CN108448144B - Microbial fuel cell - Google Patents

Abstract

The invention provides a microbial fuel cell, comprising a first anode chamber, a cathode chamber and a second anode chamber arranged in sequence, separated by a cation exchange membrane and an anion exchange membrane respectively, and the first anode chamber and the second anode chamber are also communicated with each other The first anode, the cathode and the second anode are respectively connected; the first anode is inoculated with microorganisms or activated sludge with electricity-generating activity, the cathode is provided with a non-biological catalyst, and the catholyte in the cathode chamber is inoculated with nitrification activity. Microorganisms or activated sludge, the second anode is inoculated with microorganisms or activated sludge that have both electricity production and denitrification activities. The invention guarantees the optimum environment for the power generation efficiency, the nitrification efficiency and the denitrification efficiency respectively, and on the basis of the effective removal of organic matter in the wastewater, the effective removal of nitrogen in the wastewater is also ensured.

Description

A microbial fuel cell

technical field

The invention relates to the technical field of microbial electrochemistry, in particular to a microbial fuel cell.

Background technique

At present, with the rapid development of my country's economy, the increasingly frequent industrial production activities and human activities have caused serious water pollution, and also consumed a lot of energy; today's water pollution and energy shortage have become the key problems restricting my country's sustainable development .

Microbial Fuel Cell (MFC) is a new type of clean energy technology that uses electricity-generating microorganisms to degrade organic pollutants in water and convert their chemical energy into electricity in situ. The use of microbial fuel cells to treat wastewater not only achieves effective removal of organic matter, but also directly converts chemical energy into electrical energy, which not only solves the shortcomings of high energy consumption and large sludge output in traditional wastewater treatment, but also effectively recovers a large amount of organic matter in wastewater. Potential chemical energy is gradually applied in the field of wastewater treatment.

In practical applications, although traditional microbial fuel cells can effectively remove organic matter in wastewater, the nitrogen removal effect in wastewater is still not ideal, especially the removal of nitrate, and its removal rate is far cannot meet demand.

SUMMARY OF THE INVENTION

The present invention provides a microbial fuel cell to solve the problem that the microbial fuel cell in the prior art cannot effectively remove nitrogen in wastewater.

An embodiment of the present invention provides a microbial fuel cell, comprising a first anode compartment, a cathode compartment and a second anode compartment arranged in sequence, the first anode compartment and the cathode compartment are separated by a cation exchange membrane, and the cathode compartment and the second anode chamber are separated by an anion exchange membrane, and the first anode chamber and the second anode chamber are also communicated with each other; the first anode in the first anode chamber, the cathode in the cathode chamber and the second anodes located in the second anode chamber are respectively connected;

The first anode is inoculated with microorganisms or activated sludge with electricity generating activity, the cathode is provided with non-biological catalysts, and the catholyte in the cathode chamber is inoculated with microorganisms or activated sludge with nitrification activity. The second anode is inoculated with microorganisms or activated sludge that have both electricity production and denitrification activities.

As a preferred mode of the present invention, the first anode chamber includes a first water inlet and a first water outlet, the second anode chamber includes a second water inlet and a second water outlet, wherein the first water outlet and all The second water inlet is connected through a conduit, and the first water inlet is connected with an external waste water supply device.

As a preferred mode of the present invention, the concentrations of dissolved oxygen in the anolyte in the first anode chamber and in the anolyte in the second anode chamber are both 0.05 to 0.1 mg/L.

As a preferred mode of the present invention, an aeration tube is provided in the cathode chamber, and the other end of the aeration tube is connected to an external air pump.

As a preferred mode of the present invention, a gas flow meter is further provided between the aeration pipe and the air pump, and the aeration rate is controlled to be 10-50 ml/min by the gas flow meter.

As a preferred mode of the present invention, the non-biological catalyst provided on the cathode is a Pt or nitrogen-doped graphene catalyst.

As a preferred mode of the present invention, the catholyte is an inorganic salt solution or a nitrogen-containing inorganic salt solution.

As a preferred mode of the present invention, the culture temperature of the first anode chamber, the cathode chamber and the second anode chamber is 30°C.

As a preferred mode of the present invention, the volumes of the first anode chamber, the cathode chamber and the second anode chamber are the same.

