Lignin-based biomass charcoal electrode performance research
The preparation of functionalized lignin-based biomass carbon electrodes through flash joule thermal technology solves the problems of high cost and large energy loss in traditional anode materials, and achieves efficient biomass waste utilization and high-yield electrical performance of microbial fuel cells.
Patent Information
- Application Number
- CN202510486949.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2025-07-29
AI Technical Summary
The anode materials of existing microbial fuel cells are costly, have poor biocompatibility, and have low capacitance. The traditional carbonization method has large energy loss and cumbersome operation, which limits its application in the fields of sewage treatment and energy.
Functional lignin-based biomass carbon electrodes were prepared by flash joule heat technology in one step. An anode material with high biocompatibility and excellent capacitance performance was prepared through pretreatment of Ganoderma lucidum bran, hydrothermal reaction, flash joule heat treatment and cobalt iron doping.
It realizes efficient recycling and utilization of biomass waste, improves the extracellular electron transfer rate and the power production, stability and capacitance performance of microbial fuel cells, and improves pollutant removal efficiency and electricity output.
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Figure CN120389053A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of microbial fuel cells, and relates to the preparation and performance research of a functionalized lignin-based biomass carbon electrode prepared by flash Joule heating. Background Art
[0002] Microbial fuel cells (MFCs) are devices that utilize the metabolic action of microorganisms to remove pollutants while generating electrical energy. They play an important role in the fields of sewage treatment and alleviating energy crises. The power generation and pollutant removal efficiency of MFCs are synergistically affected by various factors. Its core mechanism involves microbial metabolism, electron transfer, reactor design, and operating conditions, etc. Among them, the anode, as the place where bacteria inhabit, its surface properties directly affect the metabolic state of bacteria and the power generation performance of MFCs. Traditional anode materials have few contact sites, poor hydrophilicity, low capacitance, and high costs. Therefore, preparing an anode material with low cost, good biocompatibility, and high active sites may be a powerful means to break through the bottleneck of MFCs.
[0003] Bacterial residue is the remaining medium after cultivating edible fungi using biomass raw materials such as corncobs and soybean meal. Its main components are compounds such as lignin, crude protein, crude fiber, and crude fat. Due to the nitrogen fixation effect during the growth of edible fungi, this material has a high nitrogen content. Research shows that N doping can effectively promote the electron transfer between microorganisms and materials. Reports on directly using a tube furnace for carbonization are common. This method has high energy consumption, is cumbersome to operate, and goes against the original intention of our green chemistry. Flash Joule heating (FJH) is a method that utilizes the Joule heat effect of materials to raise their temperature to thousands of degrees Celsius in a very short time (seconds), and is used for the synthesis and functionalization of nanomaterials such as graphene and high-entropy alloys. Compared with traditional material preparation methods such as tube furnaces and solvothermal methods, this synthesis method has advantages such as short preparation time, simple operation, and low energy consumption. There is no report on using flash Joule heating to prepare and functionalize lignin-based biomass-derived carbon materials for the anode of MFCs. This synthesis method of biomass provides a new foothold for the large-scale application of MFCs, and also provides a new idea for the treatment and functionalization of waste lignin-based biomass materials. Summary of the Invention
[0004] Based on the above background, the present invention provides a method for rapidly preparing a functionalized lignin-based biomass carbon electrode, and studies its application in microbial fuel cells. The flash Joule heating technology is used to carbonize and functionalize lignin-based biomass materials in one step. This method quickly and efficiently completes the recycling of biomass waste and the preparation of the anode of microbial fuel cells, and its biocompatibility and capacitance performance effectively promote the extracellular electron transfer rate between the material and microorganisms.
[0005] The present invention is achieved through the following solutions: Using Ganoderma lucidum spent mushroom substrate as raw material, after washing with water and pickling with acid to remove soluble impurities. Using the solvothermal method to pre-carbonize it to obtain hydro-carbon, and then performing rapid carbonization and functionalization on it through a flash Joule heating device. Then, it is dropped onto carbon cloth (CC) and used as the anode of a microbial fuel cell.
