A microbial fuel cell with a conductive dynamic membrane separator and its application

Abstract

The application discloses a microbial fuel cell with a conductive dynamic membrane separator and application thereof. The microbial fuel cell comprises a reaction chamber, a conductive dynamic membrane separator is arranged in the reaction chamber, the conductive dynamic membrane separator divides the reaction chamber into a cathode chamber and an anode chamber, and the conductive dynamic membrane separator is electrically connected with the cathode chamber or the anode chamber; the conductive dynamic membrane separator comprises, from inside to outside, a dynamic membrane, a metal current collecting grid and an oxygen isolation layer in sequence, the dynamic membrane comprises a frame material and a base film, the frame material is used for supporting the base film, and the base film is made of conductive porous material. The microbial fuel cell has the metal current collecting grid as a framework, which not only plays a supporting role, but also has a current collecting function. The ingenious design of the fuel cell structure of the scheme not only remarkably improves water quality and oxygen isolation effect, but also reduces the manufacturing cost of an exchange film, and has wide application potential in the fields of sewage treatment and reclaimed water reuse.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment and resource recovery technology, and in particular to a microbial fuel cell with a conductive dynamic membrane separator and its application. Background Technology

[0002] Water resources, as the cornerstone of human survival and social development, are of paramount importance for protection and sustainable utilization. Therefore, humanity must attach great importance to and commit to developing efficient wastewater treatment and reuse technologies. This is not only an urgent need to alleviate environmental pressure and protect ecological balance, but also a crucial pathway to achieving sustainable development.

[0003] Microbial fuel cells (MFCs) utilize organic pollutants as anode fuel, converting biomass energy into electrical energy through the catalytic action of microorganisms. This achieves an organic combination of wastewater treatment and power generation, providing a new approach to wastewater resource utilization. However, in practical applications, MFC technology still faces many challenges, with the high cost of separators being particularly prominent, becoming one of the main bottlenecks restricting the further promotion and application of MFCs. As one of the core components of an MFC, the performance of the separator directly affects the operating efficiency and stability of the entire system. As a physical barrier between the anode and cathode, the separator not only needs to possess low ion transfer resistance but also the ability to effectively maintain the matrix concentration difference and dissolved oxygen difference between the cathode and anode to ensure the normal operation and efficient power generation of the MFC.

[0004] Currently, the most commonly used separator is the ion exchange membrane, but its high cost and short lifespan undoubtedly increase the risks and difficulties of operation and maintenance, limiting the widespread application of MFC technology. Furthermore, ion exchange membranes also have other problems, such as susceptibility to fouling and limited selective permeability, which further affect the performance and stability of MFC systems.

[0005] In conclusion, although MFC technology has shown great potential in wastewater treatment and energy recovery, issues related to separator cost, maintenance, lifespan, and reactor design remain unresolved. Therefore, developing separators with lower costs and superior performance is of great significance to improve the economics and practicality of MFC technology. Summary of the Invention

[0006] Therefore, one of the technical problems to be solved by the present invention is to provide a microbial fuel cell that is economical and has excellent performance.

[0007] The second technical problem to be solved by the present invention is to provide the application of the above-mentioned microbial fuel cell.

[0008] To solve the above-mentioned technical problems, the present invention provides a microbial fuel cell, including a reaction chamber, wherein a conductive dynamic membrane separator is provided in the reaction chamber, the conductive dynamic membrane separator divides the reaction chamber into a cathode chamber and an anode chamber, and the conductive dynamic membrane separator is electrically connected to the cathode chamber or the anode chamber;

