification, it also has the potential to generate electricity as a fuel for microbial fuel cells, which has gradually received more attention.

[0003] Microbial fuel cells were combined with the existing denitrification and anaerobic ammonium oxidation denitrification technologies in sewage treatment plants to construct cathode denitrification microbial fuel cells and anaerobic ammonium oxidation microbial fuel cells. The performance characteristics of simultaneous denitrification and denitrification to generate electricity and simultaneous anaerobic ammonium oxidation denitrification and denitrification to generate electricity were observed, and the denitrification and electricity generation potential of the two batteries was explored. Sulfur autotrophic denitrification technology is a technology that uses the metabolic capacity of microorganisms to convert nitrate nitrogen (NO3 - -N) is reduced to nitrogen (N2). Its core is to use sulfur and its compounds as electron donors. Under anoxic or anaerobic conditions, sulfur bacteria use CO2, HCO3 - and CO3 2- Inorganic carbon such as sulfur and sulfur sulfide is used as a growth carbon source to oxidize elemental sulfur or sulfide into sulfate, and at the same time reduce nitrate ammonia to ammonia gas. This process can not only effectively remove ammonia pollutants in sewage, but also convert sulfur pollutants into harmless sulfates, thereby realizing the resource utilization of pollutants. In addition, applying an electric field to the sulfur autotrophic denitrification system can improve the electron transfer capacity and increase the nitrogen metabolic activity, thereby accelerating the nitrogen removal effect. At present, there is no report on the immobilized sulfur autotrophic bacteria cathode electrode of sulfur autotrophic denitrification coupled to microbial fuel cells in the open literature. Summary of the invention

[0004] The purpose of the present invention is to provide a microbial fuel cell cathode electrode based on sulfur autotrophic denitrification coupled electrochemical denitrification and a preparation method thereof, which can participate in both sulfur autotrophic denitrification and microbial fuel cell reactions, have excellent performance, are simple and easy to use, and can participate in sulfur autotrophic denitrification and microbial fuel cell reactions. The graphite sulfur autotrophic electrode can improve cathode redox reactions, enhance electrochemical reversibility, reduce charge transfer impedance, and improve sulfur autotrophic denitrification denitrification capacity, and has the potential to improve microbial fuel cells and sulfur autotrophic denitrification.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a method for preparing a cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification, comprising the following steps: S1, preparing oyster shell powder; S2. Evenly mix sulfur powder, oyster shell powder, graphite powder and graphite fiber according to a certain proportion; S3, subjecting the uniformly mixed mixture of the above four raw materials to a series of treatment steps to obtain a block-shaped microbial fuel cathode electrode material; S4. The blocky microbial fuel cathode electrode material is crushed before use.

[0006] Furthermore, the specific process of preparing oyster shell powder in step S1 is as follows: clean the oyster shell with tap water, then clean it with ultrasonic vibration to thoroughly remove surface dirt, bake it in an oven at 80° C. for 24-32 h until it is completely dry, and crush the dried oyster shell into powder with a grinder, and pass it through a 300-mesh sieve.

[0007] Furthermore, the sulfur powder in step S2 is obtained by fully grinding the purchased sulfur powder and passing it through a 300-mesh sieve.

[0008] Furthermore, the graphite fibers in step S2 are obtained by cutting or shearing the graphite fiber strands into pieces with a length of 1-2 mm.

[0009] Furthermore, the certain proportion in step S2 refers to a weight ratio of oyster shell powder: graphite powder: graphite fiber equal to 4:2:0.4:0.05.

[0010] Furthermore, the specific process in step S3 is: putting the mixture into a 300 mL porcelain crucible, placing it in a muffle furnace at 160°C for heat treatment for 2 hours, and immediately adding a corresponding amount of sodium bicarbonate while the mixture is in a liquid state after taking it out of the muffle furnace, and quickly stirring it evenly, leaving it to cool, and after it becomes a hard block, gently taking it out of the porcelain crucible to obtain the microbial fuel cathode electrode material.

[0011] Furthermore, the specific process in step S4 is: breaking the bulk microbial fuel cathode electrode material into pieces smaller than 1 cm 3 Small pieces, packed into 4×4×4 cm 3 The microbial fuel is then placed in a small metal cage and connected to the cathode of the microbial fuel.

[0012] The cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification is prepared by the preparation method described in claims 1 to 7.

