A bio-photovoltaic device based on a three-dimensional biofilm anode and a preparation method thereof

Abstract

The present invention discloses a bio-photovoltaic device based on a three-dimensional biofilm anode and a preparation method thereof, comprising the following steps: mixing a three-dimensional porous channel material with microalgae liquid for co-culture, so that the microalgae adsorb on the surface of the three-dimensional porous channel material and attach and grow on the three-dimensional porous channel material through the secreted EPS to obtain a three-dimensional biofilm anode; electrically connecting the cathode and the three-dimensional biofilm anode to a collector respectively, and sequentially stacking and assembling a cathode support frame, a cathode, a proton exchange membrane and an anode chamber; fixing the three-dimensional biofilm anode in the anode chamber and filling it with a culture solution, and fixing an antibacterial, waterproof and breathable membrane at the breathable port of the anode chamber to obtain the bio-photovoltaic device. The present invention improves the microalgae attachment amount through the three-dimensional biofilm anode and reduces the device resistance; the transmembrane transfer of photoelectrons is carried out through the outer electroactivity of the biofilm community to replace the indirect electron transfer mode of exogenous toxic electrolytes, which is beneficial to the long-term self-sustaining operation of the device and reduces the operation cost.

Description

Technical Field

[0001] The present invention relates to the technical field of biological photovoltaics, and particularly relates to a biological photovoltaic device based on a three-dimensional biofilm anode and a preparation method thereof. Background Art

[0002] Traditional photovoltaic power generation technology is mainly based on the photovoltaic effect of semiconductor materials, with high initial investment costs, high energy consumption and large pollution in the manufacturing process of photovoltaic panels. The biological photovoltaic system is mainly based on the photosynthesis of microalgae. Light energy is absorbed through the photosystem, water is split to generate electrons, and the electrons are transferred outside the microalgae cells and received by the anode. The electrons are then transferred to the cathode through an external circuit, and a reduction reaction occurs at the cathode, thus forming an electric current. Photosynthetic microorganisms have the characteristics of being renewable, with low production costs, no environmental pollution, and the ability to fix carbon dioxide. It is a new type of solar power generation technology that is environmentally friendly and meets the low-carbon development goal. In recent years, researchers have significantly improved the energy conversion efficiency of biological photovoltaic systems by optimizing algae culture conditions, improving electrode materials, designing efficient device configurations, reconstructing intracellular electron transfer pathways, etc. With the increasing maturity of technology, biological photovoltaic power generation is expected to become an important part of the green energy field.

[0003] Existing microalgae biological photovoltaic devices mainly adopt a two-chamber structure design, which is divided into an anode chamber and a cathode chamber, separated by a proton exchange membrane in the middle, and the electrodes are arranged face to face. Photosynthetic microorganisms carry out photosynthesis in the anode chamber. The electrons generated by the light reaction reach the cathode through the anode and a wire. The generated protons are transferred through the proton exchange membrane to the cathode chamber and then to the cathode, where they react with oxygen to generate water through a reduction reaction, thus generating an electric current.

