Microbial fuel cell carbon-based anode material, preparation method and application thereof

Abstract

The application discloses a microbial fuel cell carbon-based anode material and a preparation method thereof. In the application, mesoporous tungsten trioxide (m-WO3) with a large specific surface area is electrochemically deposited on a PDA / CF anode material to obtain an organic-inorganic doped composite anode, and a WO3-PDA / CF anode electrode is prepared, so that the structure and surface properties of the material are improved, and the conductivity and electrochemical activity are enhanced. Compared with the CF anode, the composite anode can accelerate the adsorption and growth rate of anode microorganisms, improve the anode microorganism loading capacity, activity and electron transfer rate, and finally improve the MFC power density output and wastewater treatment efficiency. Accordingly, the application also provides an application of the microbial fuel cell carbon-based anode material in a microbial fuel cell.

Description

Technical Field

[0001] This invention relates to the field of microbial fuel cell technology, and in particular to a carbon-based anode material for microbial fuel cells, its preparation method, and its application. Background Technology

[0002] Microbial fuel cells (MFCs) are an environmentally friendly novel bioenergy technology for water treatment, promising to solve energy shortages and water pollution problems, and have attracted widespread attention in recent years. This technology utilizes microorganisms as catalysts to degrade organic pollutants in wastewater and convert the chemical energy of the pollutants into electrical energy, potentially enabling wastewater treatment plants to achieve self-sufficiency in electricity and opening up a new avenue for wastewater treatment. Currently, the commercial application of microbial fuel cells remains challenging, primarily due to their low power density. To address this issue, optimization in areas such as MFC electrode fabrication has become a research hotspot. As the carrier for the growth, reproduction, and electron transfer of electrogenic microorganisms, the anode plays a crucial role in the performance of the MFC, directly affecting its power generation performance and degradation efficiency.

[0003] High-performance MFC anodes should possess characteristics such as large specific surface area, good biocompatibility, and high conductivity. Strategies such as surface modification of the anode material or optimization of the anode's structure or composition can effectively increase microbial loading and activity, improve electrode conductivity and electrochemical activity, thereby increasing the output power of the MFC.

[0004] The biggest obstacles to the widespread application of microbial fuel cells (MFCs) are the high cost of reactor construction, low electron transfer efficiency, and low power density. Among these, the slow extracellular electron transfer (EET) rate of microorganisms severely restricts the improvement of MFC power density, becoming a bottleneck limiting their application. As the site where electroactive bacterial communities decompose organic matter, metabolize, and generate electrons, the characteristics of the anode material have a significant impact on MFC performance and play an important role in promoting and maintaining microbial catalytic activity. Summary of the Invention

[0005] In order to solve the technical problems existing in the above-mentioned technologies, it is necessary to provide a method for preparing carbon-based anode materials for microbial fuel cells, so as to solve the technical problems of high cost, low electron transfer efficiency and low power density in constructing reactors.

[0006] A method for preparing a carbon-based anode material for a microbial fuel cell includes the following steps:

[0007] Step S1: Mix m-WO3 and PBS solution in the appropriate ratio and stir until homogeneous;

[0008] Step S2: Place the PDA / CF anode threaded with titanium wire into a mixed solution of m-WO3 and PBS, and purge with nitrogen gas;

[0009] Step S3: Connect the PDA / CF anode as the working electrode, the Pt electrode as the counter electrode, and the saturated calomel electrode as the reference electrode to the electrochemical workstation, and perform pre-deposition using the CV method;

[0010] Step S4: After pre-deposition, WO3-PDA / CF anode is obtained by electrodeposition to enhance conductivity and electrochemical activity.

[0011] Preferably, in step S1, magnetic stirring is used for stirring for 10 ± 1 min.

[0012] Preferably, in step S2, the nitrogen flow rate is 40±2 mL / min and the introduction time is 10±1 min.

[0013] Preferably, in step S3, the pre-deposition time is 10±1 min, the scan rate is 0.1 V / s, the working conditions are 0.9 V to -0.9 V, and 100 scan cycles are performed.

[0014] Preferably, in step S4, the voltage is maintained at -1.4 V, and electrodeposition is performed for 10 ± 1 min.

[0015] Preferably, in step S1, m-WO3 needs to be ground before use.

[0016] Preferably, m-WO3 is obtained through the following methods:

[0017] Mix phosphotungstic acid and ethanol in the appropriate proportions and stir until homogeneous;

[0018] KIT-6 was added to the mixed solution of phosphotungstic acid and ethanol during the stirring process, and the mixture was stirred magnetically at 55°C until dry to obtain a white powder.