As a preferred mode of the present invention, the first anode, the cathode and the second anode are made of carbon paper, carbon cloth, carbon felt, graphite felt or graphite plate material.

The microbial fuel cell provided by the invention adopts the structure of two anode chambers and one cathode chamber, and realizes the rapid separation of nitrogen from wastewater in the first anode chamber to reduce the electricity generation activity in the first anode chamber. At the same time, the nitrification reaction and denitrification reaction of denitrification are separated, so that the nitrification reaction occurs in the cathode chamber, and the denitrification reaction occurs in the second anode chamber, thereby ensuring the power generation efficiency, nitrification efficiency and reverse reaction respectively. The optimum environment for nitrification efficiency ensures the effective removal of nitrogen in wastewater on the basis of effective removal of organic matter in wastewater.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a schematic structural diagram of a microbial fuel cell provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of a voltage output of a microbial fuel cell provided by an embodiment of the present invention;

3 is a schematic diagram of COD changes of the first anode chamber and the second anode chamber in the microbial fuel cell provided by the embodiment of the present invention;

4 is a schematic diagram of changes in ammonia nitrogen concentration in a first anode chamber, a cathode chamber and a second anode chamber in a microbial fuel cell provided by an embodiment of the present invention;

FIG. 5 is a schematic diagram showing the change of nitrate nitrogen concentration in the first anode chamber, the cathode chamber and the second anode chamber in the microbial fuel cell according to the embodiment of the present invention.

Among them, 1, the first anode chamber, 2, the cathode chamber, 3, the second anode chamber, 4, the cation exchange membrane, 5, the anion exchange membrane, 6, the first anode, 7, the cathode, 8, the second anode, 9 , The first water inlet, 10, the first water outlet, 11, the second water inlet, 12, the second water outlet, 13, the conduit, 14, the aeration pipe, 15, the gas flow meter.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only Embodiments are part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Referring to FIG. 1 , an embodiment of the present invention discloses a microbial fuel cell, comprising a first anode chamber 1, a cathode chamber 2 and a second anode chamber 3 arranged in sequence, and the first anode chamber 1 and the cathode chamber 2 pass through cation exchange The membrane 4 is separated, the cathode chamber 2 and the second anode chamber 3 are separated by an anion exchange membrane 5, and the first anode chamber 1 and the second anode chamber 3 are also communicated with each other; The cathode 7 located in the cathode chamber 2 and the second anode 8 located in the second anode chamber 3 are respectively connected; the first anode 6 is inoculated with microorganisms or activated sludge with electricity generating activity, and the cathode 7 is provided with a non-biological catalyst , the catholyte in the cathode chamber 2 is inoculated with microorganisms or activated sludge with nitrification activity, and the second anode 8 is inoculated with microorganisms or activated sludge with both electricity generation and denitrification activities.

In this embodiment, the wastewater treated by the microbial fuel cell refers to wastewater containing organic matter and nitrogen, where nitrogen generally refers to ammonia nitrogen in wastewater, and ammonia nitrogen refers to free ammonia (NH ₃ ^- ) and ammonium ions ( nitrogen in the form of NH ₄ ⁺ ). Traditional microbial fuel cells mainly achieve the removal of organic matter in wastewater, but the removal effect of nitrogen in wastewater is not ideal, especially the removal of nitrate, and the removal rate is far from meeting the demand.

The microbial fuel cell provided by the embodiment of the present invention adopts the structure of two anode chambers and one cathode chamber. After the waste water enters the first anode chamber, the organic matter in the first anode chamber is degraded and electrons are released, and the electrons reach the cathode through the external circuit , the nitrogen in it quickly enters the cathode chamber through the cation exchange membrane, and forms nitrate under the action of microorganisms in the cathode chamber, and the oxygen reduction reaction occurs in the cathode chamber under the action of the catalyst to consume the electrons from the anode; The anion exchange membrane enters the second anode chamber, and is finally reduced to nitrogen in the second anode chamber. At the same time, the waste water further enters the second anode chamber. The organic matter is further degraded in the second anode chamber and releases electrons, and the electrons also reach the external circuit. cathode.