[0004] Among them, the anode chamber is filled with algal liquid and exogenous electron carriers such as quinone compounds and potassium ferricyanide, relying on exogenous electron carriers to transfer electrons. Although exogenous electron carriers can promote indirect electron transfer, they generally have biological toxicity and will inhibit the metabolic activity of photosynthetic microorganisms; at the same time, the electrolyte needs to be replenished regularly, and the maintenance cost is high. In addition, the anode chamber with a sealed design to prevent contamination by miscellaneous bacteria makes the oxygen generated by microalgae photosynthesis unable to be discharged in time. The accumulated oxygen not only competes for the light reaction electrons through the "oxygen robbing electrons" phenomenon, reduces the electron transfer efficiency and causes the photocurrent to decay, but also inhibits the activity of the photosynthetic system and forms a feedback inhibition effect due to the too high dissolved oxygen concentration, significantly reducing the light energy conversion efficiency of microalgae. Moreover, two-dimensional anodes (such as stainless steel plates, copper plates, carbon papers, conductive glasses, etc.) are generally used, with insufficient specific surface area, relatively smooth surfaces, and it is not easy for microalgae to attach, and there are insufficient attachment points. Finally, affected by the two-chamber structure design and the characteristics of the electrolyte, the internal resistance of the device generally reaches the kΩ to MΩ level, resulting in significant energy loss, reduced energy conversion efficiency, and also affecting the stability of current output. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a bio-photovoltaic device based on a three-dimensional biofilm anode and a preparation method thereof. Microalgae are adsorbed on a carrier through electrostatic adsorption, and extracellular polymeric substances (EPS) secreted during the growth and metabolism process are used to attach and grow on the surface of the carrier to form a microalgae-based biofilm. The biofilm anode conducts transmembrane transfer of photoelectrons through the outer electroactivity of the biofilm community, thereby replacing the indirect electron transfer method that adds exogenous toxic electrolytes, which is beneficial to the long-term self-sustaining operation of the device; a three-dimensional porous material is used as the carrier to provide three-dimensional attachment points, and oxygen-containing functional groups are introduced through modification to improve the attachment efficiency of microorganisms.

[0006] To solve the above technical problems, the first aspect of the present invention provides a preparation method of a bio-photovoltaic device based on a three-dimensional biofilm anode, including the following steps:

[0007] S1. Immerse the three-dimensional porous material in strong acid for oxidation to introduce oxygen-containing functional groups. After sterilization, it is mixed and cultured with the microalgae solution. The microalgae are adsorbed on the surface of the three-dimensional porous material, and the EPS secreted by the microalgae is used to colonize it on the three-dimensional porous material through hydrogen bonds to form a microalgae biofilm, obtaining a three-dimensional biofilm anode;

[0008] S2. Electrically connect the cathode and the three-dimensional biofilm anode to the collector respectively, and stack and assemble the cathode support frame, the cathode, the proton exchange membrane, and the anode chamber in sequence;

[0009] S3. Fix the three-dimensional biofilm anode in the anode chamber, fill it with a culture solution, and then fix the antibacterial, waterproof, and breathable membrane at the breathable port of the anode chamber to obtain the bio-photovoltaic device based on the three-dimensional biofilm anode.

[0010] The present invention gets rid of the dependence on exogenous electron carriers. First, microalgae are adsorbed on the carrier through electrostatic adsorption, and extracellular polymeric substances (EPS) secreted during the growth and metabolism process of microalgae cells are used to attach and grow on the surface of the carrier to form a microalgae-based biofilm community; the photoelectrons generated by microalgae during photosynthesis are partially transferred to the extracellular environment under the light-dependent outer electroactivity characteristics, and the biofilm anode conducts transmembrane transfer of photoelectrons through the outer electroactivity of the biofilm community, thereby replacing the indirect electron transfer method that adds exogenous toxic electrolytes, which is beneficial to the long-term self-sustaining operation of the device; at the same time, there is no need to supplement the electrolyte, reducing the operating cost.

[0011] The present invention uses a three-dimensional porous material as the carrier, which has a large specific surface area, provides three-dimensional attachment points, and through surface modification by strong acid oxidation, oxygen-containing functional groups such as hydroxyl (-OH) and carboxyl (-COOH) are introduced, facilitating the attachment of EPS through hydrogen bonds, significantly improving the attachment efficiency of microorganisms, and the attachment amount reaches that of a two-dimensional electrode (1-10mg / cm 25 - 10 times that of (), effectively solving the problem of insufficient attachment points of the planar two-dimensional electrode, and the resistance drops to 10 - 100 Ω.

[0012] In the present invention, an antibacterial and waterproof breathable membrane is covered at the breathable port end of the anode chamber to form a "semi-open" structure. The antibacterial and waterproof breathable membrane prevents contamination by miscellaneous bacteria and promotes the circulation of oxygen in the anode chamber, timely discharging the oxygen generated by microalgae photosynthesis and reducing the inhibitory effect of excessive oxygen on photosynthesis.