[0009] The conductive dynamic membrane separator comprises, from the inside out, a dynamic membrane, a metal current collector, and an oxygen barrier layer. The dynamic membrane includes a frame material and a base membrane. The frame material supports the base membrane, and the base membrane is made of a conductive porous material.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] 1. This invention uses a metal grid as its framework, providing both support and energy collection. The microbial separator design, based on a conductive porous material and encased in an oxygen-barrier layer (which can be made of materials such as fiberglass cloth (membrane) or other materials with oxygen-barrier functions), significantly improves effluent quality and oxygen barrier effect while reducing the manufacturing cost of the exchange membrane. Furthermore, this design can directly extract chemical energy from pollutants and convert it into electrical energy output, further reducing operating costs. More importantly, the fuel cell structure of this invention is compact, occupies a small area, and is easy to operate, making it ideal for modular and integrated reactor designs, demonstrating broad application potential in wastewater treatment and reclaimed water reuse.

[0012] 2. This invention, by electrically connecting the conductive dynamic membrane separator to the cathode or anode chamber, not only effectively expands the electrode area but also shortens the distance between the electrodes, thereby enhancing the electric field interaction and mass transfer efficiency between the anode and cathode chambers. This design promotes the adsorption and deposition of inoculum microorganisms on the cathode chamber and separator surface, thus significantly improving the power generation performance of the microbial fuel cell.

[0013] 3. The electroactive microorganisms loaded in the separator can further enhance the transformation and removal of pollutants as wastewater passes through the separator interface, thereby effectively improving water quality. At the same time, the loaded aerobic bacteria can consume oxides at the separator interface, further playing a role in isolating oxidation and reducing the adverse effects of aeration on microorganisms.

[0014] In summary, the microbial fuel cell solution of the present invention is low in cost and has superior performance, demonstrating good economic efficiency and practicality.

[0015] In one embodiment of the invention, a variable external resistor is electrically connected between the cathode chamber and the anode chamber.

[0016] In one embodiment of the present invention, the microbial fuel cell further includes a circuit unit, and carbon brushes are respectively provided in the cathode chamber and the anode chamber, and the carbon brushes are electrically connected to the circuit unit.

[0017] In one embodiment of the present invention, the microbial fuel cell further includes a water inlet unit and a water outlet unit, which are respectively connected to the reaction chamber.

[0018] In one embodiment of the invention, the water inlet unit is used to supply wastewater to the reaction chamber. Supplying wastewater to the reaction chamber via the water inlet unit facilitates wastewater regeneration.

[0019] In one embodiment of the present invention, the water inlet unit includes a water inlet pipe and a water inlet pump, and the wastewater enters the reaction chamber under the action of the water inlet pump.

[0020] In one embodiment of the present invention, the water inlet unit is connected to the anode chamber, and the water outlet unit is connected to the cathode chamber.

[0021] When wastewater enters the anode chamber, the pollutants in the water are first oxidized by anode microorganisms. At the same time, the electrons generated by oxidation are transferred from the external circuit to the cathode chamber by electroactive microorganisms. As the water flows through the separator and the cathode chamber, the relevant microorganisms further treat the pollutants that have not been completely degraded. Meanwhile, the separator can play a dual role of filtering and intercepting and preventing the transfer of oxidation from the cathode chamber to the anode chamber, which can better ensure the wastewater treatment effect.

[0022] In one embodiment of the present invention, the microbial fuel cell further includes an aeration unit, at least a portion of which is located in the cathode chamber.

[0023] In one embodiment of the present invention, the aeration unit includes an aeration bar located at the bottom of the cathode chamber.

[0024] In one embodiment of the present invention, the conductive porous material includes at least one selected from carbon cloth, carbon felt, titanium foam, and nickel foam. The substrate membrane can be prepared using inexpensive conductive porous materials, further reducing manufacturing costs and improving the economics of fuel cells.

[0025] In one embodiment of the present invention, the mesh size of the conductive porous material is 100 to 400 mesh.

[0026] In one embodiment of the present invention, the material of the metal current collector network includes at least one of stainless steel mesh and titanium mesh.

[0027] In one embodiment of the present invention, the mesh size of the metal current collector is 6 to 100 mesh.

[0028] The present invention also provides the application of the above-mentioned microbial fuel cell in wastewater treatment.