[0006] The intrinsic electrochemical characterization shows that it has a high specific capacitance and good conductivity. The maximum voltage of the assembled battery reached 630 mV after running for 60 days. The chemical oxygen demand (COD) removal rate reached 94%. The biofilm thickness is thicker during long-term operation. The material proposed in the present invention can be used as the anode of a microbial fuel cell and improves its power generation and pollution removal efficiency.
[0007] The specific method includes:
[0008] S1. Preparation and pretreatment of Ganoderma lucidum spent mushroom substrate;
[0009] S2. Performing hydrothermal reaction on the treated Ganoderma lucidum spent mushroom substrate to pre-carbonize and obtain spent mushroom substrate hydro-carbon;
[0010] S3. Mixing the spent mushroom substrate hydro-carbon with cobalt-iron metal salts in equal proportion to obtain the precursor of flash Joule heating;
[0011] S4. Performing flash Joule heat treatment on the precursor to obtain cobalt-iron doped spent mushroom substrate graphene;
[0012] S5. Preparation of cobalt-iron doped graphene as anode material and assembly of a microbial fuel cell;
[0013] Preferably, the detailed content of the preparation and pretreatment of Ganoderma lucidum spent mushroom substrate in step S1 is: First, the Ganoderma lucidum spent mushroom substrate taken from a certain factory is crushed to 200 meshes using a crusher, then washed repeatedly 3 times with deionized water and hydrochloric acid (10 wt%) in sequence, and finally washed with deionized water until neutral to remove soluble impurities. It is dried in an oven at 60 °C for 12 h to obtain clean Ganoderma lucidum spent mushroom substrate. Then, it is ball-milled at a rate of 30 r / s for 30 min using a ball mill to obtain spent mushroom substrate powder.
[0014] Preferably, the detailed content of the hydrothermal carbonization process of the spent mushroom substrate in step S2 is: Adding 5 g of spent mushroom substrate powder to 50 ml of distilled water and ultrasonically treating it for 30 min at room temperature to obtain a uniform suspension. Then, the suspension is transferred to a 100 ml Teflon-lined stainless steel autoclave, and then the autoclave is placed in a homogeneous reactor and heated and reacted at 200 °C for 10 h. After the reaction, the product is repeatedly washed with deionized water, the precipitate is collected by centrifugation, and then dried in an oven at 60 °C for 12 h to obtain spent mushroom substrate hydro-carbon.
[0015] Preferably, the detailed content of the preparation of the flash Joule heat precursor in step S3 is as follows: Add fungal residue hydrochar and the same weight of metal salts (Co(NO3)2·6H2O and Fe(NO3)3·9H2O, with a metal element ratio of 1:1 mixture) into absolute ethanol, ultrasonically mix for 30 min to make them evenly mixed, then dry in a vacuum drying oven at 60 °C, and finally ball-mill and mix evenly the conductive carbon black and the dried solid in a mass ratio of 1:9 to obtain the precursor of flash Joule heat.
[0016] Preferably, the two metal salts in step S3 can be replaced with other two or more metal salts as needed. The particle size of the cobalt-iron nanoparticles is about 100 nm and they are directly loaded on the carbonized fungal residue.
[0017] Preferably, the detailed steps of the flash Joule heat treatment in step S4 are as follows: Take 100 mg of the fungal residue precursor in step S3 and add it into a quartz tube with an inner diameter of 6 mm, a thickness of 3 mm, and a length of 5 cm. Apply graphite rods at both ends to squeeze the reactants so as to control the initial resistance of the sample. Then connect the material to the two poles of the power supply, adjust the discharge voltage of the flash Joule heat to 150 V - 250 V, set the discharge time to 2 s, and the number of discharges to 2 times. Then use the discharge switch to achieve instantaneous discharge to obtain the flash graphene loaded with cobalt-iron.