[0019] The obtained white powder was heated to 500℃ within 240 min and calcined for 3 hours to obtain a light green powder;

[0020] After removing the light green powder with HF acid, stir for 1 hour and centrifuge.

[0021] The centrifuged material was washed three times each with distilled water and ethanol, and then dried in an oven at 60°C to obtain the m-WO3 product.

[0022] Preferably, the PDA / CF anode is obtained through the following methods:

[0023] Dissolve dopamine hydrochloride in H2SO4 solution and purge with nitrogen gas for 15 min;

[0024] The CF electrode was immersed in a mixed solution of dopamine hydrochloride and H2SO4. A saturated calomel electrode was used as the reference electrode and a platinum wire as the counter electrode. Ammonium persulfate initiator was added. The PDA / CF electrode was obtained by scanning 150 cycles at a rate of 100 mV / s and an operating condition of -0.1 v to 0.7 v using the CV method.

[0025] The present invention also provides a carbon-based anode material for microbial fuel cells, which is obtained by the preparation method of the carbon-based anode material for microbial fuel cells described above.

[0026] This invention also provides an application of carbon-based anode materials for microbial fuel cells in microbial fuel cells.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] This invention modifies a PDA / CF anode with large specific surface area mesoporous tungsten trioxide (m-WO3) to obtain an organic-inorganic doped composite anode. The MFC anode electrode is prepared using low-cost materials such as carbon felt, ferric sulfate, and dopamine hydrochloride. m-WO3 particles are prepared using a template method and electrochemically deposited onto the PDA / CF anode material to obtain a WO3-PDA / CF anode electrode. This improves the material's structure and surface properties, enhancing conductivity and electrochemical activity. Compared to the CF anode, the composite anode accelerates the adsorption and growth rate of anodic microorganisms, increases the anodic microbial loading, activity, and electron transport rate, ultimately improving the MFC power density output and wastewater treatment efficiency. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a comparison chart of the degradation of indole wastewater by WO3-PDA / CF anode and CF anode.

[0031] Figure 2 The graph shows the degradation curve of indole wastewater by WO3-PDA / CF anode circulation.

[0032] Figure 3 TEM images of m-WO3 and WO3-PDA / CF anodes.

[0033] Figure 4 SEM images of microbial growth on WO3-PDA / CF anode and CF anode. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention provides a method for preparing a carbon-based anode material for a microbial fuel cell, comprising the following steps:

[0036] Step S1: Mix m-WO3 and PBS solution in the appropriate ratio and stir until homogeneous;

[0037] Step S2: Place the PDA / CF anode threaded with titanium wire into a mixed solution of m-WO3 and PBS, and purge with nitrogen gas; under anaerobic conditions, the crosslinking effect between m-WO3 and PDA / CF materials is better.

[0038] Step S3: Connect the PDA / CF anode as the working electrode, the Pt electrode as the counter electrode, and the saturated calomel electrode as the reference electrode to the electrochemical workstation, and pre-deposit using the CV method; activate the electrode interface through dynamic potential cycling to inhibit nanoparticle aggregation.

[0039] Step S4: After pre-deposition, WO3-PDA / CF anodes are obtained by electrodeposition. By controlling the deposition potential, current, and deposition time, the thickness and particle size of WO3 are precisely controlled. Combined with the rough interface activated by the pre-deposition, WO3 will grow into a porous, nanoscale structure, significantly increasing the number of catalytic active sites.

[0040] The WO3-PDA / CF anode prepared by the above method allows for the controlled and sufficient construction of a continuous porous WO3 catalytic film on the PDA / CF surface, improving loading efficiency and electrode cycling stability. Simultaneously, it avoids the shedding of m-WO3 particles during the directional, large-scale deposition of m-WO3. Furthermore, pre-deposition reduces WO3 nanoparticle aggregation and reverse dissolution losses.

[0041] Furthermore, in step S1, magnetic stirring is used for stirring for 10 ± 1 min.

[0042] Furthermore, in step S2, the nitrogen flow rate is 40±2 mL / min, and the introduction time is 10±1 min.

[0043] Furthermore, in step S3, the pre-deposition time is 10±1 min, the scan rate is 0.1 V / s, the working conditions are 0.9 V to -0.9 V, and 100 scan cycles are performed.

[0044] Furthermore, in step S4, the voltage is maintained at -1.4 V, and electrodeposition is performed for 10 ± 1 min.

[0045] Furthermore, in step S1, m-WO3 needs to be ground before use.

[0046] Furthermore, m-WO3 is obtained through the following methods:

[0047] Mix phosphotungstic acid and ethanol in the appropriate proportions and stir until homogeneous;

[0048] KIT-6 was added to the mixed solution of phosphotungstic acid and ethanol during the stirring process, and the mixture was stirred magnetically at 55°C until dry to obtain a white powder.