[0013] Further, in S1, the three-dimensional porous material is selected from an aluminum wire winding body, a copper wire winding body, or carbon fiber wound with titanium wire.

[0014] Further, in S1, the strong acid is hydrochloric acid or nitric acid.

[0015] Further, in S1, the cultivation is specifically: carried out at 20 - 25 °C for x h: x h light-dark cycle for 3 - 5 days, where the light intensity is 40 - 60 μmol photons m -2 s -2 , and x is 10 - 14. The light-dark cycle is more conducive to the growth of the microalgae biofilm. The whole process is non-toxic, and the stress resistance and self-supporting structure of the biofilm improve the operation cycle and stability of the device.

[0016] Further, in S1, the OD of the microalgae liquid 620nm is 0.3 - 1.0.

[0017] Further, in S2, before the laminated assembly, there is also a step of sterilization by ultraviolet light.

[0018] Further, in S3, the pore size of the antibacterial and waterproof breathable membrane is 0.2 - 0.5 μm, the oxygen permeability ≥ 8000 cm 3 / (m 2 ·24 h·bar), and the interception rate of microorganisms with a diameter ≥ 0.22 μm is ≥ 90%.

[0019] Further, between the anode chamber and the proton exchange membrane, and between the cathode support frame and the cathode, edge sealing is achieved through gaskets with hollowed-out middles. Preferably, the material of the gasket is PDMS (polydimethylsiloxane).

[0020] The second aspect of the present invention provides a three-dimensional biofilm anode biophotovoltaic device obtained by the preparation method described in the first aspect, including an anode chamber. Anti-bacterial, waterproof and breathable membranes and proton exchange membranes are respectively arranged at the two open ends of the anode chamber. The proton exchange membrane is stacked with the cathode and fixed by a cathode support frame. The cathode support frame is connected to the anode chamber through a connecting piece. A three-dimensional biofilm anode is fixed in the anode chamber and filled with a culture solution. The three-dimensional biofilm anode and the cathode are respectively connected to a collector.

[0021] Further, the three-dimensional biofilm anode includes a three-dimensional porous channel material carrier and a microalgae biofilm colonized on the carrier.

[0022] Further, one side of the cathode away from the proton exchange membrane is in contact with air through a through hole located in the cathode support frame.

[0023] Further, it also includes two gaskets with hollowed-out middles, and the two gaskets are assembled between the anode chamber and the proton exchange membrane and between the cathode support frame and the cathode.

[0024] In the biophotovoltaic device based on the three-dimensional biofilm anode of the present invention, electrons and protons are generated through the photosynthesis of microalgae. Photoelectrons are transferred from inside the microalgae cells to the outside of the cells, reach the cathode through the anode and the collector, and protons are transferred to the cathode through the proton exchange membrane and react with oxygen in the air: O2 + 4H + + 4e - → 2H2O, thereby forming an electric current. This device can convert solar energy into electrical energy, realizing the utilization of solar energy and the fixation of carbon.

[0025] The beneficial effects of the present invention:

[0026] In the present invention, microalgae are adsorbed on the carrier through electrostatic adsorption and grow and attach to the surface of the carrier through the EPS secreted by them to form a biofilm community. The transmembrane transfer of photoelectrons is carried out through the outer electroactivity of the biofilm community, replacing the indirect electron transfer method of adding exogenous toxic electrolytes, which is beneficial to the long-term self-sustaining operation of the device. At the same time, there is no need to supplement the electrolyte, reducing the operating cost.

[0027] The present invention uses a three-dimensional porous channel material as the carrier, which has a large specific surface area, provides three-dimensional attachment points, and introduces oxygen-containing functional groups through surface modification, significantly improving the attachment efficiency of microorganisms. The attachment amount reaches 5-10 times that of the two-dimensional electrode, effectively solving the problem of insufficient attachment points of the planar two-dimensional electrode, and the resistance drops to 10-100Ω.