[0018] Preferably, the detailed process of the preparation of the anode material in step S5 is to weigh 10 mg of the material in step S4 into a 5 mL centrifuge tube, and add 30 μL of Nafion solution, 325 μL of isopropanol, and 625 μL of deionized water, then ultrasonically mix for 10 min to make it evenly mixed. Take 52 μL of the above suspension and drop it on the surface of a 1 cm × 1 cm carbon cloth and dry it. Drop it on both sides to ensure that the loading amount reaches 0.5 mg / cm 2 . Finally, fix it with a titanium wire through a hole for use as the anode of a microbial fuel cell.
[0019] Preferably, the assembly of the microbial fuel cell in step S5 is as follows: The microbial fuel cell used in the invention is a two-chamber device, with a single chamber volume of 130 mL, made of glass, separated by a PEM in the middle. The anode is the material prepared in step S5, the cathode is a carbon brush. Initially, add 20 mL of sludge and 80 mL of anode solution to the anode, and add 100 mL of cathode solution to the cathode. The MFCs system is connected to an external resistor of 1000 Ω and cultured in an incubator at 35 °C. Use a data acquisition system to record the output voltage of the MFCs, record the data once a minute, and replace the cathode and anode solutions according to the output voltage value. When the voltage value is lower than 50 mV, replace the cathode and anode solutions.
[0020] Preferably, the spent mushroom substrate in the present invention is the residue of the culture medium after Ganoderma lucidum cultivation, and can be replaced with other lignin- and cellulose-based biomass materials, such as rice husks, soybean meal, straw, wood powder, etc.
[0021] Preferably, the morphological structure and physicochemical properties of the material can be regulated by optimizing the discharge voltage, pulse time, and discharge times of the flash Joule heating instrument to meet different requirements.
[0022] Preferably, when changing the cathode and anode solutions each time, the effluent and influent are retained for COD testing, digested with a COD detection kit at 150 °C for 2 hours, and then analyzed using a spectrophotometer.
[0023] Preferably, when the battery operates for 60 days, the anode material is taken out, rinsed with PBS buffer solution, then soaked and fixed in 4% paraformaldehyde at 4 °C for 4 h, followed by gradient dehydration with ethanol solutions of 30% - 100% concentration, air-dried at room temperature, sputter-coated with gold, and then the biofilm morphology is tested.
[0024] Compared with the existing methods for preparing anodes of microbial fuel cells, the present invention has the following advantages:
[0025] (1) The flash Joule heating equipment can synthesize the required materials within 2 s, accurately using all the energy for material preparation, thus greatly improving the energy utilization rate.
[0026] (2) As a biomass material, the spent mushroom substrate has a high nitrogen content, which is beneficial to improving the extracellular electron transfer rate; it has good biocompatibility, which is beneficial to bacterial adhesion and biofilm formation.
[0027] (3) After one-step functionalization, the capacitance performance of the material is improved, which is beneficial to timely storing the electrons generated by bacteria, improving the electron utilization rate, and finally enhancing the power generation performance of the microbial fuel cell.
