A photo-electric-microbial composite system for simultaneous remediation of micropollutants in high-transparency water and sediment phases and its application

Abstract

This invention discloses a photoelectric-microbial composite system for the simultaneous remediation of micropollutants in a high-transparency water-sediment dual phase, and its application, relating to water treatment and ecological restoration technologies. The invention designs a photoelectric-microbial composite system that integrates the unique solid-liquid interface of a high-transparency water-sediment composite system with a microbial fuel cell. Furthermore, for the first time, a piezoelectric polymer and perovskite are combined as the cathode, and piezoelectric photocatalytic materials and semi-artificial photosynthesis are introduced at the anode to enhance the system's redox process. This creates a novel photoelectric-microbial fuel cell model, enhancing the pollutant reduction efficiency of the sediment-overlying water composite system, while also achieving energy conservation and recycling.

Description

Technical Field

[0001] The present invention relates to the fields of water treatment technology and ecological restoration technology, and in particular to a light-electricity-microorganism composite system for synchronously repairing micropollutants in high-transparency water and sediment phases and its application. Background Art

[0002] A solid-liquid system refers to a complex ecosystem composed of a layer of sediment at the bottom of a sea or river and a layer of water covering it (the overlying aquifer). Sediments are primarily composed of solid particles that have settled to the bottom of a body of water. These particles are generally insoluble in water and may contain various minerals, organic matter, and microorganisms. The overlying aquifer is the layer of water that covers the sediments, and its thickness can vary depending on factors such as geographic location, water depth, and current velocity.

[0003] The overlying water layer and sediment layer maintain a close connection through the exchange of substances and energy flow. A deeper understanding of the structure and function of this system can help us better understand the evolution of the aquatic environment, predict and assess the impact of human activities on the aquatic environment, and develop effective environmental protection and governance strategies. Furthermore, this system has broad application prospects in wastewater treatment, ecological restoration, and other fields.

[0004] Piezoelectric photocatalysis is a novel energy conversion technology that combines the piezoelectric effect with photocatalytic reactions, converting mechanical and light energy into electrical energy to drive chemical reactions. In piezoelectric photocatalysis, a photocatalyst is combined with a piezoelectric material to form a piezoelectric photocatalytic composite. When this composite is exposed to both light and mechanical stress, the electric field generated by the piezoelectric effect enhances the photocatalyst's light absorption and charge separation efficiency, thereby accelerating the chemical reaction.

[0005] Semi-artificial photosynthesis, a biocatalytic process driven by a hybrid material-organism system, cleverly combines efficient light-harvesting materials with highly selective biocatalytic mechanisms, aiming to achieve highly efficient and specific conversion of light energy into chemical energy. Key approaches include combining natural light as a light absorber with nanomaterials, and combining materials as light absorbers with enzymes or whole-cell microbial catalysts.

[0006] Microbial fuel cells are an innovative technology that integrates energy production and wastewater purification. They cleverly utilize microorganisms as biocatalysts to oxidize organic and inorganic substances while generating electricity. Compared to traditional wastewater treatment processes, microbial fuel cells offer advantages such as no secondary pollution and no need for aeration facilities. In a microbial fuel cell system, microorganisms catalyze the decomposition of organic matter in wastewater in the anaerobic anode region, producing protons and electrons. Protons reach the cathode through a specific transport mechanism, while electrons are transferred to the cathode through an external circuit. At the cathode, the protons and electrons combine with external electron acceptors, completing the electron transport chain, achieving efficient wastewater purification and energy recovery.

[0007] Currently, the combined pollution of water and sediments in solid-liquid systems, particularly micropollutants in highly transparent water, has become a significant challenge in environmental remediation. The inventors believe that there is currently no research on coupling photovoltaics with microbial fuel cells to enhance the treatment of both the solid and liquid phases of highly transparent water-sediment systems. Therefore, addressing these technical issues remains a challenge currently faced by those skilled in the art.

[0008] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0009] In response to the above technical problems, the embodiments of the present invention provide a photo-electric-microbial composite system for synchronously repairing micropollutants in high-transparency water and sediment phases and its application to solve the problems raised in the above background technology.

[0010] A photo-electric-microorganism composite system comprising: an anode, a cathode, an external resistor, an underwater light source, and an electroactive bacteria / FeS hybrid material;

[0011] The lower end of the anode is inserted into the sediment layer and the upper end extends to the overlying water layer; C-BiOBr / MXene material is in situ grown at the position where the anode is exposed in the overlying water layer;

[0012] The cathode floats on the overlying water layer; the cathode is a piezoelectric photocatalytic film PVDF-HFP, which is loaded with La 1-x Ca x NiO3;

[0013] The external resistor is connected to the anode and the cathode via a first wire;

[0014] The underwater light source is set in the overlying water layer;

[0015] The electroactive bacteria / FeS hybrid material is added into the sediment layer; the electroactive bacteria / FeS hybrid material includes electroactive bacteria and FeS.