The microbial fuel cell realizes the rapid separation of nitrogen from wastewater in the first anode chamber to reduce the poisoning effect on microorganisms with electricity-generating activity in the first anode chamber, and simultaneously separates the nitrification reaction and denitrification reaction of denitrification. , so that the nitrification reaction occurs in the cathode chamber, and the denitrification reaction occurs in the second anode chamber, thereby ensuring the optimal environment for the power generation efficiency, nitrification efficiency and denitrification efficiency respectively. Effective removal of nitrogen from wastewater is ensured.

At the same time, the organic matter in the wastewater is fully degraded and converted into electrical energy for use by external electrical equipment through an external circuit.

In this embodiment, the microorganisms or activated sludge with electricity-generating activity inoculated on the first anode, the microorganisms or activated sludge with nitrification activity inoculated in the catholyte, and the inoculated on the second anode have both electricity-generating and denitrifying properties The activated microorganisms or activated sludges all use microorganisms or activated sludges commonly used in the prior art, which are not specifically limited in the embodiment of the present invention.

Further, the nitrogen in the wastewater in the first anode chamber quickly migrates to the cathode through the cation exchange membrane, which reduces the inhibition of nitrogen on the activity of microorganisms with electricity-generating activity, so that the first anode in the first anode chamber can be effectively improved. power generation performance.

Further, the cathode uses non-biological catalysts to catalyze the oxygen reduction reaction to generate electricity efficiently, and at the same time, the nitrification reaction is carried out by using microorganisms with nitrification activity or activated sludge inoculated in the catholyte, which can release protons and neutralize the oxygen consumption at the cathode. Protons can effectively alleviate the increase of catholyte pH, do not affect the catalytic activity of microorganisms, and ensure the effective removal of nitrogen; and microorganisms with nitrification activity can form biofilms on the surface of abiotic catalysts, effectively preventing abiotic catalysts from falling off and loss, extending the effective life of the cathode, thereby reducing the cost of microbial fuel cells. In traditional microbial fuel cells, when abiotic catalysts are used in the cathode, the service life of the cathode is greatly shortened due to the shedding and loss of the abiotic catalysts during operation, thereby increasing the cost of the microbial fuel cell. The separation membrane between the two reduces the transport of protons, which leads to the acid-base imbalance in the cathode and anode chambers during long-term operation, which affects the catalytic activity of microorganisms. Although the pH change can be effectively alleviated by the buffer system, it still cannot be solved in essence. The problem of acid-base imbalance.

Further, the second anode chamber mainly conducts denitrification reaction, which can quickly reduce nitrate, and the generated hydroxide neutralizes the anolyte acidified in the early stage, effectively alleviates the increase of catholyte pH, does not affect the catalytic activity of microorganisms, and ensures It can effectively remove nitrogen; and can further degrade the organic matter in the anolyte and release electrons to the cathode, and further improve the power generation performance.

On the basis of the above embodiment, the first anode chamber 1 includes a first water inlet 9 and a first water outlet 10, and the second anode chamber 3 includes a second water inlet 11 and a second water outlet 12, wherein the first water outlet 10 It is connected with the second water inlet 11 through a conduit 13, and the first water inlet 9 is connected with an external waste water supply device.

In this embodiment, the waste water is introduced from the waste water supply device and enters the first anode chamber through the first water inlet, where the organic matter is degraded and electrons are released, and the nitrogen in it enters the cathode quickly through the cation exchange membrane The treated wastewater in the first anode chamber also enters the second anode chamber through the first water outlet, the conduit and the second water inlet in turn, further degrades the residual organic matter in the wastewater and generates electrons, while in the cathode chamber Nitrate formed by nitrogen also enters the second anode chamber through the anion exchange membrane for denitrification reaction, which can not only effectively remove organic matter in wastewater, but also separate the environment of nitrification reaction and denitrification reaction, so as to effectively remove wastewater nitrogen in. Finally, the treated wastewater that meets the standard is discharged through the second water outlet.

On the basis of the above embodiment, the concentration of dissolved oxygen in the anolyte in the first anode chamber 1 and the anolyte in the second anode chamber 3 is both 0.05-0.1 mg/L.

In this embodiment, the first anode chamber and the second anode chamber are anaerobic closed environments, so when the dissolved oxygen concentration in the anolyte in the first anode chamber and the second anode chamber is 0.05-0.1 mg/L, the Under the action of microorganisms, the organic matter is decomposed better and electrons are released, and the electricity generation performance of the anode is improved.