[0028] (4) The CoFe nanoparticle / spent mushroom substrate carbon composite anode improves the power generation ability of the microbial fuel cell and its operation stability. The output voltage can still reach 620 mV at 60 days. Therefore, the CoFe nanoparticle / spent mushroom substrate carbon composite material prepared in this study is used as the anode of the microbial fuel cell to improve its power generation efficiency and stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Appendix Figure 1 is a graph of the color temperature - time change of the material during the flash Joule heating process
[0030] Appendix Figure 2 is the X-ray diffraction pattern of the CoFe nanoparticle / spent mushroom substrate carbon composite material (CoFe / MB);
[0031] AppendixFigure 3 Scanning electron microscope image of CoFe / MB
[0032] Attached Figure 4 High-magnification transmission electron microscope image of CoFe / MB, showing the lattice spacing of the material
[0033] Attached Figure 5 Intrinsic CV curve of the material
[0034] Attached Figure 6 Scanning electron microscope image of the biofilm of CoFe / MB on the 60th day of battery operation Attached Figure 7 Voltage-time curve of the microbial fuel cell operating for 60 days
[0035] Attached Figure 8 Charge-discharge curve of the microbial fuel cell
[0036] Attached Figure 9 CV curve of the material after the biofilm is mature Specific implementation mode
[0037] The present invention will be further described below in conjunction with specific embodiments, but it is not intended to limit the present invention
[0038] All materials involved in the embodiments of the present invention can be obtained from commercial channels
[0039] The present invention provides the preparation and application of CoFe / MB anode materials for microbial fuel cells by flash Joule heating. The specific embodiments are as follows
[0040] Example 1
[0041] The Ganoderma lucidum spent substrate was washed three times with deionized water and hydrochloric acid (10% wt) respectively, and finally washed with deionized water until neutral, then dried in an oven at 60 °C for 12 h to obtain clean spent substrate. Then, it was ball-milled for 30 min at a rate of 30 r / s using a ball mill to obtain spent substrate powder. 5 g of the spent substrate powder was added to 50 ml of distilled water and ultrasonicated for 30 min at room temperature to obtain a uniform suspension, and then the suspension was transferred to a 100 ml Teflon-lined stainless steel autoclave. Then, the autoclave was placed in a homogeneous reactor and heated at 200 °C for 10 h. After the reaction, the product was washed repeatedly with deionized water, centrifuged and collected, and finally dried in an oven at 60 °C for 12 h to obtain spent substrate hydrochar. The hydrochar and the same weight of metal salts (Co(NO3)2·6H2O and Fe(NO3)3·9H2O, mixed with a metal element ratio of 1:1) were added to anhydrous ethanol and ultrasonicated for 30 min, and then dried in a vacuum drying oven at 60 °C. Finally, 10 wt% of carbon black (as a conductive agent) was ball-milled and mixed with the dried solid to obtain the precursor of flash Joule. 100 mg of the precursor was added to a quartz tube with an inner diameter of 6 mm, a thickness of 3 mm, and a length of 5 cm. Graphite rods were applied at both ends to squeeze the reactants, and the initial resistance of each sample was kept consistent by adjusting the spring pressure at both ends of the reactor. The charging voltage of the capacitor was pre-adjusted to 100 V, and the discharge time was adjusted to 2 s. Then, the instantaneous discharge of the capacitor was realized by using a discharge switch. Five capacitors were charged to a voltage of 100 V and discharged once, and the product was ground evenly to obtain the CoFe nanoparticle / spent substrate hydrochar composite after flash evaporation.
[0042] Example 2
[0043] The Ganoderma lucidum residue was washed three times with deionized water and hydrochloric acid (10% wt) respectively, and finally washed with deionized water until neutral, then dried in an oven at 60 °C for 12 h to obtain clean residue. Then, it was ball-milled at a rate of 30 r / s for 30 min using a ball mill to obtain residue powder. 5 g of the residue powder was added to 50 ml of distilled water and ultrasonicated at room temperature for 30 min to obtain a homogeneous suspension, and then the suspension was transferred to a 100 ml Teflon-lined stainless steel autoclave. Then, the autoclave was placed in a homogeneous reactor and heated at 200 °C for 10 h. After the reaction, the product was washed repeatedly with deionized water, centrifuged and collected, and finally dried in an oven at 60 °C for 12 h to obtain residue hydrochar. The hydrochar and the same weight of metal salts (Co(NO3)2·6H2O and Fe(NO3)3·9H2O, mixed with a metal element ratio of 1:1) were added to anhydrous ethanol, ultrasonicated for 30 min, and then dried in a vacuum drying oven at 60 °C. Finally, 10 wt% of carbon black (as a conductive agent) was ball-milled and mixed with the dried solid to obtain a precursor for flash Joule. 100 mg of the precursor was added to a quartz tube with an inner diameter of 6 mm, a thickness of 3 mm, and a length of 5 cm. Graphite rods were applied at both ends to squeeze the reactants, and the initial resistance of each sample was kept consistent by adjusting the spring pressure at both ends of the reactor. The charging voltage of the capacitor was pre-adjusted to 100 V, and the discharge time was adjusted to 2 s. Then, the instantaneous discharge of the capacitor was realized by using a discharge switch. Five capacitors were charged to a voltage of 130 V and discharged once. The product was ground evenly to obtain the flash-vaporized CoFe nanoparticle / carbonized residue composite material.
