WO2022000364A1 - Biomembrane electrode material based on special-shaped carbon fiber, and preparation method therefor and use thereof - Google Patents

Abstract

Provided are a biomembrane electrode material based on special-shaped carbon fiber, and a preparation method therefor and the use thereof. The biomembrane electrode material comprises a special-shaped cross-section carbon fiber fabric electrode substrate and a biomembrane loaded on the electrode substrate. The special-shaped cross-section carbon fiber fabric electrode substrate comprises a special-shaped cross-section carbon fiber fabric, and graphene and polypyrrole loaded on the surface of the fabric and in voids of carbon fibers, wherein the polypyrrole is loaded on the surface of the graphene and forms polypyrrole nanowires, which form a three-dimensional nano-conductive network structure. The use of the special-shaped cross-section carbon fiber fabric as an electrode loading matrix can increase the specific surface area of the carbon fiber fabric. In addition, the voids of the special-shaped cross-section are in communication with each other, such that a void network structure is formed. When graphene and polypyrrole are loaded on the surface and in the voids of the fabric, a three-dimensional conductive network structure can be formed, and the problem of a reduced biomembrane performance caused by the antimicrobial effect of graphene can be overcome. The use thereof in organic wastewater treatment has the characteristics of a high current density and a high degradation rate.

Description

A special-shaped carbon fiber-based biofilm electrode material and its preparation method and application technical field

The present invention relates to the technical field of biological electrode material and wastewater treatment, and relates to a special-shaped carbon fiber-based biological membrane electrode material and a preparation method and application thereof.

Background technique

The traditional methods of water pollution control include physical method, chemical method and biological method, but each method has certain limitations. The physical method has complex equipment requirements, high cost, and it is difficult to meet the discharge standard after one treatment; the chemical method is sometimes incomplete in treatment of pollutants, and there is a danger of secondary pollution; the biological method is limited by the type of target pollutants when it acts The effect on refractory pollutants is not obvious. The biofilm electrode method combines chemical and biological methods, which can effectively deal with pollutants that are difficult to biodegrade or incompletely treated by electrolysis, and become the preferred method for the treatment of refractory organic polluted wastewater.

The advantage is that the close adsorption of microorganisms on the electrode surface weakens the direct toxic effect of harmful substances on microorganisms, and improves the safety of system operation. In addition, a good conductivity-mass transfer relationship is formed between the biofilm and the substrate electrode, and the additional electrode potential has a certain influence on the enzyme catalysis, which may promote the oxidation or reduction of the target, thereby improving the degradation ability of the system.

In general, the process of treating organic pollutants in water by the biofilm electrode method is very complicated, and the treatment effect is closely related to the biofilm electrode material and solution composition, and the direct electro-oxidation and indirect electro-oxidation reactions often occur at the same time. Among them, the biofilm electrode material uses immobilization technology to immobilize microorganisms on the surface of the electrode to form a layer of biofilm. The biofilm is an electricity-generating microbial film, which oxidizes organic matter under anaerobic conditions and generates electric current, and at the same time obtains energy for growth and reproduction in the process of electron transfer. The advantage is that the close adsorption of microorganisms on the electrode surface weakens the direct toxic effect of harmful substances on microorganisms, and improves the safety of system operation. In addition, a good conductivity-mass transfer relationship is formed between the biofilm and the substrate electrode, and the additional electrode potential has a certain influence on the enzyme catalysis, which may promote the oxidation or reduction of the target, thereby improving the degradation ability of the system. Therefore, the preparation of biofilm electrode materials with high specific surface area and high electronic conductivity is the key to improve the efficiency of microbial fuel cells (MFC) in the treatment of organic wastewater.