[0049] The obtained white powder was heated to 500℃ within 240 min and calcined for 3 hours to obtain a light green powder;

[0050] After removing the light green powder with HF acid, stir for 1 hour and centrifuge.

[0051] The centrifuged material was washed three times each with distilled water and ethanol, and then dried in an oven at 60°C to obtain the m-WO3 product.

[0052] Furthermore, the PDA / CF anode is obtained through the following methods:

[0053] Dissolve dopamine hydrochloride in H2SO4 solution and purge with nitrogen gas for 15 min;

[0054] The CF electrode was immersed in a mixed solution of dopamine hydrochloride and H2SO4. A saturated calomel electrode was used as the reference electrode and a platinum wire as the counter electrode. Ammonium persulfate initiator was added. The PDA / CF electrode was obtained by scanning 150 cycles at a rate of 100 mV / s and an operating condition of -0.1 v to 0.7 v using the CV method.

[0055] The present invention also provides a carbon-based anode material for microbial fuel cells, which is obtained by the preparation method of the carbon-based anode material for microbial fuel cells described above.

[0056] This invention also provides an application of carbon-based anode materials for microbial fuel cells in microbial fuel cells.

[0057] Example 1

[0058] Preparation of mesoporous tungsten trioxide (m-WO3):

[0059] Weigh 1.8g of phosphotungstic acid into a beaker, add 25mL of ethanol and stir well. Add the solution to a 100mL beaker containing 2g of KIT-6 while stirring. Stir magnetically at 400 r / min at 55℃ until dry to obtain a white powder. Place the white powder in a crucible and calcine at 500℃ for 3 hours over 240 minutes. Transfer the light green powder from the crucible to a plastic beaker using 20mL of HF acid, stir for 1 hour, and then centrifuge. Wash the centrifuged product three times each with distilled water and ethanol, and then dry in an oven at 60℃ to obtain mesoporous tungsten trioxide (m-WO3), as shown in (…). Figure 3 As shown in a).

[0060] Fabrication of PDA / CF electrode:

[0061] 0.05M dopamine hydrochloride was dissolved in 50 mL of 0.5M H₂SO₄ solution, and nitrogen gas was purged for 15 min. A CF electrode was immersed in the mixed solution of dopamine hydrochloride and H₂SO₄, using a saturated calomel electrode as the reference electrode and a platinum wire as the counter electrode. 0.414 g of ammonium persulfate initiator was added. The CV method was used at a rate of 100 mV / s, operating at -0.1 V to 0.7 V. -0.002 150 scan cycles were performed to form the PDA / CF electrode.

[0062] Preparation of WO3-PDA / CF composite anode electrode:

[0063] After grinding the m-WO3 product, 100 mg was weighed and placed in a 50 mL beaker. 50 mL of 50 mmol / L PBS solution was added, and the mixture was magnetically stirred for 10 min. Then, a PDA / CF anode (3 cm × 3 cm × 0.5 cm) threaded with titanium wire was placed in the beaker, and nitrogen gas was introduced at a flow rate of 40 mL / min for 10 min. Using the PDA / CF anode as the working electrode, a Pt electrode as the counter electrode, and a saturated calomel electrode as the reference electrode, the electrochemical workstation was connected. Pre-deposition was performed using CV method for 10 min at a scan rate of 0.1 V / s, with a working range of 0.9 V to -0.9 V, for 100 cycles. The voltage was maintained at -1.4 V, and electrodeposition was performed for 10 min to obtain the WO3-PDA / CF anode, as shown in the figure. Figure 3 As shown in b).

[0064] Example 2

[0065] In this embodiment, the preparation of mesoporous tungsten trioxide (m-WO3) and the preparation of the PDA / CF electrode are the same as in Example 1. The difference is that when preparing the WO3-PDA / CF composite anode electrode, the magnetic stirring time is 9 min, the nitrogen flow rate is 38 mL / min, the inlet time is 9 min, the pre-deposition time is 9 min, and the electrodeposition time is 9 min.

[0066] Example 3

[0067] In this embodiment, the preparation of mesoporous tungsten trioxide (m-WO3) and the preparation of the PDA / CF electrode are the same as in Example 1. The difference is that when preparing the WO3-PDA / CF composite anode electrode, the magnetic stirring time is 11 min, the nitrogen flow rate is 42 mL / min, the inlet time is 11 min, the pre-deposition time is 11 min, and the electrodeposition time is 11 min.