On the basis of the above embodiment, the cathode chamber 2 is provided with an aeration tube 14, and the other end of the aeration tube 14 is connected to an external air pump.

In this embodiment, the cathode chamber is an aerobic aeration environment, so an aeration tube is set in the cathode chamber, and one end of the aeration tube extends into the catholyte, and the other end is connected to an external air pump, which can ensure the cathode The dissolved oxygen in the indoor catholyte is sufficient.

On the basis of the above embodiment, a gas flow meter 15 is further arranged between the aeration pipe 14 and the air pump, and the aeration rate is controlled to be 10-50 ml/min by the gas flow meter 15 .

In this embodiment, in order to better control the aeration volume, a gas flow meter is set between the aeration pipe and the air pump, and when the aeration volume is controlled to 10-50ml/min by the gas flow meter, the cathode can be The content of dissolved oxygen in the liquid is optimal, which is beneficial to the nitrification of nitrogen by microorganisms with nitrification activity in the catholyte.

On the basis of the above embodiment, the non-biological catalyst arranged on the cathode 7 is a Pt or nitrogen-doped graphene catalyst.

In this embodiment, the non-biological catalyst arranged on the cathode is a Pt or nitrogen-doped graphene catalyst, which has good catalytic performance and can effectively realize the catalytic effect of the cathode during redox reaction.

On the basis of the above embodiments, the catholyte is an inorganic salt solution or a nitrogen-containing inorganic salt solution.

In this embodiment, the catholyte is preferably an inorganic salt solution or a nitrogen-containing inorganic salt solution, which can better provide an inoculation environment and a growth environment for microorganisms or activated sludge with nitrification activity.

On the basis of the above embodiment, the incubation temperature of the first anode chamber 1 , the cathode chamber 2 and the second anode chamber 3 is 30°C.

In this embodiment, the culture temperature of the first anode chamber, the cathode chamber and the second anode chamber is controlled to be 30°C, thereby indirectly adjusting the temperature of the surfaces of the first anode and the second anode and the temperature of the catholyte to 30°C, which can be Microorganisms provide the most suitable growth environment, improve the biological activity of microorganisms, and ultimately improve the performance of the entire microbial fuel cell. In practical application, the whole of the first anode chamber, the cathode chamber and the second anode chamber can be put into a constant temperature incubator for constant temperature cultivation at 30°C.

On the basis of the above embodiment, the volumes of the first anode chamber 1 , the cathode chamber 2 and the second anode chamber 3 are the same.

In this embodiment, since the migration rate of anions and cations by the anion and cation exchange membrane is related to the volume and ion concentration of the electrode chamber, the nitrification reaction rate of the cathode chamber is determined by the migration rate of the first anode chamber to the cathode chamber. Protons can be used as a source of protons for the cathode oxygen reduction reaction; the denitrification reaction rate of the second anode chamber depends on the migration rate of the cathode chamber to the second anode chamber and the concentration of organic matter migrated from the first anode chamber to the second anode chamber; when the three When the volume of the two is the same, it is beneficial to the nitrification and denitrification reactions of nitrogen in the wastewater, and the removal rate of organic matter and nitrogen in the discharged wastewater can be guaranteed to be more than 95%.

On the basis of the above embodiments, the first anode 6 , the cathode 7 and the second anode 8 are made of carbon paper, carbon cloth, carbon felt, graphite felt or graphite plate material.

In this embodiment, the first anode, the cathode and the second anode are all made of carbon paper, carbon cloth, carbon felt, graphite felt or graphite plate materials. These materials have better electrical conductivity and are easier to attach to microorganisms. Material cost is low and easy to obtain.

To further illustrate the technical solution of the present invention, the embodiment of the present invention also provides a specific implementation of a microbial fuel cell.

In this embodiment, the microbial fuel cell consists of a first anode chamber and a second anode chamber with a volume of 100ml and a cathode chamber with a volume of 100ml, wherein the cathode chamber is located in the middle of the first anode chamber and the second anode chamber, And the first anode compartment and the cathode compartment are separated by a cation exchange membrane, and the cathode compartment and the second anode compartment are separated by an anion exchange membrane. The first anode located in the first anode chamber and the second anode located in the second anode chamber are respectively connected to the cathode located in the cathode chamber through wires through an external resistance of 1 kΩ to form a current loop.

