Microbial fuel cell with conductive dynamic membrane separator and application thereof

Abstract

The invention discloses a microbial fuel cell with a conductive dynamic membrane separator and application of the microbial fuel cell. 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 sequentially comprises a dynamic membrane, a metal power collection net and an oxygen isolation layer from inside to outside, the dynamic membrane comprises a frame material and a basement membrane, the frame material is used for supporting the basement membrane, and the basement membrane is made of a conductive porous material. The metal power collection net serves as a framework, the supporting function is achieved, and the power collection function is achieved. The ingenious design of the fuel cell structure in the scheme of the invention not only significantly improves the effluent quality and the oxygen isolation effect, but also reduces the manufacturing cost of the exchange membrane, and shows wide application potential in the fields of sewage treatment and reclaimed water reuse.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment and resource recovery, and in particular to a microbial fuel cell with a conductive dynamic membrane separator and application thereof. Background Art

[0002] As the cornerstone of maintaining human survival and promoting social development, the importance of water resources protection and sustainable utilization is self-evident. Therefore, humans must attach great importance to and devote themselves to the development of efficient sewage treatment and regeneration technologies, which is not only an urgent need to alleviate environmental pressure and protect ecological balance, but also an important way to achieve sustainable development.

[0003] Microbial fuel cells (MFCs) can use organic pollutants as anode fuels, convert biomass energy into electrical energy through the catalytic action of microorganisms, realize the organic combination of sewage treatment and electricity production, and provide a new idea for the resource utilization of sewage. However, in the actual application process, MFC technology still faces many challenges, among which the high cost of separators is particularly prominent, becoming one of the main bottlenecks restricting the further promotion and application of MFC. As one of the core components of MFC, the performance of the separator is directly related to the operating efficiency and stability of the entire system. As a physical barrier between the anode and the cathode, the separator not only needs to have the characteristics of low ion transfer resistance, but also needs to have the ability to effectively maintain the matrix concentration difference and dissolved oxygen difference between the cathode and the anode to ensure the normal operation and efficient power generation of MFC.

[0004] At present, the most commonly used separator is the ion exchange membrane, but its high cost and short service life undoubtedly increase the risk and difficulty of operation and maintenance, limiting the widespread application of MFC technology. In addition, ion exchange membranes also have some other problems, such as susceptibility to contamination and limited selective permeability, which further affects the performance and stability of the MFC system.

[0005] In summary, although MFC technology has shown great potential in wastewater treatment and energy recovery, the problems of separators in terms of cost, maintenance, service life and reactor design have not been completely solved. Therefore, it is of great significance to develop separators with lower cost and better performance to improve the economy 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 with high economy and 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] In order to solve the above technical problems, the present invention provides a microbial fuel cell, comprising a reaction chamber, wherein a conductive dynamic membrane separator is arranged in the reaction chamber, wherein the conductive dynamic membrane separator separates 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 includes a dynamic membrane, a metal collector grid and an oxygen isolation layer from the inside to the outside. The dynamic membrane includes a frame material and a base membrane. The frame material is used to support the base membrane. The base membrane is made of a conductive porous material.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. The present invention uses a metal collector grid as a skeleton, which not only plays a supporting role but also has a collector function. The design of a microbial separator with a conductive porous material as a substrate and an oxygen-isolating layer wrapped on the outside (which can be made of materials such as glass fiber cloth (membrane), or other materials with oxygen-isolating function) not only significantly improves the effluent water quality and oxygen-isolating effect, but also reduces the production cost of the exchange membrane. In addition, the design can directly extract chemical energy from pollutants and convert it into electrical energy output, further reducing operating costs. It is worth mentioning that the fuel cell of the present invention has a compact structure, small footprint, and easy operation. It is very suitable for modular and integrated reactor design, and shows broad application potential in the fields of sewage treatment and reclaimed water reuse.

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

[0013] 3. The electroactive microorganisms loaded in the separator can further enhance the ability to transform and remove pollutants when the sewage passes through the separator interface, thereby effectively improving the water quality. At the same time, the loaded aerobic bacteria can consume the oxides on the separator interface, further play the role of isolating oxidation, and reduce the adverse effects of aeration on microorganisms.

[0014] In summary, the microbial fuel cell solution of the present invention has low cost and superior performance, showing good economy and practicability.

[0015] In one embodiment of the present 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 comprises a circuit unit, and carbon brushes are respectively arranged in the cathode chamber and the anode chamber, and the carbon brushes are respectively electrically connected to the circuit unit.

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

[0018] In one embodiment of the present invention, the water inlet unit is used to provide sewage to the reaction chamber. The sewage is provided to the reaction chamber through the water inlet unit to facilitate sewage 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 waste water 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 communicated with the anode chamber, and the water outlet unit is communicated with the cathode chamber.

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

[0022] In one embodiment of the present invention, the microbial fuel cell further comprises 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 comprises an aeration strip, and the aeration strip is located at the bottom of the cathode chamber.