[0044] Example 3
[0045] The Ganoderma lucidum spent substrate was washed three times each with deionized water and hydrochloric acid (10% wt), and finally washed with deionized water until neutral, and then dried in an oven at 60 °C for 12 h to obtain clean spent substrate. Then, it was ball-milled at a rate of 30 r / s for 30 min using a ball mill to obtain spent substrate powder. 5 g of the spent substrate powder was added to 50 ml of distilled water and sonicated at room temperature for 30 min to obtain a homogeneous suspension, and then the suspension was transferred to a 100 ml Teflon-lined stainless steel autoclave. Then, the autoclave was placed in a homogeneous reactor and heated at 200 °C for 10 h. After the reaction, the product was washed repeatedly with deionized water, centrifuged and collected, and finally dried in an oven at 60 °C for 12 h to obtain spent substrate hydrochar. The hydrochar and the same weight of metal salts (Co(NO3)2·6H2O and Fe(NO3)3·9H2O, mixed at a metal element ratio of 1:1) were added to anhydrous ethanol, sonicated for 30 min, and then dried in a vacuum drying oven at 60 °C. Finally, 10 wt% carbon black (as a conductive agent) was ball-milled and mixed with the dried solid to obtain a precursor for flash Joule. 100 mg of the precursor was added to a quartz tube with an inner diameter of 6 mm, a thickness of 3 mm, and a length of 5 cm. Graphite rods were applied at both ends to squeeze the reactants. By adjusting the spring pressure at both ends of the reactor, the initial resistance of each sample was kept consistent. The charging voltage of the capacitor was pre-adjusted to 150 V, and the discharge time was adjusted to 2 s. Then, the instantaneous discharge of the capacitor was realized using a discharge switch. Five capacitors were charged to a voltage of 150 V and discharged once. The product was ground evenly to obtain the CoFe nanoparticle / spent substrate hydrochar composite after flash evaporation.
[0046] Example 4
[0047] The Ganoderma lucidum residue was washed three times with deionized water and hydrochloric acid (10% wt) respectively, and finally washed with deionized water until neutral, then dried in an oven at 60 °C for 12 h to obtain clean residue. Then it was ball-milled at a rate of 30 r / s for 30 min using a ball mill to obtain residue powder. 5 g of the residue powder was added to 50 ml of distilled water and sonicated at room temperature for 30 min to obtain a uniform suspension, then the suspension was transferred to a 100 ml Teflon-lined stainless steel autoclave, and then the autoclave was placed in a homogeneous reactor and heated at 200 °C for 10 h. After the reaction, the product was washed repeatedly with deionized water, centrifuged and collected, and finally dried in an oven at 60 °C for 12 h to obtain residue hydrochar. The hydrochar and the same weight of metal salts (Mn(NO3)2·6H2O and Fe(NO3)3·9H2O, mixed with a metal element ratio of 1:1) were added to absolute ethanol, sonicated for 30 min, and then dried in a vacuum drying oven at 60 °C. Finally, 10 wt% of carbon black (as a conductive agent) was ball-milled and mixed with the dried solid to obtain a precursor for flash Joule. 100 mg of the precursor was added to a quartz tube with an inner diameter of 6 mm, a thickness of 3 mm and a length of 5 cm. Graphite rods were applied at both ends to extrude the reactants. By adjusting the spring pressure at both ends of the reactor, the initial resistance of each sample was kept consistent. The charging voltage of the capacitor was preset to 170 V and the discharge time was adjusted to 2 s. Then, the instantaneous discharge of the capacitor was realized by using a discharge switch. Five capacitors were charged to a voltage of 170 V and discharged once. The product was ground evenly to obtain the flash-annealed FeMn nanoparticles / carbonized residue composite material.