[0028] The present invention covers the breathable port end of the anode chamber with an antibacterial and waterproof breathable membrane to form a "semi-open" structure, preventing contamination by miscellaneous bacteria through the antibacterial and waterproof breathable membrane, promoting the circulation of oxygen in the anode chamber, discharging the oxygen generated by microalgae photosynthesis in a timely manner, and reducing the inhibitory effect of excessive oxygen on photosynthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 It is a schematic structural diagram of a three-dimensional biofilm anode biophotovoltaic device of the present invention;

[0031] Explanation of the reference numerals in the figure: 1. Anode chamber, 2. Antibacterial and waterproof breathable membrane, 3. Proton exchange membrane, 4. Cathode, 5. Cathode support frame, 6. Connector, 7. Three-dimensional biofilm anode, 8. Collector, 9. Gasket. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0033] This embodiment relates to a preparation method of a three-dimensional biofilm anode biophotovoltaic device, including the following steps:

[0034] S1. Immerse the three-dimensional porous material in strong acid for oxidation to introduce oxygen-containing functional groups, and after sterilization, mix it with the microalgae solution for culture. The microalgae adsorb on the surface of the three-dimensional porous material, and the EPS secreted by the microalgae colonizes it on the three-dimensional porous material through hydrogen bonds to form a microalgae biofilm, obtaining a three-dimensional biofilm anode;

[0035] S2. Electrically connect the cathode and the three-dimensional biofilm anode to the collector respectively, and stack and assemble the cathode support frame, cathode, proton exchange membrane, and anode chamber in sequence;

[0036] S3. Fix the three-dimensional biofilm anode in the anode chamber, fill it with a culture solution, and then fix the antibacterial and waterproof breathable membrane at the breathable port of the anode chamber to obtain the three-dimensional biofilm anode biophotovoltaic device.

[0037] In this embodiment, microalgae are attached to a carrier through electrostatic adsorption. The microalgae, secreted during their metabolic growth, adhere to the carrier surface and form a biofilm community dominated by the microalgae. Photoelectrons generated by the microalgae during photosynthesis are partially transferred to the extracellular environment due to their light-dependent exoelectroactivity. The biofilm anode transfers these photoelectrons across the membrane through the exoelectroactivity of the biofilm community, thus replacing the indirect electron transfer method that requires the addition of exogenous toxic electrolytes. This facilitates the long-term self-sustaining operation of the device and eliminates the need for electrolyte replenishment, reducing operating costs. A three-dimensional multi-porous material is used as a carrier, providing a large specific surface area and providing three-dimensional attachment points. Surface modification through strong acid oxidation introduces oxygen-containing functional groups such as hydroxyl (-OH) and carboxyl (-COOH), facilitating the attachment of EPS via hydrogen bonding. This significantly improves microbial attachment efficiency, achieving attachment rates 5-10 times that of two-dimensional electrodes, effectively addressing the problem of insufficient attachment points on planar two-dimensional electrodes and reducing resistance to 10-100Ω. The air vent of the anode chamber is covered with an antibacterial and waterproof breathable membrane to form a "semi-open" structure. The antibacterial and waterproof breathable membrane prevents contamination by foreign bacteria, promotes the circulation of oxygen in the anode chamber, and discharges the oxygen produced by the photosynthesis of microalgae in time, reducing the inhibitory effect of excessive oxygen on photosynthesis.

[0038] As a preferred embodiment, in S1, the strong acid is hydrochloric acid or nitric acid; the OD of the microalgae solution is 620nm The three-dimensional multi-porous material is selected from aluminum wire winding, copper wire winding or titanium wire winding carbon fiber; the culture is specifically: xh: xh light-dark cycle for 3-5 days at 20-25 ° C, wherein the light intensity is 40-60 μmol photonsm -2 s -2 , x is 10-14. The light-dark cycle is more conducive to the growth of microalgae biofilms. The entire process is non-toxic, and the biofilm's stress resistance and self-supporting structure improve the operating cycle and stability of the device.

[0039] As a preferred embodiment, in S2, a step of ultraviolet sterilization is also included before stacking and assembling.