In recent years, graphene has been used to modify MFC electrodes due to its large specific surface area and excellent electrical conductivity. Studies have shown that graphene oxide can be reduced to graphene by microorganisms with extracellular electron transfer function under anaerobic conditions, and there is direct electron transfer on the surface of extracellular electron transfer bacteria (electrogenic bacteria) and graphene oxide. The cells of the electrogenic bacteria can be captured by the graphene oxide nanosheets. The graphene oxide nanosheets act as a net to capture the electrogenic bacteria. At the same time, the graphene oxide nanosheets are reduced to graphene and self-assemble with the electrogenic bacteria. into graphene/electricity-generating bacteria net. This structure enables a large number of electrogenic bacteria to enter the formed graphene/biofilm matrix and form multiple conductive pathways, thereby facilitating electron transfer between the electrogenic bacteria and the electrodes. However, in the research of graphene-modified bioelectrode MFC, an important aspect that cannot be ignored is the antibacterial properties of graphene. Graphene will affect the growth of anode biofilm in the early stage, and will reduce the electrochemical activity and metabolic activity of the surface biofilm. When the biofilm matures After that, the contact surface between graphene and bacteria decreased, the adhesion of electrogenic bacteria on the surface of graphene biocathode increased, the electron transfer rate increased, and the biofilm metabolism and electrochemical performance were improved.

In view of this, the present invention constructs a nano-conductive network by structurally designing the electrode substrate of the biofilm electrode material, and then sequentially modifying the surface of the electrode substrate with graphene and polypyrrole nanowires, which significantly improves the specific surface area and the specific surface area of the biofilm electrode material. current density.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a special-shaped carbon fiber-based biofilm electrode material and its preparation method and application, so as to obtain a biofilm electrode material with high circuit density and high organic wastewater degradation rate.

For achieving the above object, the technical scheme adopted in the present invention is as follows:

A special-shaped carbon fiber-based biofilm electrode material, comprising a special-shaped cross-section carbon fiber fabric electrode substrate and a biofilm supported on the electrode substrate, the special-shaped cross-section carbon fiber fabric electrode substrate comprises a special-shaped cross-section carbon fiber fabric and its surface and Graphene and polypyrrole are loaded between the carbon fiber voids, and the polypyrrole is loaded on the surface of the graphene to form polypyrrole nanowires, forming a three-dimensional nano-conductive network structure.

Further, the special-shaped cross-section is a Y-shaped cross-section or a star-shaped cross-section.

Further, the carbon fiber fabric is carbon cloth or carbon felt made of polyacrylonitrile carbon fiber.

Further, the thickness of the carbon fiber fabric is 0.05 mm to 1 mm, and the spacing of the polyacrylonitrile carbon fibers is less than 100 μm.

Further, the biofilm is an electroactive microbial film.

A preparation method of the above-mentioned special-shaped carbon fiber-based biofilm electrode material, comprising the following steps:

S1. The special-shaped cross-section carbon fiber is made into a carbon fiber fabric with a thickness of 0.05mm to 1mm;

S2. after the carbon fiber fabric described in step S1 is impregnated and adsorbed in the graphene oxide solution, suction filtration is performed, and then the carbon fiber fabric loaded with graphene is obtained by reduction;

S3. The graphene-loaded carbon fiber fabric obtained in step S2 is used as the working electrode, the platinum electrode is used as the counter electrode, and the Ag/AgCl is used as the reference electrode to construct a three-electrode system, which is soaked in an electrolyte _{containing pyrrole monomer and NaClO 4 .} In , polypyrrole nanowires are grown on the surface of graphene-loaded carbon fiber fabric by electrochemical deposition process to obtain a special-shaped cross-section carbon fiber electrode substrate;

S4. The special-shaped cross-section carbon fiber electrode substrate obtained in step S3 is used as the working electrode, the platinum electrode is used as the counter electrode, and the Ag/AgCl is used as the reference electrode to construct a three-electrode system, which is immersed in an electrolyte inoculated with electroactive microorganisms. , culturing with direct current to obtain the special-shaped carbon fiber-based biofilm electrode material;

The electrolyte contains carbon source, PBS buffer, vitamins and trace elements.

Further, in step S3, the concentration of the pyrrole monomer is 50-100 mg/L, and the _{concentration of the NaClO 4} is 20-40 g/L.

Further, in step S4, the carbon source is organic matter in the organic wastewater to be treated, and the concentration of the organic matter is 50-120 mg/L.

Further, in step S4, the current of the direct current is 3-8 mA.