[0016] Preferably, it also includes a solar panel; the solar panel is externally placed above the overlying water layer, and is used to provide electrical energy for the underwater light source.

[0017] Preferably, the wavelength of the underwater light source is greater than 300 nm, and the power of the underwater light source is less than 60 W.

[0018] Preferably, the main body material of the anode is iron wire.

[0019] Preferably, the C-BiOBr / MXene material includes a highly conductive two-dimensional material MXene and BiOBr; the highly conductive two-dimensional material MXene and BiOB are compounded together by electrostatic adsorption; and the surface of BiOBr is modified by CND.

[0020] Preferably, the anode comprises a plurality of anodes, which are connected in series; and stones are wound between adjacent anodes.

[0021] Preferably, the piezoelectric photocatalytic film PVDF-HFP is a porous electrode film made of a flexible polymer material polyvinylidene fluoride-hexafluoropropylene copolymer.

[0022] Preferably, the piezoelectric photocatalytic film PVDF-HFP is composed of a crystalline portion of polyvinylidene fluoride and an amorphous portion of hexafluoropropylene.

[0023] Preferably, the electroactive bacterium is Shewanella.

[0024] An application of the above-mentioned photo-electric-microorganism composite system in water ecological restoration projects.

[0025] The embodiments of the present invention provide a light-electricity-microorganism composite system for synchronously repairing micropollutants in high-transparency water and sediment phases and its application, which has the following beneficial effects:

[0026] 1. This invention constructs a photo-electric-microbial composite system. The composite system combines the mechanical energy generated by sewage flow and the light energy supplied under natural light conditions, and uses electroactive microorganisms, mainly Shewanella, to synergistically enhance the efficiency of pollution treatment in both solid and liquid phases.

[0027] 2. Compared with other processes, this invention introduces a microbial fuel cell system and a nanomaterial photo-electrocatalytic enhanced redox process, reducing the problems of excessively thick anode biofilms in fuel cells and high resistance during transmission that affect electron mass transfer, thereby accelerating the removal efficiency of solid-liquid two-phase composite pollution.

[0028] 3. The present invention designs multiple anode electrodes in series, which can adjust the number of anodes according to the region and the size of the pollution range, or flexibly adjust the thickness and size of the cathode electrode, thereby reducing equipment costs and ensuring the recycling of resources;

[0029] 4. The light-electricity-microorganism composite system designed by the present invention is easy to build, easy to recycle, easy to handle, and has high applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the structure of the light-electricity-microorganism composite system of the present invention;

[0031] Figure 2 A top view of the light-electricity-microorganism composite system of the present invention;

[0032] Figure 3 This is a left side view of the light-electricity-microorganism composite system of the present invention;

[0033] In the figure, 1-solar panel; 2-cathode; 3-first wire; 4-second wire; 5-resistor; 6-C-BiOBr / MXene material; 7-main material; 8-sediment layer; 9-electroactive bacteria / FeS hybrid material; 10-underwater light source; 11-stone. DETAILED DESCRIPTION

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0035] In response to the above technical problems, an embodiment of the present invention provides a photo-electric-microbial composite system for synchronously repairing micropollutants in high-transparency water and sediment phases and its application to solve the problems raised in the above background technology.

[0036] A photo-electric-microorganism composite system, comprising: an anode 6, a cathode 2, an external resistor 5, an underwater light source 10, and an electroactive bacteria / FeS hybrid material 9;

[0037] The lower end of the anode 6 is inserted into the sediment layer 8 and the upper end thereof extends to the overlying water layer; the lower end of the anode 6 is inserted into the sediment layer 8, which not only serves to fix the anode 6, but also the lower end of the anode 6 is deeply buried in the sediment layer 8, which can provide a growth and breeding attachment point for microorganisms;

[0038] The anode 6 is exposed to the overlying water layer where C-BiOBr / MXene material is grown in situ;

[0039] Cathode 2 floats on the overlying water layer; cathode 2 is a piezoelectric photocatalytic film PVDF-HFP, on which perovskite metal oxide (La 1-x Ca x NiO3);

[0040] The external resistor 5 is connected to the anode 6 and the cathode 2 via the first wire 3;

[0041] The underwater light source 10 is disposed in the overlying water layer;

[0042] The electroactive bacteria / FeS hybrid material 9 is added to the sediment layer 8; the electroactive bacteria / FeS hybrid material 9 includes electroactive bacteria and FeS; the electroactive bacteria are preferably Shewanella.