[0040] As a preferred embodiment, in S3, the pore size of the antibacterial, waterproof and breathable membrane is 0.2-0.5 μm, and the oxygen permeability is ≥8000 cm 3 / (m 2 ·24h·bar), the interception rate of microorganisms with a diameter of ≥ 0.22 μm is ≥ 90%.

[0041] As a preferred embodiment, edge sealing is achieved between the anode chamber and the proton exchange membrane, and between the cathode support frame and the cathode by assembling a PDMS gasket with a hollow center.

[0042] Another embodiment provides a three-dimensional biofilm anode-based bio-photovoltaic device, as Figure 1 shown, which includes an anode chamber 1. Anti-bacterial, waterproof and breathable membranes 2 and a proton exchange membrane 3 are respectively arranged at the two open ends of the anode chamber 1. The proton exchange membrane 3 is stacked with the cathode 4 and fixed by a cathode support frame 5. The cathode support frame 5 is connected to the anode chamber 1 through a connecting member 6. A three-dimensional biofilm anode 7 is fixed in the anode chamber 1 and a culture solution is filled. The three-dimensional biofilm anode 7 and the cathode 4 are respectively connected to a collector 8. In this embodiment, the three-dimensional biofilm anode 7-based bio-photovoltaic device generates electrons and protons through the photosynthesis of microalgae. Photoelectrons are transferred from inside the microalgae cells to outside the cells, reach the cathode 4 through the anode via the collector 8, and protons are transferred to the cathode 4 through the proton exchange membrane 3 and react with oxygen in the air: O2 + 4H + + 4e - → 2H2O, thus forming an electric current. This device can convert solar energy into electrical energy to realize the utilization of solar energy and the fixation of carbon.

[0043] Specifically, the three-dimensional biofilm anode 7 includes a three-dimensional porous channel material carrier and a microalgae biofilm colonized on the carrier; the side of the cathode 4 away from the proton exchange membrane 3 is in contact with air through a through hole located in the cathode support frame 5.

[0044] As a preferred embodiment, it further includes two gaskets 9 with hollowed-out middles. The two gaskets 9 are assembled between the anode chamber 1 and the proton exchange membrane 3 and between the cathode 4 support frame and the cathode 4.

[0045] Example 1

[0046] This embodiment provides a preparation method of a three-dimensional biofilm anode-based bio-photovoltaic device, which includes the following steps:

[0047] (1) Preparation of a carbon fiber brush three-dimensional biofilm anode

[0048] Select mesophase pitch-based carbon fibers, soak them in acetone for 48 hours, and then rinse with deionized water to remove chemical residual impurities on the carbon fiber surface. Use titanium wires with a diameter of 0.8 mm and a length of 5 cm to wind the treated carbon fibers to finally make a carbon fiber brush. Immerse the carbon fiber brush in a 1.0 mol / L HCl solution and soak for 2 h to introduce oxygen-containing functional groups such as hydroxyl (-OH) and carboxyl (-COOH) through strong acid oxidation;

[0049] Sterilize the carbon fiber brush under high pressure (121 °C, 15 psi, 15 min), and place it in a sterilized glass bottle. Take 100 mL of standardized OD 620nmChlorella exponential phase culture solution with a concentration of 1.0 was placed in a centrifuge and centrifuged at a low speed (500 r / min, 1 min) to obtain the supernatant and the concentrated microalgae solution below. The supernatant was removed using a pipette. After adding the sterilized medium, the centrifuge tube was gently shaken and the microalgae solution below was gently pipetted to mix it evenly. Then, the microalgae solution was poured into a glass bottle and allowed to settle, and irradiated with a cool white fluorescent lamp (40 μmol photons m -2 s -2 ) at 25 °C for 3 days with a 12:12 h light-dark cycle to form a biofilm, obtaining a three-dimensional biofilm anode of carbon fiber brush with a microalgae attachment amount of 60 mg / cm 2 .

[0050] (2)Cathode preparation

[0051] Cut a carbon paper of 45 * 45 mm with a thickness of 0.2 mm, and soak the electrode in 1.0 mol / L NaOH to remove impurities on the electrode surface. Take out the electrode, rinse it with a large amount of deionized water until the last rinse liquid is neutral to remove the residual NaOH, and then dry the electrode.