Application of the above-mentioned special-shaped carbon fiber-based biofilm electrode material, or the application of the special-shaped carbon fiber-based biofilm electrode material prepared by the above-mentioned preparation method, the special-shaped carbon fiber-based biofilm electrode material is used for biofilm electrolysis of organic wastewater deal with.

beneficial effect

Compared with the prior art, the special-shaped carbon fiber-based biofilm electrode material and its preparation method and application provided by the present invention have the following beneficial effects:

(1) In the special-shaped carbon fiber-based biofilm electrode material provided by the present invention, a special-shaped cross-section carbon fiber fabric is selected as the electrode load matrix. , which can increase the specific surface area of the carbon fiber fabric. When the special-shaped carbon fiber is made into a carbon fiber fabric with a certain thickness, the special-shaped carbon fibers are arranged together, and the gaps of the special-shaped cross-section are connected with each other to form a gap network structure. Graphene is loaded on the surface and voids of the carbon fibers, and the load is significantly increased, and the graphene filled in the voids of the carbon fibers is distributed in a two-dimensional line along the length of the carbon fibers, and then connected by the graphene loaded on the surface of the carbon fibers to form a three-dimensional conductive network structure. Then, polypyrrole is grown in situ on the surface of graphene to form a three-dimensional nano-conductive network structure composed of polypyrrole nanowires, and finally a biofilm is loaded on its surface, which can prevent the graphene from directly contacting the biofilm and overcome the antibacterial effect of graphene. Problems leading to reduced biofilm performance.

(2) The preparation method of the special-shaped carbon fiber-based biofilm electrode material provided by the present invention can obtain the special-shaped cross-section carbon fiber fabric electrode substrate with different graphene and polypyrrole loadings by controlling the thickness of the carbon fiber and the spacing between the carbon fibers, thereby The electrical conductivity of the electrode substrate is regulated. When graphene is loaded, after impregnation and adsorption, suction filtration is performed to improve the loading capacity and loading fastness of graphene oxide, and reduce the vacancies formed by unloaded graphene and polypyrrole, thereby improving the electron transfer rate of the electrode material.

(3) The special-shaped carbon fiber-based biofilm electrode material provided by the present invention can be used for the treatment of organic wastewater, and has the advantages of high current density, high treatment efficiency and high electrical degradation rate.

Description of drawings

Fig. 1 is the cross-sectional schematic diagram of the special-shaped carbon fiber of the special-shaped carbon fiber-based biofilm electrode material provided by the present invention;

2 is a schematic cross-sectional view of a special-shaped cross-section carbon fiber fabric of a special-shaped carbon fiber-based biofilm electrode material provided by the present invention;

3 is a schematic cross-sectional view of a carbon fiber fabric electrode substrate with a special-shaped cross-section of the special-shaped carbon fiber-based biofilm electrode material provided by the present invention.

detailed description

The technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, common All other embodiments obtained by the skilled person without creative work fall within the protection scope of the present invention.

The special-shaped carbon fiber-based biofilm electrode material provided by the present invention includes a special-shaped cross-section carbon fiber fabric electrode substrate and a biofilm supported on the electrode substrate. The special-shaped cross-section carbon fiber fabric electrode substrate includes a special-shaped cross-section carbon fiber fabric and its Graphene and polypyrrole are loaded between the surface and the carbon fiber voids, and the polypyrrole is loaded on the graphene surface to form polypyrrole nanowires, forming a three-dimensional nano-conductive network structure. The special-shaped cross-section carbon fiber fabric is selected as the electrode load matrix. In the special-shaped cross-section carbon fiber fabric, the irregular cross-section carbon fibers are arranged irregularly, so that there are more gaps between the special-shaped cross-section carbon fibers, which can increase the specific surface area of the carbon fiber fabric. Graphene is loaded on the surface and voids of the carbon fibers, and the load is significantly increased, and the graphene filled in the voids of the carbon fibers is distributed in a two-dimensional line along the length of the carbon fibers, and then connected by the graphene loaded on the surface of the carbon fibers to form a three-dimensional conductive network structure. Then, polypyrrole is grown in situ on the surface of graphene to form a three-dimensional nano-conductive network structure composed of polypyrrole nanowires, and finally a biofilm is loaded on its surface, which can prevent the graphene from directly contacting the biofilm and overcome the antibacterial effect of graphene. Problems leading to reduced biofilm performance.