[0048] Example 5
[0049] The Ganoderma lucidum spent mushroom substrate was washed three times with deionized water and hydrochloric acid (10% wt) respectively, and finally washed with deionized water until neutral, then dried in an oven at 60 °C for 12 h to obtain clean spent mushroom substrate. Then, it was ball-milled at a rate of 30 r / s for 30 min using a ball mill to obtain spent mushroom substrate powder. 5 g of the spent mushroom substrate powder was added to 50 ml of distilled water and ultrasonicated at room temperature for 30 min to obtain a homogeneous suspension, and then the suspension was transferred to a 100 ml Teflon-lined stainless steel autoclave. Then, the autoclave was placed in a homogeneous reactor and heated at 200 °C for 10 h. After the reaction, the product was washed repeatedly with deionized water, centrifuged and collected, and finally dried in an oven at 60 °C for 12 h to obtain spent mushroom substrate hydrochar. The hydrochar and the same weight of metal salts (Co(NO3)2·6H2O and Mn(NO3)2·9H2O, mixed with a metal element ratio of 1:1) were added to absolute ethanol, ultrasonicated for 30 min, and then dried in a vacuum drying oven at 60 °C. Finally, 10 wt% of carbon black (as a conductive agent) was ball-milled and mixed with the dried solid to obtain a precursor for flash Joule. 100 mg of the precursor was added to a quartz tube with an inner diameter of 6 mm, a thickness of 3 mm, and a length of 5 cm. Graphite rods were applied at both ends to squeeze the reactants. By adjusting the spring pressure at both ends of the reactor, the initial resistance of each sample was kept consistent. The charging voltage of the capacitor was pre-adjusted to 190 V, and the discharge time was adjusted to 2 s. Then, the instantaneous discharge of the capacitor was realized by using a discharge switch. Five capacitors were charged to a voltage of 190 V and discharged once. The product was ground evenly to obtain the CoFe nanoparticle / spent mushroom substrate hydrochar composite after flash evaporation.
[0050] Example 6
[0051] The low-temperature soybean meal was washed three times each with deionized water and hydrochloric acid (10% wt), and finally washed with deionized water until neutral, and then dried in an oven at 60 °C for 12 h to obtain clean low-temperature soybean meal. Then, it was ball-milled for 30 min at a rate of 30 r / s using a ball mill to obtain soybean meal powder. 5 g of the soybean meal powder was added to 50 ml of distilled water and ultrasonicated for 30 min at room temperature to obtain a uniform suspension, and then the suspension was transferred to a 100 ml Teflon-lined stainless steel autoclave. Then, the autoclave was placed in a homogeneous reactor and heated at 200 °C for 10 h. After the reaction, the product was repeatedly washed with deionized water, centrifuged and collected, and finally dried in an oven at 60 °C for 12 h to obtain soybean meal hydrochar. The hydrochar and the same weight of metal salts (Co(NO3)2·6H2O and Fe(NO3)3·9H2O, mixed with a metal element ratio of 1:1) were added to absolute ethanol, ultrasonicated for 30 min, and then dried in a vacuum drying oven at 60 °C. Finally, 10 wt% of carbon black (as a conductive agent) was ball-milled and mixed with the dried solid to obtain a precursor for flash Joule. 100 mg of the precursor was added to a quartz tube with an inner diameter of 6 mm, a thickness of 3 mm, and a length of 5 cm. Graphite rods were applied at both ends to extrude the reactants. By adjusting the spring pressure at both ends of the reactor, the initial resistance of each sample was kept consistent. The charging voltage of the capacitor was preset to 210 V, and the discharge time was adjusted to 2 s. Then, the instantaneous discharge of the capacitor was realized using a discharge switch. Five capacitors were charged to a voltage of 210 V and discharged once. The product was ground evenly to obtain the CoFe nanoparticle / carbonized soybean meal composite after flash evaporation.
[0052] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.