[0029] The present invention also provides a wastewater treatment system, the wastewater treatment system comprising a wastewater treatment device, the wastewater treatment device comprising at least one of the above-described microbial fuel cells.

[0030] In one embodiment of the present invention, the wastewater treatment system further includes an energy recovery device, which is electrically connected to the wastewater treatment device.

[0031] In one embodiment of the present invention, the wastewater treatment system further includes a water recovery device, which is connected to the effluent unit in the wastewater treatment device.

[0032] In one embodiment of the present invention, the wastewater treatment device includes two or more of the above-mentioned microbial fuel cells, which are connected in parallel or in series.

[0033] Multiple microbial fuel cells can work together to achieve better wastewater treatment and resource recovery results. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the microbial fuel cell in Embodiments 1-2 of the present invention.

[0035] Figure 2 This is a schematic diagram of the conductive dynamic membrane separator in Embodiments 1-2 of the present invention.

[0036] Figure 3 These are the Vt curves of the microbial fuel cells during stable operation in Examples 1-2 and the comparative examples of the present invention.

[0037] Figure 4 It refers to the COD concentration in the cathode and anode chambers of the microbial fuel cell under a certain test condition during stable operation in Examples 1-2 and the comparative examples of the present invention.

[0038] Explanation of reference numerals in the attached diagram: 1-1 Inlet tank; 1-2 Inlet pump; 1-3 Inlet; 1-4 Outlet; 2-1 Voltage acquisition card; 2-2 Resistor; 2-3 Anode carbon brush; 2-4 Cathode carbon brush; 2-5 Conductive dynamic membrane separator; 3-1 Reaction chamber shell; 3-2 Aeration strip; 3-3 Outlet tank; 3-4 Aeration pump; 4-1 Fiberglass cloth; 4-2 Metal collector grid; 4-3 Base membrane; 4-4 Frame material. Detailed Implementation

[0039] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0040] Example 1

[0041] This example provides a microbial fuel cell with a conductive dynamic membrane separator. Its structural schematic diagram is shown below. Figure 1 As shown, the device consists of an inlet unit, a reaction unit, a conductive dynamic membrane separator, an outlet unit, an aeration unit, and a circuit unit.

[0042] The reaction unit and part of the aeration unit are located inside the reaction chamber shell 3-1. The conductive dynamic membrane separator 2-5 divides the internal space of the reaction chamber shell 3-1 into a cathode chamber and an anode chamber.

[0043] The water inlet unit consists of a water pipe, a water inlet pool 1-1, a water inlet pump 1-2, and a water inlet 1-3. The water inlet 1-3 is connected to the lower part of the anode chamber, and the water inlet pump 1-2 pumps the sewage in the water inlet pool 1-1 into the anode chamber through the water inlet 1-3.

[0044] The water outlet unit consists of a water pipe, an outlet pool 3-3, and an outlet 1-4. The outlet 1-4 is connected to the upper part of the cathode chamber, and the treated water flows into the outlet pool 3-3 through the outlet 1-4.

[0045] like Figure 2 As shown, the conductive dynamic membrane separator 2-5 uses an inexpensive conductive porous material (carbon felt) to make the base membrane 4-3. The base membrane 4-3 is supported by a frame material 4-4 and located inside the separator. A metal current collector 4-2 is installed outside the base membrane 4-3, and then wrapped with fiberglass cloth 4-1. The metal current collector 4-2 (made of stainless steel) serves as both a supporting material and a current collector for the separator. The metal current collector 4-2 is electrically connected to the cathode carbon brush 2-4 via wires.

[0046] The aeration unit consists of an aeration pump 3-4 and an aeration strip 3-2. The aeration strip 3-2 is placed below the carbon brush in the cathode chamber, and the aeration pump 3-4 pumps air into the cathode chamber through the aeration strip 3-2.