Please refer to FIG. 1 and FIG. 3 , as a further improvement of the present invention, the special-shaped cross-section is a Y-shaped cross-section or a star-shaped cross-section. As can be seen from Figure 1, each carbon fiber with a Y-shaped cross-section or a star-shaped cross-section has more voids due to the bifurcated structure. It can be seen from Figures 2 and 3 that when carbon fibers are made into carbon fiber fabrics with a certain thickness, the carbon fibers are arranged together, and the voids of the special-shaped cross-sections are connected to each other to form a void network structure. After the graphene and polypyrrole are loaded into the voids, a three-dimensional conductive network structure is formed.

As a further improvement of the present invention, the carbon fiber fabric is carbon cloth or carbon felt made of polyacrylonitrile carbon fiber.

As a further improvement of the present invention, the thickness of the carbon fiber fabric is 0.05 mm˜1 mm, and the spacing of the polyacrylonitrile carbon fibers is less than 100 μm. Among them, the spacing of carbon fibers refers to the distance between any two adjacent carbon fibers when carbon fibers are made into fabrics, and the spacing of carbon fibers is too large, which is not conducive to the formation of a connected conductive network. By controlling the thickness of carbon fibers and the spacing between carbon fibers, special-shaped cross-section carbon fiber fabric electrode substrates with different graphene and polypyrrole loadings can be obtained, so as to control the electrical conductivity of the electrode substrate.

As a further improvement of the present invention, the biofilm is an electroactive microbial film. Such as aerobic bacteria or anaerobic bacteria microbial membrane, according to the type of organic matter in the organic wastewater to be treated, different microbial colonies are inoculated to realize the microbial electrochemical degradation treatment of organic wastewater.

A preparation method of the above-mentioned special-shaped carbon fiber-based biofilm electrode material, comprising the following steps:

S1. The special-shaped cross-section carbon fiber is made into a carbon fiber fabric with a thickness of 0.05 mm to 1 mm.

S2. after soaking and adsorbing the carbon fiber fabric described in step S1 in the graphene oxide solution for 1～4h, carry out suction filtration, and then reduce to obtain the carbon fiber fabric loaded with graphene; Graphene oxide is reduced to graphene by ultraviolet irradiation reduction method, electrochemical reduction method, etc.; after impregnation and adsorption, graphene oxide is adsorbed on the surface of carbon fiber fabric and between carbon fiber gaps, and then through suction filtration, the loading capacity of graphene oxide is increased and load fastness, overcoming the problem of reduced electron transport rate of electrode materials due to vacancies formed by unloading.

S3. The graphene-loaded carbon fiber fabric obtained in step S2 is used as the working electrode, the platinum electrode is used as the counter electrode, and the Ag/AgCl is used as the reference electrode to construct a three-electrode system, which is soaked in an electrolyte _{containing pyrrole monomer and NaClO 4 .} In , under a constant voltage of 0.8V, polypyrrole nanowires were grown on the surface of graphene-loaded carbon fiber fabric by electrochemical deposition process to obtain a special-shaped cross-section carbon fiber electrode substrate;

The concentration of the pyrrole monomer is 50-100 mg/L, and the _{concentration of the NaClO 4} is 20-40 g/L. Through the electrochemical deposition process, it is helpful to form polypyrrole nanowires and a uniform conductive network structure on the surface of graphene, thereby improving the electron transport rate and current density of the electrode material.

S4. The special-shaped cross-section carbon fiber electrode substrate obtained in step S3 is used as the working electrode, the platinum electrode is used as the counter electrode, and the Ag/AgCl is used as the reference electrode to construct a three-electrode system, which is immersed in an electrolyte inoculated with electroactive microorganisms. , culturing with direct current to obtain the special-shaped carbon fiber-based biofilm electrode material.

The electrolyte contains carbon source, PBS buffer, vitamins and trace elements.

Further, in step S4, the carbon source is organic matter in the organic wastewater to be treated, such as phenol, fluorine-containing organic matter, nitrogen-containing organic matter, and phosphorus-containing organic matter. The concentration of the organic matter is 50-120 mg/L. The formation mechanism of the biofilm is as follows: the inoculated electroactive microorganisms first adhere to the surface of the carbon fiber electrode substrate with special-shaped cross-section to form microcolonies and fuse into the base layer of the biofilm; at the same time, extracellular polymers are produced and released, followed by the formation of microcolonies. With the extension of the culture time, the structure of the biofilm became more complicated and developed into a mature biofilm. The biofilm on the surface is mainly composed of microbial cells, extracellular polymers and inorganic ions in the water system, and the water content in the film is more than 95%, forming a porous structure state. The application principle of biofilm electrodes is to electrically stimulate microorganisms that already have the ability to remove certain pollutants, increase their metabolism or consume pollutants, and use the charge transfer between the electrode substrate and the pollutants. Double degradation.