[0013] In the above technical scheme, sulfur powder is used as an electron donor for sulfur autotrophic denitrification to improve the denitrification capacity, graphite fiber and graphite powder increase the conductivity of electrode materials, and oyster shell powder provides a carbon source for the growth of microorganisms and can neutralize the H generated in the reactor. + , thereby stabilizing the pH value in the reactor; in order to make the powdered material after mixing the four raw materials into a stable electrode material that can firmly bind microorganisms, the mixture is further heat-treated into a liquid state. The addition of sodium bicarbonate acts as a foaming agent, increasing the specific surface area of ​​the electrode material, resulting in more microorganisms attached and stronger denitrification ability.

[0014] In summary, the raw materials used in the present invention are widely available and the preparation method is simple. The cathode electrode of the microbial fuel cell prepared by the method of the present invention has excellent performance, can improve the cathode redox reaction, enhance the electrochemical reversibility and reduce the charge transfer impedance, and improve the sulfur autotrophic denitrification denitrification capacity, and has the potential to improve microbial fuel cells and sulfur autotrophic denitrification. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a hard block structure diagram of the cathode electrode material of the microbial fuel cell prepared by the present invention.

[0016] Figure 2 The titanium wire mesh prepared in the present invention is 4×4×4 cm 3 Small cage.

[0017] Figure 3 The microbial fuel cathode electrode material prepared by the present invention is broken into pieces less than 1 cm 3 small pieces, packed into a 4×4×4 cm woven titanium wire mesh 3 The cathode structure of the microbial fuel in the small cage.

[0018] Figure 4 The scanning electron microscope images of the cathode material prepared by the present invention are magnified 1k times and 10k times.

[0019] Figure 5 This is an impedance analysis diagram of the cathode material of the microbial fuel cell prepared in the present invention.

[0020] Figure 6 The cyclic voltammetry curve of the cathode material of the microbial fuel cell prepared in the present invention. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0022] Embodiment 1 The preparation method of the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification comprises the following steps: S1. Clean the oyster shells with tap water, then clean them with ultrasonic vibration to thoroughly remove the surface dirt, dry them in an oven at 80°C for 24-32h to completely dry them, crush the dried oyster shells into powder with a grinder, and pass them through a 300-mesh sieve; S2. Grind the sulfur powder thoroughly and pass it through a 300-mesh sieve. Cut the graphite fiber into 1-2 mm long segments. Mix the sulfur powder, oyster shell powder, graphite powder and graphite fiber in a weight ratio of sulfur powder: oyster shell powder: graphite powder: graphite fiber 4:2:0.4:0.05 (S:OS:GP:GF4:2:0.4:0.05). S3. Put the above four substances mixed evenly into a 300 ml porcelain crucible, place it in a muffle furnace at 160℃ for heat treatment for 2 hours, take it out of the muffle furnace, immediately add 2.5% sodium bicarbonate of graphite powder in liquid state and stir it quickly to make the material foam inside to form a honeycomb to increase the contact area of ​​the reaction. After cooling into a hard block, gently take it out of the porcelain crucible to obtain the microbial fuel cathode electrode material, such as Figure 1 As shown; S4. Break the bulk microbial fuel cathode electrode material into pieces smaller than 1 cm 3 small pieces, packed into a 4×4×4 cm woven titanium wire mesh 3 Small cage ( Figure 2 ) and connected to the cathode of the microbial fuel to obtain ( Figure 3 ). Figure 4 Parts a and b are scanning electron microscope images of the cathode electrode of the microbial fuel cell for sulfur autotrophic denitrification coupled with electrochemical denitrification prepared in this embodiment at 2k times and 10k times.

[0023] Depend on Figure 4 In a and b, it can be found that when magnified 2k times, the surface of the cathode electrode material is rough with tiny holes, and the overall structure is thick and firm; when magnified 10k times, larger holes are obviously seen on the surface of the cathode electrode material, and the holes and other substances are inlaid.

[0024] In the three-electrode system, the prepared block of microbial fuel cathode electrode material was cut into small slices less than 1×1 cm as the working electrode, the saturated calomel electrode was the reference electrode, and the platinum electrode was the counter electrode. The AC impedance and cyclic voltammetry curves were measured. The results are as follows: Figure 5 and Figure 6 (a) shown.

[0025] like Figure 5 It can be seen that the impedance curve of the microbial fuel cathode electrode material prepared in this example has a larger arc, and its resistance value is also correspondingly larger.

[0026] like Figure 6 (a) It can be seen that the cyclic voltammetry curve of the microbial fuel cathode electrode material prepared in this example before being connected to the microbial fuel cell shows neither a reduction peak nor an oxidation peak.