Both the first anode and the second anode are made of carbon felt material, and the size of the carbon felt is 2 × 3 × 3 cm, and the activated sludge with electricity-generating activity is inoculated on the first anode, and the activated sludge with electricity-producing activity is inoculated on the second anode. For activated sludge with electricity and denitrification activities, the inoculum amount of activated sludge is 0.5 mg/ml. The cathode is made of carbon cloth material, and is loaded with 0.5 mg/cm ² of Pt-doped graphene catalyst. The size of the carbon cloth is 3 × 3 cm, and activated sludge with nitrification activity is inoculated in the catholyte in the cathode chamber. The inoculum was 0.5 mg/ml. Both the first anode chamber and the second anode chamber are anaerobic closed environments, and the concentration of dissolved oxygen in the anode solution is both 0.05-0.1 mg/L. The cathode chamber is an aerobic aeration environment, and the aeration volume is controlled at 30-40ml/min by an air pump flowing through a gas flow meter.

The first anode chamber includes a first water inlet and a first water outlet, the second anode chamber includes a second water inlet and a second water outlet, wherein the first water outlet and the second water inlet are connected by a conduit, and the first water inlet is connected to the outside connected to the waste water supply.

In the first anode chamber and the second anode chamber, the simulated nitrogen-containing organic wastewater is added as the anolyte, wherein the main components and proportions of the anolyte in the second anode chamber are: sodium dihydrogen phosphate dihydrate (Na ₂ HPO ₄ 2H ₂ O) 0.8～8.1g/L, disodium hydrogen phosphate dodecahydrate (Na ₂ HPO ₄ 12H ₂ O) 2.1～22g/L, potassium chloride (KCl) 0～0.26g/L, sodium acetate (CH ₃ COONa) 0.5 g/L, Wolfes mineral solution 10 mL/L, and its pH value was adjusted to 7 by HCl solution or NaOH solution. Wherein, the specific composition of Wolfes mineral solution is: aminoacetic acid (NH ₂ CH ₂ COOH) 1.5g/L, magnesium sulfate heptahydrate (MgSO ₄ ·7H ₂ O) 3g/L, manganese sulfate dihydrate (MnSO ₄ ·2H _{2 )} O) 0.5g/L, sodium chloride (NaCl) 1.0g/L, ferrous sulfate heptahydrate (FeSO ₄ ·7H ₂ O) 0.1g/L, cobalt chloride (CoCl ₂ ) 0.1g/L, chloride Calcium (CaCl ₂ ) 0.1 g/L, zinc sulfate (ZnSO ₄ ) 0.1 g/L, copper sulfate pentahydrate CuSO ₄ 5H ₂ O 0.01 g/L, anhydrous aluminum potassium sulfate (AlK(SO ₄ ) ₂ ) 0.01 g/L, boric acid (H ₃ BO ₃ ) 0.01 g/L, sodium molybdate (Na ₂ MoO ₄ ·2H ₂ O) 0.01 g/L, and the pH was adjusted to 7 by KOH solution. The anolyte in the first anode chamber was based on the anolyte in the second anode chamber, and ammonium chloride (NH ₄ Cl) 0.42 g/L was added as a nitrogen source.

The main components and proportions of the catholyte in the cathode compartment are: sodium dihydrogen phosphate dihydrate (Na ₂ HPO ₄ ·2H ₂ O) 0.8-8.1 g/L, sodium hydrogen phosphate dodecahydrate (Na ₂ HPO ₄ ) 0.8-8.1 g/L ·12H ₂ O) 2.1～22g/L phosphate buffer solution.

When using, the corresponding solution was added to each chamber at one time, mixed with activated sludge, placed in a 30°C constant temperature incubator for cultivation, and a data acquisition card was connected to the electrode to record the acquisition voltage every 5 minutes. When the voltage first rises and then drops below 20mV, it is regarded as a complete cycle and needs to be replaced with a new solution. After the first 3 cycles of operation, the output voltage of the entire microbial fuel cell is stable. The voltage output during the fourth cycle of operation is shown in Figure 2. The maximum output voltage collected by the first anode and cathode is as high as 620mV. After the solution was replaced, the voltage rose rapidly, and the voltage changes of the second anode and cathode were consistent with it.