Further, in step S4, the current of the direct current is 3-8 mA.

Application of the above-mentioned special-shaped carbon fiber-based biofilm electrode material, or the application of the special-shaped carbon fiber-based biofilm electrode material prepared by the above-mentioned preparation method, the special-shaped carbon fiber-based biofilm electrode material is used for biofilm electrolysis of organic wastewater deal with. The treatment method is as follows: using the special-shaped carbon fiber-based biofilm electrode material as the working electrode of the microbial fuel cell, preparing the organic wastewater to be treated into an electrolyte, and performing electrolytic treatment. The basic processes of biological metabolism of organic pollutants include access to substrates, adsorption of solid substrates, secretion of extracellular enzymes, absorption of permeable substances and intracellular metabolism. Microorganisms first grow close to a certain substrate, and then adsorb on the surface of the substrate. When faced with macromolecular multimeric compounds, microorganisms secrete extracellular enzymes to hydrolyze part of macromolecules into soluble products of small molecules, which are easily degraded and mineralized by other microorganisms. Small molecule products enter cells through the cell membrane through four modes: simple diffusion, facilitated diffusion, active transport and group translocation, and are degraded through peripheral metabolic pathways.

Example 1

A special-shaped carbon fiber-based biofilm electrode material, comprising a Y-shaped cross-section PAN carbon fiber fabric electrode substrate and a biofilm supported on the electrode substrate, the Y-shaped cross-section PAN carbon fiber fabric electrode substrate includes a Y-shaped cross-section PAN Graphene and polypyrrole supported between the carbon fiber fabric and its surface and carbon fiber voids, the polypyrrole is supported on the graphene surface to form polypyrrole nanowires, and constitute a three-dimensional nano-conductive network structure. The preparation method is as follows:

S1. The Y-shaped cross-section PAN carbon fiber is made into a carbon fiber cloth with a thickness of 0.1 mm and a carbon fiber spacing of 80-100 μm;

S2. after the carbon fiber cloth described in step S1 is soaked and adsorbed in the graphene oxide solution for 2h, suction filtration is performed, after the soaking and adsorption, the graphene oxide is adsorbed on the surface of the carbon fiber cloth and between the carbon fiber gaps, and then by suction filtration, to improve oxidation The loading amount and loading fastness of graphene can overcome the problem that the electron transport rate of the electrode material is reduced due to the vacancies formed by unloading, and then the graphene-loaded carbon fiber cloth is obtained by electrochemical reduction method;

S3. The graphene-loaded carbon fiber cloth obtained in step S2 is used as the working electrode, the platinum electrode is used as the counter electrode, and the Ag/AgCl is used as the reference electrode to construct a three-electrode system, and the concentration of immersed in the pyrrole monomer is 65mg/L, In _{an electrolyte with a concentration of NaClO 4} of 30 g/L, under a constant voltage of 0.8 V, polypyrrole nanowires were grown on the surface of the graphene-loaded carbon fiber fabric by an electrochemical deposition process to obtain a special-shaped cross-section carbon fiber electrode substrate; The electrochemical deposition process helps to form polypyrrole nanowires and a uniform conductive network structure on the surface of graphene, thereby improving the electron transfer rate and current density of the electrode material;

S4. The Y-shaped cross-section PAN electrode substrate obtained in step S3 is used as the working electrode, the platinum electrode is used as the counter electrode, and the Ag/AgCl is used as the reference electrode to construct a three-electrode system. In the electrolyte, the direct current of 5mA is used for cultivation to obtain a Y-shaped cross-section PAN-based biofilm electrode material; the electrolyte contains 100mg/L carbon source, 50mmol/L PBS buffer, 10ml/L vitamins and trace amounts. element.

Comparative Example 1

A special-shaped carbon fiber-based biofilm electrode material, compared with Example 1, the difference is that the PAN carbon fiber fabric is a circular cross-section PAN carbon fiber, the other is roughly the same as Example 1, and will not be repeated here.