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

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

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

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

[0028] The present invention also provides application of the microbial fuel cell in sewage treatment.

[0029] The present invention also provides a sewage treatment system, which includes a sewage treatment device, and the sewage treatment device includes at least one of the above-mentioned microbial fuel cells.

[0030] In one embodiment of the present invention, the sewage treatment system further comprises an electric energy recovery device, and the electric energy recovery device is electrically connected to the sewage treatment device.

[0031] In one embodiment of the present invention, the sewage treatment system further comprises a water recovery device, and the water recovery device is connected to a water outlet unit in the sewage treatment device.

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

[0033] Multiple microbial fuel cells can work together to achieve better sewage treatment and resource utilization effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the microbial fuel cell in Examples 1 and 2 of the present invention.

[0035] Figure 2 It is a schematic diagram of the structure of the conductive dynamic membrane separator in Examples 1 and 2 of the present invention.

[0036] Figure 3 This is the Vt curve of the microbial fuel cell in Examples 1 to 2 of the present invention and the comparative example when it is in stable operation.

[0037] Figure 4 It is the COD concentration in the cathode chamber and the anode chamber when the microbial fuel cell in Examples 1 to 2 of the present invention and the comparative example is running stably under a certain test condition.

[0038] Explanation of the reference numerals: 1-1 water inlet tank; 1-2 water inlet pump; 1-3 water inlet; 1-4 water 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 water outlet tank; 3-4 aeration pump; 4-1 glass fiber cloth; 4-2 metal collector grid; 4-3 base membrane; 4-4 frame material. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it, 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. Figure 1 As shown, the device consists of a water inlet unit, a reaction unit, a conductive dynamic membrane separator, a water outlet unit, an aeration unit and a circuit unit.

[0042] The reaction unit and part of the aeration unit are located in 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 is composed of a water pipe, a water inlet tank 1-1, a water inlet pump 1-2 and a water inlet 1-3, wherein 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 tank 1-1 into the anode chamber through the water inlet 1-3.

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

[0045] like Figure 2 As shown, the conductive dynamic membrane separator 2-5 is made of cheap conductive porous material (carbon felt) to form a base membrane 4-3, which is supported by a frame material 4-4 and located inside the separator. A metal collector grid 4-2 is arranged outside the base membrane 4-3, and then wrapped with a glass fiber cloth 4-1. The metal collector grid 4-2 (stainless steel material) serves as a supporting material and a collector for the separator. The metal collector grid 4-2 is electrically connected to the cathode carbon brush 2-4 through a wire.

[0046] The aeration unit is composed 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. The aeration pump 3-4 pumps air into the cathode chamber through the aeration strip 3-2.

[0047] The circuit unit is composed of a wire, a resistor 2-2, a cathode carbon brush 2-4 and an anode carbon brush 2-3. The resistor 2-2 is electrically connected to the cathode carbon brush 2-4 and the anode carbon brush 2-3 through wires. One end of the anode carbon brush 2-3 extends into the anode chamber and the other end is electrically connected to one end of the resistor 2-2. One end of the cathode carbon brush 2-4 extends into the cathode chamber and the other end is electrically connected to one end of the resistor 2-2.

[0048] In addition, for the convenience of observation, a voltage acquisition card 2-1 is also connected to the circuit unit to record the voltage-time curve on both sides of the resistor 2-2 in real time.

[0049] The reaction chamber is inoculated with the outlet water of a microbial fuel cell that has been running stably for more than two years; the inlet water enters the reaction chamber shell 3-1 under the action of the inlet pump 1-2, and flows through the anode chamber and the cathode chamber in sequence; an external voltage is added to domesticate the electroactive microorganisms at the anode, and the current size is used as the domestication maturity indicator, which is monitored by the current acquisition system; after the domestication of the anode electroactive microorganisms is completed, the external voltage is removed, and a resistor 2-2 is added between the anode and the cathode, and aeration is performed in the cathode chamber to domesticate the cathode autotrophic microorganisms, and the power production is used as the domestication maturity indicator, which is monitored by the voltage acquisition card 2-1.

[0050] Example 2

[0051] This example provides a microbial fuel cell with a conductive dynamic membrane separator, which differs from Example 1 only in that the metal collector grid 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. The only difference between this example and Example 1 is that the metal collector grid is not electrically connected to the cathode or anode carbon brushes.

[0054] Using the microbial fuel cell in the comparative example of the above embodiment, the effluent of the MFC that has been stably operated for more than two years from the same source is used as the inoculation source, the separator is connected to the cathode in the circuit through a wire, and an external voltage of 1.0V is applied to acclimate the electroactive microorganisms at the anode. After the anode current is stable, the external voltage is removed, an external resistor of 10Ω is connected between the anode and the cathode, and aeration is added to the cathode chamber. A voltage acquisition card is used to record the curve of the voltage generated on the resistor over time.