Claims
1. Research on the performance of lignin-based biomass carbon electrodes, characterized in that Including: S1. Preparation and pretreatment of Ganoderma lucidum spent mushroom substrate; S2. Perform hydrothermal reaction on the treated Ganoderma lucidum spent mushroom substrate, and pre-carbonize to obtain spent mushroom substrate hydrochar; S3. Mix the spent mushroom substrate hydrochar and cobalt-iron metal salts in equal proportion to obtain the precursor of flash Joule heating; S4. Perform flash Joule heat treatment on the precursor to obtain cobalt-iron doped spent mushroom substrate graphene; S5. Preparation of cobalt-iron doped graphene as an anode material and assembly of a microbial fuel cell.
2. According to the study on the performance of lignin-based biomass carbon electrodes described in claim 1, characterized in that The detailed content of the preparation and pretreatment of Ganoderma lucidum spent mushroom substrate in step S1 is as follows: The Ganoderma lucidum spent mushroom substrate taken from a certain factory is first crushed to 200 meshes using a crusher, then washed repeatedly 3 times with deionized water and hydrochloric acid (10 wt%), and finally washed with deionized water until neutral to remove soluble impurities, and dried in a drying oven at 60 °C for 12 h to obtain clean Ganoderma lucidum spent mushroom substrate. Then use a ball mill to ball mill at a rate of 30 r / s for 30 min to obtain spent mushroom substrate powder.
3. According to the study on the performance of lignin-based biomass carbon electrodes described in claim 1, characterized in that The detailed content of the hydrothermal carbonization process of the spent mushroom substrate in step S2 is as follows: Add 5 g of spent mushroom substrate powder to 50 ml of distilled water and ultrasonically treat for 30 min at room temperature to obtain a uniform suspension. Then transfer the suspension to a 100 ml Teflon-lined stainless steel autoclave, and then place the autoclave in a homogeneous reactor and heat and react at 200 °C for 10 h. After the reaction, repeatedly wash the product with deionized water, centrifuge to collect the precipitate, and then dry in an oven at 60 °C for 12 h to obtain spent mushroom substrate hydrochar.
4. According to the study on the performance of lignin-based biomass carbon electrodes described in claim 1, characterized in that The detailed content of the preparation of the precursor of flash Joule heating in step S3 is as follows: Add the spent mushroom substrate hydrochar and the same weight of metal salts (Co(NO3)2·6H2O and Fe(NO3)3·9H2O, with a metal element ratio of 1:1 mixture) to anhydrous ethanol, ultrasonically treat for 30 min to mix them evenly, then dry in a vacuum drying oven at 60 °C, and finally ball mill and mix the conductive agent carbon black and the dried solid evenly at a mass ratio of 1:9 to obtain the precursor of flash Joule heating.
5. According to the study on the performance of lignin-based biomass carbon electrodes described in claim 4, characterized in that In step S3, the two metal salts can be replaced with other two or more metal salts according to needs. The particle size of the cobalt-iron nanoparticles is about 100 nm and is directly loaded on the carbonized spent mushroom substrate.
6. According to the study on the performance of lignin-based biomass carbon electrodes described in claim 2, characterized in that The spent mushroom substrate in step S1 belongs to the remaining substrate after Ganoderma lucidum cultivation and can be replaced with other biomass materials, such as rice husks, soybean meal, straw, wood powder, etc.
7. According to the study on the performance of lignin-based biomass carbon electrodes described in claim 1, characterized in that The microbial fuel cell used in step S5 is a two-chamber device. The volume of a single chamber is 130 mL, and the material is glass. The two chambers are separated by a PEM in the middle. The anode is the material prepared in step S5, and the cathode is a carbon brush. Initially, 20 mL of sludge and 80 mL of anolyte are added to the anode, and 100 mL of catholyte is added to the cathode. The MFCs system is connected to an external resistor of 1000 Ω and cultured in an incubator at 35 °C. A data acquisition system is used to record the output voltage of the MFCs, and data is recorded once per minute. The anolyte and catholyte are replaced according to the output voltage value. When the voltage value is lower than 50 mV, the anolyte and catholyte are replaced.