Comparative Example 2

A special-shaped carbon fiber-based biofilm electrode material, compared with Example 1, is different in that it includes a Y-shaped cross-section PAN carbon fiber fabric and a biofilm loaded on the carbon fiber fabric, that is, unloaded graphene and polypyrrole, prepared The method does not include steps S2 and S3, and the others are substantially the same as those in Embodiment 1, which will not be repeated here.

Comparative Example 3

A special-shaped carbon fiber-based biofilm electrode material, compared with Example 1, the difference is that the Y-shaped cross-section PAN carbon fiber fabric electrode substrate comprises a Y-shaped cross-section PAN carbon fiber fabric and its surface and the carbon fiber voids between Supported graphene, i.e. unsupported polypyrrole. Others are substantially the same as those in Embodiment 1, and are not repeated here.

Comparative Example 4

A special-shaped carbon fiber-based biofilm electrode material, compared with Example 1, the difference is that the Y-shaped cross-section PAN carbon fiber fabric electrode substrate comprises a Y-shaped cross-section PAN carbon fiber fabric and the surface between the surface and the carbon fiber voids Supported polypyrrole, i.e. unsupported graphene. Others are substantially the same as those in Embodiment 1, and are not repeated here.

Examples 2 to 4 and Comparative Example 5

Compared with Example 1, the special-shaped carbon fiber-based biofilm electrode materials provided in Examples 2 to 4 and Comparative Example 5 are different in that the thickness of the Y-shaped cross-section PAN carbon fiber and the carbon fiber gap are shown in Table 1. Others are substantially the same as those in Embodiment 1, and are not repeated here.

Table 1 Preparation conditions of Examples 2-4 and Comparative Example 5

sample	Thickness of Y-shaped cross-section PAN carbon fiber (mm)	Pitch of carbon fibers (μm)
Example 2	0.05	80～100
Example 3	1	80～100
Example 4	0.1	60～80
Comparative Example 5	0.1	120

Application examples 1 to 4 and application comparison examples 1 to 5

Application Examples 1 to 4 and Application Comparative Examples 1 to 5 are respectively using the Y-shaped carbon fiber-based biofilm electrode materials prepared in Examples 1 to 4 and Comparative Examples 1 to 5 for the treatment of organic wastewater containing phenol. The treatment methods are as follows: The Y-shaped carbon fiber-based biofilm electrode material is used as the working electrode of the microbial fuel cell, and the organic wastewater containing phenol is prepared into an electrolyte, and electrolytic treatment is performed. The phenol concentration in the organic wastewater is 1500mg/L, and the COD content is 2500mg /L.

Table 2 Electrical performance of application examples 1 to 4 and application comparison examples 1 to 5

sample	Current density (mA/cm 2 )	Phenol removal rate (%)	COD conversion rate (%)
Application example 1	278	99.9	95.8
Application example 2	269	99.8	95.6
Application example 3	280	99.9	95.6
Application example 4	271	99.9	95.7
Application Example 1	228	96.3	90.2

Application Comparative Example 2	109	89.8	81.2
Application Comparative Example 3	128	91.9	83.1
Application Comparative Example 4	137	92.8	85.0
Application Comparative Example 5	232	97.6	90.7

As can be seen from Table 2, the Y-shaped carbon fiber-based biofilm electrode material prepared by the preparation method provided by the present invention is used for bioelectric degradation treatment of phenolic organic wastewater, the removal rate of phenol is as high as 99%, and the conversion rate of COD is as high as 95% above. When the carbon fiber has a circular cross-section, the current density, phenol removal rate and COD conversion rate are significantly reduced, just because the carbon fiber with a circular cross-section is densely arranged, the carbon fiber has fewer voids, and the specific surface area is reduced, resulting in graphene and polymer The loading of pyrrole is reduced, and the three-dimensional conductive network structure cannot be formed through voids and surface loading. When the carbon fiber has a Y-shaped cross section, but no graphene and polypyrrole are supported, the current density, phenol removal rate and COD conversion rate decrease most obviously. When only graphene is supported, the current density, phenol removal rate and COD conversion rate are low. This is probably because when the graphene surface is not loaded with polypyrrole, the antibacterial effect of graphene will inhibit the growth of biofilms to a certain extent, thereby reducing its performance. When the spacing of carbon fibers is greater than 100 μm, the current density, phenol removal rate and COD conversion rate also decrease. This may be because the spacing of carbon fibers is too large, which is not conducive to the formation of a connected conductive network, and the vacancies formed by graphene and polypyrrole are not supported. increase, resulting in a decrease in the electron transport rate of the electrode material.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the inventive concept thereof shall be included within the protection scope of the present invention.