[0047] The circuit unit consists of wires, resistor 2-2, cathode carbon brush 2-4, and anode carbon brush 2-3. Resistor 2-2 is electrically connected to cathode carbon brush 2-4 and anode carbon brush 2-3 respectively via wires. One end of anode carbon brush 2-3 extends into the anode chamber and the other end is electrically connected to one end of resistor 2-2. One end of cathode carbon brush 2-4 extends into the cathode chamber and the other end is electrically connected to one end of resistor 2-2.

[0048] In addition, a voltage acquisition card 2-1 was connected to the circuit unit for easy observation, which records the voltage-time curves on both sides of resistor 2-2 in real time.

[0049] The reaction chamber is inoculated with effluent from a microbial fuel cell that has been operating stably for more than two years; the influent enters the reaction chamber shell 3-1 under the action of the influent pump 1-2, and flows sequentially through the anode chamber and the cathode chamber; an external voltage is applied to acclimate the electroactive microorganisms at the anode, and the current magnitude is used as an indicator of acclimatization maturity, which is monitored by a current acquisition system; after the electroactive microorganisms at the anode have been acclimatized, the external voltage is removed, and an external resistor 2-2 is applied between the anode and cathode to aerate and acclimatize the autotrophic microorganisms at the cathode, and the power output is used as an indicator of acclimatization maturity, which is monitored by a voltage acquisition card 2-1.

[0050] Example 2

[0051] This example provides a microbial fuel cell with a conductive dynamic membrane separator. Its only difference from Example 1 is that the metal current collector is electrically connected to the anode carbon brush.

[0052] Comparative Example

[0053] This example provides a microbial fuel cell with a conductive dynamic membrane separator. Its only difference from Example 1 is that the metal current collector is not electrically connected to the cathode or anode carbon brush.

[0054] Using the microbial fuel cell in the comparative example above, MFC effluent from the same source that has been operating stably for more than two years was used as the inoculum source. The separator was connected to the cathode in the circuit by wires. An external voltage of 1.0V was applied to acclimate the electroactive microorganisms at the anode. After the anode current stabilized, the external voltage was removed. An external resistor of 10Ω was connected between the anode and cathode and aeration was added to the cathode chamber. A voltage acquisition card was used to record the voltage change curve of the resistor over time.

[0055] The results of Examples 1-2 and the comparative examples are as follows: Figure 3 As shown in the figure, combining the separator and cathode in Example 1 significantly increases the voltage generated by the device, with a maximum voltage of 0.291V, far exceeding the 0.161V of the comparative example. In Example 3, combining the separator and anode further increases the voltage generated by the device, with a maximum voltage of 0.176V, also higher than the 0.161V of the comparative example.

[0056] Furthermore, the performance of the microbial fuel cell in treating organic matter was investigated by adding sodium acetate to the continuous feed water, and the COD concentration in the anode and cathode chambers was measured using a COD analyzer. The system operated continuously for 35 days, with measurements taken every 3 days. The results are as follows: Figure 4As shown, the COD concentration of the influent was 1045±32 mg / L. In Example 1, connecting the separator to the cathode can significantly reduce the COD concentration in the anode chamber of the device to as low as 56±8 mg / L, which is much lower than the 111±18 mg / L of the comparative example. After the influent passes through the separator from the anode chamber into the cathode chamber, the COD is further reduced. In Example 1, the COD of the cathode chamber is reduced to 41±1 mg / L, which is lower than the 56±8 mg / L of the comparative example.

[0057] In Example 2, connecting the separator to the anode can reduce the COD concentration in the anode chamber of the device to as low as 83±8 mg / L, which is lower than the 111±18 mg / L of the comparative example. After the influent passes through the separator from the anode chamber into the cathode chamber, the COD is further reduced. The COD in the cathode chamber of the device in Example 2 is reduced to 46±2 mg / L, which is lower than the 56±8 mg / L of the comparative example.