[0068] The power generation performance of WO3-PDA / CF anode and CF anode was analyzed: Table 2 shows that when the anolyte of MFC is indole wastewater, the maximum power density of CF anode is 1497±19 mW / m 2 The maximum power density of the WO3-PDA / CF anode reaches 2946±36 mW / m 2 This represents an increase of 96.8%.

[0069] Table 1. Power generation performance of CF anodes modified with different ratios of polyaniline / dopamine.

[0070]

[0071] Table 2. Electrogenic performance of WO3-PDA / CF anode MFC with 200 mg / L indole as anolyte.

[0072]

[0073] The degradation capabilities of WO3-PDA / CF anode and CF anode were analyzed: For example... Figure 1 As shown, the MFC using the WO3-PDA / CF composite anode can completely degrade 200 mg / L indole within 180 h, while the MFC using the CF anode only degrades 64.52%.

[0074] Analysis of the anodic cyclic degradation capacity of WO3-PDA / CF: such as Figure 2 As shown, the MFC with WO3-PDA / CF composite anode maintained stable power generation performance after three months of operation, which helps to improve the power generation efficiency and wastewater treatment capacity of MFC and promotes the application of MFC in practical applications.

[0075] Microbial analysis was performed on the WO3-PDA / CF anode and the CF anode: such as Figure 4 As shown, compared to CF anodes, WO3-PDA / CF composite anodes can accelerate the adsorption and growth rate of anode microorganisms, increase the anode microbial load, activity and electron transport rate, and ultimately improve the power density output of MFC and wastewater treatment efficiency.

[0076] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for preparing a carbon-based anode material for a microbial fuel cell, characterized in that: Includes the following steps, Step S1: Mix m-WO3 and PBS solution in the appropriate ratio and stir until homogeneous; Step S2: Place the PDA / CF anode threaded with titanium wire into a mixed solution of m-WO3 and PBS, and purge with nitrogen gas; Step S3: Connect the PDA / CF anode as the working electrode, the Pt electrode as the counter electrode, and the saturated calomel electrode as the reference electrode to the electrochemical workstation, and perform pre-deposition using the CV method; Step S4: After pre-deposition, WO3-PDA / CF anode is obtained by electrodeposition.

2. The method for preparing the carbon-based anode material for microbial fuel cells according to claim 1, characterized in that: In step S1, magnetic stirring is used for stirring for 10 ± 1 min.

3. The method for preparing the carbon-based anode material for microbial fuel cells according to claim 2, characterized in that: In step S2, the nitrogen flow rate is 40±2 mL / min and the introduction time is 10±1 min.

4. The method for preparing the carbon-based anode material for microbial fuel cells according to claim 3, characterized in that: In step S3, the pre-deposition time is 10±1 min, the scan rate is 0.1 V / s, the working conditions are 0.9 V to -0.9 V, and 100 scan cycles are performed.

5. The method for preparing the carbon-based anode material for microbial fuel cells according to claim 4, characterized in that: In step S4, the voltage is maintained at -1.4 V, and electrodeposition is performed for 10 ± 1 min.

6. The method for preparing the carbon-based anode material for microbial fuel cells according to claim 5, characterized in that: In step S1, m-WO3 needs to be ground before use.

7. The method for preparing the carbon-based anode material for microbial fuel cells according to claim 6, characterized in that: m-WO3 is obtained through the following methods. Mix phosphotungstic acid and ethanol in the appropriate proportions and stir until homogeneous; KIT-6 was added to the mixed solution of phosphotungstic acid and ethanol during the stirring process, and the mixture was stirred magnetically at 55°C until dry to obtain a white powder. The obtained white powder was heated to 500℃ within 240 min and calcined for 3 hours to obtain a light green powder; After removing the light green powder with HF acid, stir for 1 hour and centrifuge. The centrifuged material was washed three times each with distilled water and ethanol, and then dried in an oven at 60°C to obtain the m-WO3 product.

8. The method for preparing the carbon-based anode material for microbial fuel cells according to claim 7, characterized in that: The PDA / CF anode is obtained through the following methods. Dissolve dopamine hydrochloride in H2SO4 solution and purge with nitrogen gas for 15 min; The CF electrode was immersed in a mixed solution of dopamine hydrochloride and H2SO4. A saturated calomel electrode was used as the reference electrode and a platinum wire as the counter electrode. Ammonium persulfate initiator was added. The PDA / CF electrode was obtained by scanning for 150 cycles at a rate of 100 mV / s and an operating condition of -0.1 V to 0.7 V using the CV method.

9. A carbon-based anode material for a microbial fuel cell, obtained by the preparation method of the carbon-based anode material for a microbial fuel cell according to any one of claims 1-8.

10. Application of a carbon-based anode material for microbial fuel cells in microbial fuel cells.

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