Claims (10)

1. A special-shaped carbon fiber-based biofilm electrode material, characterized in that it includes a carbon fiber fabric electrode substrate with a special-shaped cross-section and a biofilm supported on the electrode substrate, and the carbon fiber fabric electrode substrate with a special-shaped cross-section comprises a carbon fiber fabric with a special-shaped cross-section Graphene and polypyrrole supported between its surface and carbon fiber voids, and the polypyrrole is supported on the graphene surface to form polypyrrole nanowires, forming a three-dimensional nano-conductive network structure.
2. The special-shaped carbon fiber-based biofilm electrode material according to claim 1, wherein the special-shaped cross-section is a Y-shaped cross-section or a star-shaped cross-section.
3. The special-shaped carbon fiber-based biofilm electrode material according to claim 2, wherein the carbon fiber fabric is carbon cloth or carbon felt made of polyacrylonitrile carbon fiber.
4. The special-shaped carbon fiber-based biofilm electrode material according to claim 3, wherein the thickness of the carbon fiber fabric is 0.05 mm to 1 mm, and the spacing between the polyacrylonitrile carbon fibers is less than 100 μm.
5. The special-shaped carbon fiber-based biofilm electrode material according to claim 1, wherein the biofilm is an electroactive microbial film.
6. A method for preparing a special-shaped carbon fiber-based biofilm electrode material according to any one of claims 1 to 5, characterized in that, comprising the following steps:

   S1. The special-shaped cross-section carbon fiber is made into a carbon fiber fabric with a thickness of 0.05mm to 1mm;

   S2. after the carbon fiber fabric described in step S1 is impregnated and adsorbed in the graphene oxide solution, suction filtration is performed, and then the carbon fiber fabric loaded with graphene is obtained by reduction;

   S3. The graphene-loaded carbon fiber fabric obtained in step S2 is used as the working electrode, the platinum electrode is used as the counter electrode, and the Ag/AgCl is used as the reference electrode to construct a three-electrode system, which is soaked in an electrolyte _{containing pyrrole monomer and NaClO 4 .} In , polypyrrole nanowires are grown on the surface of graphene-loaded carbon fiber fabric by electrochemical deposition process to obtain a special-shaped cross-section carbon fiber electrode substrate;

   S4. The special-shaped cross-section carbon fiber electrode substrate obtained in step S3 is used as the working electrode, the platinum electrode is used as the counter electrode, and the Ag/AgCl is used as the reference electrode to construct a three-electrode system, which is immersed in an electrolyte inoculated with electroactive microorganisms. , culturing with direct current to obtain the special-shaped carbon fiber-based biofilm electrode material;

   The electrolyte contains carbon source, PBS buffer, vitamins and trace elements.
7. The method for preparing a special-shaped carbon fiber-based biofilm electrode material according to claim 6, wherein in step S3, the concentration of the pyrrole monomer is 50-100 mg/L, and the concentration of _{the NaClO 4 is 20-100 mg/L.} 40g/L.
8. The method for preparing a special-shaped carbon fiber-based biofilm electrode material according to claim 6, wherein in step S4, the carbon source is organic matter in the organic wastewater to be treated, and the concentration of the organic matter is 50-120 mg /L.
9. The method for preparing a special-shaped carbon fiber-based biofilm electrode material according to claim 6, wherein in step S4, the current of the direct current is 3-8 mA.
10. A special-shaped carbon fiber-based biofilm electrode material according to any one of claims 1 to 5, or the application of the special-shaped carbon fiber-based biofilm electrode material prepared by the preparation method according to any one of claims 6 to 9, which It is characterized in that the special-shaped carbon fiber-based biofilm electrode material is used for biofilm electrolysis treatment of organic wastewater.

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