[0027] Embodiment 2 The preparation method of the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification comprises the following steps: S1. Wash the oyster shells with tap water, then clean them with ultrasonic vibration to thoroughly remove the surface dirt, dry them in an oven at 80°C for 24-32 h to completely dry them, crush the dried oyster shells into powder with a grinder, and pass them through a 300-mesh sieve; S2. Grind the sulfur powder thoroughly and pass it through a 300-mesh sieve. Cut the graphite fiber into 1-2 mm long segments. Mix the sulfur powder, oyster shell powder, graphite powder and graphite fiber in a weight ratio of sulfur powder: oyster shell powder: graphite powder: graphite fiber 4:2:0.5:0.05 (S:OS:GP:GF4:2:0.5:0.05). S3. Put the above four substances mixed evenly into a 300ml porcelain crucible, place it in a muffle furnace at 160℃ for heat treatment for 2 hours, take it out of the muffle furnace and immediately add 2.5% sodium bicarbonate of graphite powder in liquid state and stir it quickly to make the material foam inside to form a honeycomb to increase the contact area of ​​the reaction. After cooling into a hard block, gently take it out of the porcelain crucible to obtain the microbial fuel cathode electrode material, such as Figure 1 As shown; S4. Break the bulk microbial fuel cathode electrode material into pieces smaller than 1 cm 3 small pieces, packed into a 4×4×4 cm woven titanium wire mesh 3 Small cage ( Figure 2 ) and connected to the cathode of the microbial fuel to obtain ( Figure 3 ). Figure 4 Middle b is a scanning electron microscope image of the cathode electrode of the microbial fuel cell for sulfur autotrophic denitrification coupled with electrochemical denitrification prepared in this embodiment.

[0028] Depend on Figure 4 In c and d, it can be found that when the magnification is 2k times, the surface of the cathode electrode material is rough, and the overall structure is thick and firm; when the magnification is 10k times, some holes are clearly seen on the surface of the cathode electrode material.

[0029] In the three-electrode system, the prepared block of microbial fuel cathode electrode material was cut into small slices less than 1×1 cm as the working electrode, the saturated calomel electrode was the reference electrode, and the platinum electrode was the counter electrode. The AC impedance and cyclic voltammetry curves were measured. The results are as follows: Figure 5 and Figure 6 (b) shown.

[0030] like Figure 5 It can be seen that the impedance curve of the microbial fuel cathode electrode material prepared in this example has a smaller arc, its resistance value is correspondingly smaller, and the electron transfer effect is good.

[0031] like Figure 6 (b) It can be seen that the cyclic voltammetry curve of the microbial fuel cathode electrode material prepared in this example before being connected to the microbial fuel cell shows neither a reduction peak nor an oxidation peak.

[0032] Embodiment 3 The preparation method of the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification comprises the following steps: S1. Wash the oyster shells with tap water, then clean them with ultrasonic vibration to thoroughly remove the surface dirt, dry them in an oven at 80°C for 24-32 h to completely dry them, crush the dried oyster shells into powder with a grinder, and pass them through a 300-mesh sieve; S2. Grind the sulfur powder thoroughly and pass it through a 300-mesh sieve. Cut the graphite fiber into 1-2 mm long segments. Mix the sulfur powder, oyster shell powder, graphite powder and graphite fiber in a weight ratio of sulfur powder: oyster shell powder: graphite powder: graphite fiber 4:2:0.6:0.05 (S:OS:GP:GF4:2:0.6:0.05) evenly. S3. Put the above four substances mixed evenly into a 300 ml porcelain crucible, place it in a muffle furnace at 160℃ for heat treatment for 2 hours, take it out of the muffle furnace, immediately add 2.5% sodium bicarbonate of graphite powder in liquid state and stir it quickly to make the material foam inside to form a honeycomb to increase the contact area of ​​the reaction. After cooling into a hard block, gently take it out of the porcelain crucible to obtain the microbial fuel cathode electrode material, such as Figure 1 As shown; S4. Break the bulk microbial fuel cathode electrode material into pieces smaller than 1 cm 3 small pieces, packed into a 4×4×4 cm woven titanium wire mesh 3 Small cage ( Figure 2 ) and connected to the cathode of the microbial fuel to obtain ( Figure 3 ). Figure 4 (c) is a scanning electron microscope image of the cathode electrode of the microbial fuel cell for sulfur autotrophic denitrification coupled with electrochemical denitrification prepared in this embodiment.