[0058] In summary, in the microbial fuel cell of this embodiment, wastewater flows into the anode chamber under the action of the influent pump, then passes through the electroactive microbial separator and enters the cathode chamber, where aeration occurs. Upon entering the anode chamber, the electroactive microorganisms on the anode carbon brush surface degrade organic pollutants and transfer electrons to the anode. These electrons are then transferred to the cathode chamber via the circuit, where they undergo a reduction reaction with electron acceptors such as oxygen. Incompletely degraded pollutants are further degraded and removed by relevant microorganisms as they flow through the conductive dynamic membrane separator and the cathode chamber. This invention connects the conductive dynamic membrane separator to the cathode or anode in the circuit unit via wires, expanding the electrode working area while shortening the distance between electrodes, thus improving the performance of the microbial fuel cell. Furthermore, microorganisms in the water can be adsorbed and deposited on the separator surface under the interception of the porous substrate and electrostatic action, forming a microbial separator. This separator consumes oxygen while degrading organic matter, thereby better preventing oxygen transfer from the cathode chamber to the anode chamber and enhancing the wastewater treatment effect.

[0059] This invention cleverly utilizes low-cost porous materials as a substrate to achieve dynamic membrane technology through the formation of a biofilm, significantly reducing the manufacturing cost of the exchange membrane. This dynamic membrane not only allows for free ion migration but also features high membrane flux and low resistance, ensuring smooth passage of wastewater and molecules, effectively reducing transmembrane pH differences, and improving the overall operating efficiency of the MFC. Due to the advantages of high membrane flux, low resistance, and self-sustainability, the fuel cell solution of this invention demonstrates significant market potential and application prospects in pilot-scale MFC applications.

[0060] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A microbial fuel cell, characterized by: The microbial fuel cell comprises a reaction chamber, wherein an electrically conductive dynamic membrane separator is arranged in the reaction chamber, the electrically conductive dynamic membrane separator separates the reaction chamber into a cathode chamber and an anode chamber, and the electrically conductive dynamic membrane separator is electrically connected with the cathode chamber or the anode chamber; The electrically conductive dynamic membrane separator comprises, from inside to outside, a dynamic membrane, a metal current collecting grid and an oxygen barrier layer, the dynamic membrane comprises a frame material and a base membrane, the frame material is used for supporting the base membrane, and the base membrane is made of an electrically conductive porous material; The microbial fuel cell further comprises a circuit unit, and carbon brushes are arranged in the cathode chamber and the anode chamber respectively, and the carbon brushes are electrically connected with the circuit unit respectively. The metal current collecting grid is connected with a cathode carbon brush in the cathode chamber or an anode carbon brush in the anode chamber through a wire.

2. The microbial fuel cell of claim 1, wherein: The microbial fuel cell further comprises a water inlet unit and a water outlet unit, the water inlet unit is communicated with the anode chamber, and the water outlet unit is communicated with the cathode chamber.

3. The microbial fuel cell of claim 1, wherein: The microbial fuel cell further comprises an aeration unit, and at least a part of the aeration unit is located in the cathode chamber.

4. The microbial fuel cell according to any one of claims 1 to 3, wherein: The electrically conductive porous material comprises at least one of carbon cloth, carbon felt, titanium foam and nickel foam.

5. The microbial fuel cell according to any one of claims 1 to 3, wherein: The electrically conductive porous material has a mesh number of 100-400.

6. The microbial fuel cell according to any one of claims 1 to 3, wherein: The metal current collecting grid is made of at least one of stainless steel mesh and titanium mesh.

7. The microbial fuel cell according to any one of claims 1 to 3, wherein: The metal current collecting grid has a mesh number of 6-100.

8. Application of the microbial fuel cell according to any one of claims 1-7 in sewage treatment.

9. A sewage treatment system characterised by: The sewage treatment system comprises a sewage treatment device, and the sewage treatment device comprises at least one microbial fuel cell according to any one of claims 1-7.

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