[0055] The results of Examples 1 to 2 and Comparative Examples are as follows Figure 3 As shown in the figure, it can be seen that in Example 1, the separator and the cathode can significantly increase the voltage generated by the device, and the maximum voltage is 0.291V, which is much higher than 0.161V in the comparative example. In Example 3, the separator and the anode can increase the voltage generated by the device, and the maximum voltage is 0.176V, which is also higher than 0.161V in 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 flow influent, and the COD concentration in the anode and cathode chambers was measured by a COD meter. The operation was continued for 35 days, with measurements taken every 3 days. Figure 4As shown, the COD concentration of the influent is 1045±32 mg / L. In Example 1, connecting the separator to the cathode can significantly reduce the COD concentration of the anode chamber in the device to 56±8 mg / L, which is much lower than 111±18 mg / L in 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 of the cathode chamber in Example 1 is reduced to 41±1 mg / L, which is lower than 56±8 mg / L in 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 83±8 mg / L, which is lower than 111±18 mg / L in the comparative example; the COD of the influent is further reduced after passing through the separator from the anode chamber into the cathode chamber, and the COD of the cathode chamber in the device of Example 2 is reduced to 46±2 mg / L, which is lower than 56±8 mg / L in the comparative example.

[0058] In summary, in the microbial fuel cell of the embodiment of the present invention, sewage flows into the anode chamber under the action of the water inlet pump, and then passes through the electroactive microbial separator into the cathode chamber, and aeration is performed in the cathode chamber; when sewage enters the anode chamber, the electroactive microorganisms on the surface of the anode carbon brush degrade the organic pollutants and transfer electrons to the anode, and the electrons are transferred to the cathode chamber through the circuit, and a reduction reaction occurs with electron acceptors such as oxygen in the cathode chamber; pollutants that are not completely degraded are further deeply degraded and removed by relevant microorganisms when they flow through the conductive dynamic membrane separator and the cathode chamber. The present invention connects the conductive dynamic membrane separator to the cathode or anode in the circuit unit through a wire, while expanding the working area of ​​the electrode, shortening the distance between the electrodes, and realizing the improvement of the performance of the microbial fuel cell; in addition, the microorganisms in the water body can be adsorbed and deposited on the surface of the separator under the interception of the porous substrate in the separator and the action of electrostatics, forming a microbial separator, consuming oxygen while degrading organic matter, thereby better isolating the transfer of oxygen in the cathode chamber to the anode chamber, and enhancing the sewage treatment effect.

[0059] The embodiment of the present invention cleverly utilizes low-cost porous materials as a substrate, realizes dynamic membrane technology through the formation of biofilm, and significantly reduces the manufacturing cost of the exchange membrane. This dynamic membrane not only allows ions to migrate freely, but also has the characteristics of high membrane flux and low resistance, ensuring the smooth passage of sewage and molecules, effectively reducing the transmembrane pH difference, and improving the overall operating efficiency of the MFC. Since the dynamic membrane has the advantages of high membrane flux, low resistance and self-sustainability, the fuel cell of the embodiment of the present invention has shown huge market potential and application prospects in MFC applications at the pilot level.

[0060] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A microbial fuel cell, characterized in that: It comprises a reaction chamber, wherein a conductive dynamic membrane separator is arranged in the reaction chamber, the conductive dynamic membrane separator separates 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; The conductive dynamic membrane separator comprises a dynamic membrane, a metal collector grid and an oxygen isolation layer from the inside to the outside. The dynamic membrane comprises a frame material and a base membrane. The frame material is used to support the base membrane. The base membrane is made of a conductive porous material.

2. The microbial fuel cell according to claim 1, characterized in that: The microbial fuel cell further comprises a circuit unit. The cathode chamber and the anode chamber are respectively provided with carbon brushes, and the carbon brushes are respectively electrically connected to the circuit unit.

3. The microbial fuel cell according to claim 1, characterized in that: The microbial fuel cell further comprises a water inlet unit and a water outlet unit, wherein the water inlet unit is communicated with the anode chamber, and the water outlet unit is communicated with the cathode chamber.

4. The microbial fuel cell according to claim 1, characterized in that: The microbial fuel cell further comprises an aeration unit, at least a portion of which is located in the cathode chamber.

5. The microbial fuel cell according to any one of claims 1 to 4, characterized in that: The conductive porous material includes at least one of carbon cloth, carbon felt, titanium foam and nickel foam.

6. The microbial fuel cell according to any one of claims 1 to 4, characterized in that: The mesh number of the conductive porous material is 100 to 400 meshes.

7. The microbial fuel cell according to any one of claims 1 to 4, characterized in that: The material of the metal collector grid includes at least one of a stainless steel mesh and a titanium mesh.

8. The microbial fuel cell according to any one of claims 1 to 4, characterized in that: The mesh number of the metal collector grid is 6 to 100 meshes.

9. Use of the microbial fuel cell according to any one of claims 1 to 8 in sewage treatment.

10. A sewage treatment system, characterized in that: 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 to 8.

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