[0052] (3)Preparation of antibacterial, waterproof and breathable membrane

[0053] Cut an antibacterial, waterproof and breathable membrane with a diameter of 30 mm and a pore size of 0.45 μm, and ultrasonically clean it with absolute ethanol for 5 minutes to remove surface impurities, and dry it for standby.

[0054] (4)Electrically connect the three-dimensional biofilm anode and the cathode to the collector.

[0055] (5)Sterilize the anode chamber, gasket, and cathode support frame under a 100 W ultraviolet lamp for 60 min.

[0056] (6)Assembly

[0057] Stack them from bottom to top in the order of cathode support frame, PDMS gasket, cathode, proton exchange membrane, PDMS gasket, and anode chamber, and tighten them with screws and nuts from top to bottom. Seal them through the elasticity of PDMS in the middle to prevent internal liquid leakage, and at the same time assist in positioning each functional layer.

[0058] (7)Anode chamber filling

[0059] Fix the three-dimensional biofilm anode of carbon fiber brush in the anode chamber, fill it with the medium, and finally cover it with the antibacterial, waterproof and breathable membrane to obtain a bio-photovoltaic device based on the three-dimensional biofilm anode. Place it at 20 °C and 80 μmol photons m -2 s -2 The detected resistance under illumination is only about 45 Ω.

[0060] Example 2

[0061] This embodiment provides a preparation method for a three-dimensional biofilm anode biophotovoltaic device, which includes the following steps:

[0062] (1) Preparation of a carbon fiber brush three-dimensional biofilm anode

[0063] Use a fluffy mass intertwined with multiple slender aluminum wires as a three-dimensional porous channel material, immerse it in a 2 mol / L NaOH solution for etching to remove surface dirt, immerse it in a concentrated nitric acid solution for 1 h, and introduce oxygen-containing functional groups such as hydroxyl (-OH) and carboxyl (-COOH) through strong acid oxidation;

[0064] After autoclaving (121 °C, 15 psi, 15 min), place it in a sterilized glass bottle. Take 100 mL of standardized Chlorella exponential-phase culture solution with OD 620nm = 1.0, put it into a centrifuge and centrifuge at a low speed (500 r / min, 1 min) to obtain the supernatant and the concentrated microalgae solution below. Use a pipette to remove the supernatant, add sterilized medium, gently shake the centrifuge tube and gently pipette the algae solution below to mix it evenly, then pour the algae solution into the glass bottle to settle, and irradiate it with a cool white fluorescent lamp (60 μmol photons m -2 s -2 )for 12:12 h light-dark cycle for 3 days to form a biofilm, obtaining a carbon fiber brush three-dimensional biofilm anode with a microalgae attachment amount of 70 mg / cm 2 .

[0065] (2)Cathode preparation

[0066] Cut a 45*45 mm carbon paper with a thickness of 0.2 mm, soak the electrode in 1.0 mol / L NaOH to remove impurities on the electrode surface. Take out the electrode, rinse it with a large amount of deionized water until the last rinse liquid is neutral to remove the residual NaOH, and then dry the electrode.

[0067] (3)Preparation of an antibacterial, waterproof and breathable membrane

[0068] Cut an antibacterial, waterproof and breathable membrane with a diameter of 30 mm and a pore size of 0.2 μm, ultrasonically clean it with absolute ethanol for 5 minutes to remove surface impurities, and dry it for later use.

[0069] (4)Electrically connect the three-dimensional biofilm anode and the cathode to the collector.

[0070] (5)Sterilize the anode chamber, gasket, and cathode support frame under a 100 W ultraviolet lamp for 60 min.

[0071] (6)Assembly

[0072] Stack them from bottom to top in the order of the cathode support frame, PDMS gasket, cathode, proton exchange membrane, PDMS gasket, and anode chamber, and tighten them with screws and nuts up and down. The elasticity of PDMS is used to achieve sealing in the middle to prevent internal liquid leakage and assist in positioning each functional layer at the same time.