Fig. 3 is a schematic diagram of COD changes of the first anode chamber and the second anode chamber in the microbial fuel cell provided by the embodiment of the present invention. It can be seen from Fig. 3 that the initial COD ( ChemicalOxygen Demand) values are all around 500mg/L. As the whole operation process continues, the COD value in the first anode chamber decreases at a uniform speed, while the COD value in the second anode chamber under the same concentration is in the early stage. Quick solution.

Fig. 4 is a schematic diagram showing the change of ammonia nitrogen concentration in the first anode chamber, the cathode chamber and the second anode chamber in the microbial fuel cell provided by the embodiment of the present invention, and Fig. 5 is the first anode chamber and the cathode of the microbial fuel cell provided by the embodiment of the present invention Schematic diagram of the change of nitrate nitrogen concentration in the chamber and the second anode chamber. It can be seen from the nitrogen changes in Figures 4 and 5 that ammonia nitrogen migrates from the first anode chamber to the cathode chamber, and the ammonia nitrogen in the cathode chamber does not accumulate but is rapidly converted into nitrate. In addition, when nitrate migrates from the cathode compartment to the second anode compartment, the reduction reaction of nitrate also occurs rapidly, so that the nitrate concentration in the second anode compartment is maintained at a low level. It can also be seen from Figures 4 and 5 that the nitrification reaction in the cathode compartment and the denitrification reaction in the second anode compartment are at a faster rate without substrate accumulation.

The microbial fuel cell provided by the embodiment of the present invention has a simple structure and is easy to operate. On the basis of the effective removal of organic matter in the wastewater, it also ensures the effective removal of nitrogen in the wastewater, and can also effectively prevent the abiotic catalyst from falling off and running off. , extending the effective life of the cathode, thereby reducing the cost of microbial fuel cells.

In the above-mentioned embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (9)

1. A microbial fuel cell is characterized by comprising a first anode chamber, a cathode chamber and a second anode chamber which are sequentially arranged, wherein the first anode chamber and the cathode chamber are separated by a cation exchange membrane, the cathode chamber and the second anode chamber are separated by an anion exchange membrane, and the first anode chamber and the second anode chamber are also communicated with each other; the first anode positioned in the first anode chamber, the cathode positioned in the cathode chamber and the second anode positioned in the second anode chamber are respectively connected;

microorganisms or activated sludge with electrogenesis activity are inoculated on the first anode, a non-biological catalyst is arranged on the cathode, microorganisms or activated sludge with nitrification activity are inoculated in catholyte in the cathode chamber, and microorganisms or activated sludge with electrogenesis and denitrification activity are inoculated on the second anode;

the volumes of the first anode chamber, the cathode chamber and the second anode chamber are the same.

2. The microbial fuel cell of claim 1, wherein the first anode chamber comprises a first water inlet and a first water outlet, the second anode chamber comprises a second water inlet and a second water outlet, wherein the first water outlet and the second water inlet are connected by a conduit, and the first water inlet is connected to an external wastewater supply.

3. The microbial fuel cell according to claim 1, wherein an aeration pipe is arranged in the cathode chamber, and the other end of the aeration pipe is connected with an external air pump.

4. The microbial fuel cell according to claim 3, wherein a gas flow meter is further provided between the aeration pipe and the air pump, and the aeration amount is controlled to be 10-50 ml/min by the gas flow meter.

5. The microbial fuel cell of claim 1, wherein the non-biological catalyst disposed on the cathode is a Pt or nitrogen doped graphene catalyst.

6. The microbial fuel cell of claim 1, wherein the catholyte is an inorganic salt solution or a nitrogen-containing inorganic salt solution.

7. The microbial fuel cell of claim 1, wherein the incubation temperature of the first anode chamber, the cathode chamber, and the second anode chamber is 30 ℃.

8. The microbial fuel cell according to claim 1, wherein the concentration of dissolved oxygen in the anolyte in the first anode chamber and the anolyte in the second anode chamber are both 0.05 to 0.1 mg/L.

9. The microbial fuel cell of claim 1, wherein the first anode, the cathode, and the second anode are made of carbon paper, carbon cloth, carbon felt, graphite felt, or graphite plate material.

Images