[0033] Depend on Figure 4 From e and f, it can be found that the surface of the cathode electrode material is rough when magnified 2k times; and more holes are obviously seen on the surface of the cathode electrode material when magnified 10k times, and the overall structure is thick and firm.

[0034] In the three-electrode system, the prepared block of microbial fuel cathode electrode material was cut into small slices less than 1×1 cm as the working electrode, the saturated calomel electrode was the reference electrode, and the platinum electrode was the counter electrode. The AC impedance and cyclic voltammetry curves were measured. The results are as follows: Figure 5 and Figure 6 (c) shown.

[0035] like Figure 5 It can be seen that the impedance curve of the microbial fuel cathode electrode material prepared in this example has a small arc, its resistance value is correspondingly small, and the electron transfer effect is better.

[0036] like Figure 6 (c) It can be seen that the cyclic voltammetry curve of the microbial fuel cathode electrode material prepared in this example before being connected to the microbial fuel cell shows neither reduction peak nor oxidation peak.

[0037] Embodiment 4 The preparation method of the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification comprises the following steps: S1. Wash the oyster shells with tap water, then clean them with ultrasonic vibration to thoroughly remove the surface dirt, dry them in an oven at 80°C for 24-32 h to completely dry them, crush the dried oyster shells into powder with a grinder, and pass them through a 300-mesh sieve; S2. Grind the sulfur powder thoroughly and pass it through a 300-mesh sieve. Cut the graphite fiber into 1-2 mm long segments. Mix the sulfur powder, oyster shell powder, graphite powder and graphite fiber in a weight ratio of sulfur powder: oyster shell powder: graphite powder: graphite fiber 4:2:0.7:0.05 (S:OS:GP:GF4:2:0.7:0.05). S3. Put the above four substances mixed evenly into a 300ml porcelain crucible, place it in a muffle furnace at 160℃ for heat treatment for 2 hours, take it out of the muffle furnace and immediately add 2.5% sodium bicarbonate of graphite powder in liquid state and stir it quickly to make the material foam inside to form a honeycomb to increase the contact area of ​​the reaction. After cooling into a hard block, gently take it out of the porcelain crucible to obtain the microbial fuel cathode electrode material, such as Figure 1 As shown; S4. Break the bulk microbial fuel cathode electrode material into pieces smaller than 1 cm 3 small pieces, packed into a 4×4×4 cm woven titanium wire mesh 3 Small cage ( Figure 2 ) and connected to the cathode of the microbial fuel to obtain ( Figure 3 ). Figure 4(d) is a scanning electron microscope image of the cathode electrode of the microbial fuel cell for sulfur autotrophic denitrification coupled with electrochemical denitrification prepared in this embodiment.

[0038] Depend on Figure 4 In g and h, it can be found that the surface of the cathode electrode material is rough when magnified 2k times; when magnified 10k times, many holes are clearly seen on the surface of the cathode electrode material, and the overall structure is thick and firm.

[0039] In the three-electrode system, the prepared block of microbial fuel cathode electrode material was cut into small slices less than 1×1 cm as the working electrode, the saturated calomel electrode was the reference electrode, and the platinum electrode was the counter electrode. The AC impedance and cyclic voltammetry curves were measured. The results are as follows: Figure 5 and Figure 6 (d) shown.

[0040] like Figure 5 It can be seen that the impedance curve of the microbial fuel cathode electrode material prepared in this example has a small arc, its resistance value is correspondingly small, and the electron transfer effect is better.

[0041] like Figure 6 (d) It can be seen that the cyclic voltammetry curve of the microbial fuel cathode electrode material prepared in this example before being connected to the microbial fuel cell shows neither reduction peak nor oxidation peak.

[0042] Embodiment 5 The preparation method of the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification comprises the following steps: S1. Wash the oyster shells with tap water, then clean them with ultrasonic vibration to thoroughly remove the surface dirt, dry them in an oven at 80°C for 24-32 h to completely dry them, crush the dried oyster shells into powder with a grinder, and pass them through a 300-mesh sieve; S2. Grind the sulfur powder thoroughly and pass it through a 300-mesh sieve. Cut the graphite fiber into 1-2 mm long segments. Mix the sulfur powder, oyster shell powder, graphite powder and graphite fiber in a weight ratio of sulfur powder: oyster shell powder: graphite powder: graphite fiber 4:2:0.8:0.05 (S:OS:GP:GF4:2:0.8:0.05) evenly. S3. Put the above four substances mixed evenly into a 300 ml porcelain crucible, place it in a muffle furnace at 160 ° C for heat treatment for 2 h, take it out of the muffle furnace, immediately add 2.5% sodium bicarbonate of graphite powder in liquid state and stir it quickly to make the material foam inside to form a honeycomb to increase the contact area of ​​the reaction. After cooling into a hard block, gently take it out of the porcelain crucible to obtain the microbial fuel cathode electrode material, such as Figure 1 shown.