[0073] (7)Anode chamber filling

[0074] Fix the carbon fiber brush three-dimensional biofilm anode in the anode chamber, add culture medium to fill it, and finally cover it with an antibacterial, waterproof and breathable membrane to obtain a bio-photovoltaic device based on a three-dimensional biofilm anode, and place it at 20 °C, 80 μmol photons m -2 s -2 The resistance is only about 80 Ω under light illumination.

[0075] The present invention has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions of the present invention and their implementation manners, and all of these fall within the scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

Claims

1. A preparation method of a three-dimensional biofilm anode biophotovoltaic device, characterized in that, It includes the following steps: S1. Immerse the three-dimensional porous channel material in strong acid for oxidation to introduce oxygen-containing functional groups. After sterilization, mix it with the microalgae solution for cultivation. The microalgae adsorb on the surface of the three-dimensional porous channel material, and the EPS secreted by the microalgae colonizes it on the three-dimensional porous channel material through hydrogen bonds to form a microalgae biofilm, obtaining a three-dimensional biofilm anode; S2. Electrically connect the cathode and the three-dimensional biofilm anode to the collector respectively, and stack and assemble the cathode support frame, the cathode, the proton exchange membrane, and the anode chamber in sequence; S3. Fix the three-dimensional biofilm anode in the anode chamber and fill it with a culture solution. Then fix the antibacterial, waterproof and breathable membrane at the breathable port of the anode chamber to obtain the bio-photovoltaic device based on the three-dimensional biofilm anode; Among them, in S1, the three-dimensional porous channel material is selected from an aluminum wire winding body, a copper wire winding body, or a carbon fiber wound with a titanium wire; Between the anode chamber and the proton exchange membrane, and between the cathode support frame and the cathode, edge sealing is achieved through gaskets with hollowed-out middles during assembly.

2. The preparation method of the three-dimensional biofilm anode-based bio-photovoltaic device according to claim 1, characterized in that, In S1, the cultivation is specifically as follows: It is carried out under the condition of 20 - 25 °C for x h: x h light-dark cycle for 3 - 5 days, where x is 10 - 14, and the light intensity is 40 - 60 μmol photons m -2 s -2 .

3. The preparation method of the three-dimensional biofilm anode-based bio-photovoltaic device according to claim 1, characterized in that, In S1, the OD of the microalgae liquid 620nm is 0.3 - 1.

0.

4. The preparation method of the three-dimensional biofilm anode-based bio-photovoltaic device according to claim 1, wherein In S3, the pore size of the antibacterial, waterproof and breathable membrane is 0.2 - 0.5 μm, the oxygen permeability ≥ 8000 cm 3 / (m 2 ·24h·bar), and the interception rate of microorganisms with a diameter ≥ 0.22 μm is ≥ 90%.

5. A three-dimensional biofilm anode-based biological photovoltaic device obtained by the preparation method according to any one of claims 1-4, characterized in that, It includes an anode chamber. Antibacterial, waterproof and breathable membranes and proton exchange membranes are respectively arranged at the two open ends of the anode chamber. The proton exchange membrane is stacked with the cathode and fixed by a cathode support frame. The cathode support frame is connected to the anode chamber through a connecting piece. The three-dimensional biofilm anode is fixed in the anode chamber and filled with a culture solution. The three-dimensional biofilm anode and the cathode are respectively connected to the collector.

6. The three-dimensional biofilm anode-based bio-photovoltaic device according to claim 5, wherein, The three-dimensional biofilm anode includes a three-dimensional porous channel material carrier and a microalgae biofilm attached to the carrier.

7. The preparation method of the three-dimensional biofilm anode-based bio-photovoltaic device according to claim 5, characterized in that, One side of the cathode away from the proton exchange membrane is in contact with air through a through hole located in the cathode support frame.

8. The three-dimensional biofilm anode-based bio-photovoltaic device according to claim 5, wherein It also includes two gaskets with hollowed-out middles. The two gaskets are assembled between the anode chamber and the proton exchange membrane and between the cathode support frame and the cathode.

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