[0043] S4. Break the bulk microbial fuel cathode electrode material into pieces smaller than 1 cm 3 small pieces, packed into a 4×4×4 cm woven titanium wire mesh 3 Small cage ( Figure 2 ) and connected to the cathode of the microbial fuel to obtain ( Figure 3 ). Figure 4 (e) is a scanning electron microscope image of the cathode electrode of the microbial fuel cell for sulfur autotrophic denitrification coupled with electrochemical denitrification prepared in this embodiment.

[0044] Depend on Figure 4 From i and j in the figure, it can be found that the surface of the cathode electrode material is rough when magnified 2k times; many holes are clearly seen on the surface of the cathode electrode material when magnified 10k times, and the overall structure is thick and firm.

[0045] In the three-electrode system, the prepared block of microbial fuel cathode electrode material was cut into small slices less than 1×1 cm as the working electrode, the saturated calomel electrode was the reference electrode, and the platinum electrode was the counter electrode. The AC impedance and cyclic voltammetry curves were measured. The results are as follows: Figure 5 and Figure 6 (e) shown.

[0046] like Figure 5 It can be seen that the impedance curve of the microbial fuel cathode electrode material prepared in this example has a small arc, its resistance value is correspondingly small, and the electron transfer effect is better.

[0047] like Figure 6 (e) It can be seen that the cyclic voltammetry curve of the microbial fuel cathode electrode material prepared in this example before being connected to the microbial fuel cell shows neither reduction peak nor oxidation peak.

[0048] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials in the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification, characterized in that: The following steps are involved: S1, preparing oyster shell powder; S2. Evenly mix sulfur powder, oyster shell powder, graphite powder and graphite fiber according to a certain proportion; S3, subjecting the uniformly mixed mixture of the above four raw materials to a series of treatment steps to obtain a block-shaped microbial fuel cathode electrode material; S4. Crushing the bulk microbial fuel cathode electrode material before use.

2. The method for preparing the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification according to claim 1, characterized in that: The specific process of preparing oyster shell powder in step S1 is as follows: clean the oyster shell with tap water, then clean it with ultrasonic vibration to thoroughly remove the surface dirt, bake it in an oven at 80° C. for 24-32 h until it is completely dry, and crush the dried oyster shell into powder with a grinder and pass it through a 300-mesh sieve.

3. The method for preparing the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification according to claim 1, characterized in that: The sulfur powder in step S2 is obtained by fully grinding the purchased sulfur powder and passing it through a 300-mesh sieve.

4. The method for preparing the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification according to claim 1, characterized in that: The graphite fibers in step S2 are obtained by cutting or shearing the graphite fiber strands into pieces with a length of 1-2 mm.

5. The method for preparing the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification according to claim 1, characterized in that: The certain proportion in step S2 refers to a weight ratio of oyster shell powder: graphite powder: graphite fiber equal to 4:2:0.4:0.

05.

6. The method for preparing the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification according to claim 1, characterized in that: The specific process in step S3 is: put the mixture into a 300 mL porcelain crucible, place it in a muffle furnace at 160°C for heat treatment for 2 hours, take it out from the muffle furnace, immediately add a corresponding amount of sodium bicarbonate while the mixture is in a liquid state, and quickly stir it evenly, let it cool, and after it becomes a hard block, gently take it out of the porcelain crucible to obtain the microbial fuel cathode electrode material.

7. The method for preparing the cathode electrode of a microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification according to claim 1, characterized in that: The specific process of step S4 is: breaking the bulk microbial fuel cathode electrode material into pieces smaller than 1 cm 3 Small pieces, packed into 4×4×4 cm 3 The microbial fuel is then placed in a small metal cage and connected to the cathode of the microbial fuel.

8. The cathode electrode of the microbial fuel cell based on sulfur autotrophic denitrification coupled with electrochemical denitrification according to claim 1, characterized in that: The invention is prepared by the preparation method described in claims 1 to 7.

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