[0043] Among them, electroactive bacteria metabolize carbon sources under anaerobic conditions to produce hydrogen sulfide gas, which reacts with pyrite and self-assembles into a semi-artificial photosynthesis system.

[0044] The C-BiOBr / MXene material on the anode 6 is subjected to the pressure of the mechanical energy generated by the water flow, which causes lattice deformation of the C-BiOBr, which can accelerate the photocatalytic removal of pollutants and synergistically reduce heavy metal (Zn, Cu) ions, thereby reducing the toxicity of heavy metals.

[0045] La is loaded on the piezoelectric photocatalytic film PVDF-HFP of cathode 2 1-x Ca x NiO3, the doped cathode exhibits metallic conductivity and is placed at the cathode as the main catalyst for the reduction reaction.

[0046] After receiving the underwater light source on the surface of the sediment layer 8, some electroactive bacteria / FeS hybrid materials stimulate the separation of electron-hole pairs, generating active groups to participate in the degradation of pollutants at the solid-liquid interface; the electroactive bacteria quickly transfer electrons in FeS to the surface of the anode 6 through a special extracellular electron transfer mechanism.

[0047] This embodiment also includes a solar panel 1, which is externally positioned above the overlying water layer and is used to provide electrical energy for an underwater light source 10. The solar panel 1 is electrically connected to the underwater light source 10 via a second conductor 4. The solar panel 1 is configured to collect natural light to provide electrical energy for the underwater light source 10. The solar panel 1 is preferably 50 cm x 50 cm in size.

[0048] In this embodiment, the wavelength of the underwater light source 10 is greater than 300 nm, and the power of the underwater light source 10 is less than 60 W. The wavelength of the light source greater than 300 nm is within the visible light range, and the power less than 60 W is equivalent to the size of a halogen bulb.

[0049] In this embodiment, the main body material 7 of the anode 6 is iron wire; the iron wire can be made into a rice ear shape.

[0050] In this example, the C-BiOBr / MXene material comprises the highly conductive two-dimensional material MXene and bismuth oxybromide (BiOBr). The highly conductive two-dimensional MXene and BiOB are bonded together through electrostatic adsorption. The BiOBr surface is modified with carbon nanodots (CNDs). The C-BiOBr / MXene material exhibits piezoelectric photocatalytic properties.

[0051] In this embodiment, the anode 6 includes multiple anodes 6, and the multiple anodes 6 are connected in series; specifically, the number of anodes 6 can be set according to the difference in regional area. The anode 6 can be detachably fixed and inserted into the sediment layer 8. The detachable and fixed assembly and unassembly facilitates the replacement and recycling of the anode 6.

[0052] Stones 11 are wound between adjacent anodes 6 . The purpose of winding the stones 11 between adjacent anodes 6 is to stabilize the height of the anodes 6 in the transverse direction and to extend the depth of the sediment layer 8 in the longitudinal direction.

[0053] In this embodiment, the piezoelectric photocatalytic film PVDF-HFP is a porous electrode film made of a flexible polymer material polyvinylidene fluoride-hexafluoropropylene copolymer.

[0054] In this embodiment, the piezoelectric photocatalytic membrane, PVDF-HFP, is composed of a crystalline portion of polyvinylidene fluoride (PVDF) and an amorphous portion of hexafluoropropylene (HFP). PVDF-HFP combines the excellent chemical stability of HFP and vinylidene fluoride (VDF) with the flexibility and good processing properties of HFP, allowing it to gently sway with the flow of water.

[0055] It should be noted that the specific working principle of the light-electricity-microorganism composite system designed by the present invention is as follows:

[0056] C-BiOBr / MXene material is in situ grown on the anode 6 electrode exposed to the overlying water layer. When subjected to the mechanical energy of the water flow, the surface of this material will produce strain pressure, and the lattice deformation of the semiconductor is further converted into chemical energy. This can accelerate the photocatalytic removal of pollutants and can synergistically reduce heavy metal (Zn, Cu) ions, etc., reducing the toxicity of heavy metals.

[0057] In the C-BiOBr / MXene material, the piezoelectric BiOBr is modified by positively charged ions on the CND surface. The electrostatic adsorption between the materials makes the highly conductive two-dimensional material MXene with a negative surface tightly bonded to it, making it stable and not easy to decompose.

[0058] When natural light refracts and strikes the surface of the C-BiOBr / MXene material, it stimulates the separation of electron-hole pairs in the semiconductor. The holes then undergo an oxidation reaction in the underwater environment, generating hydroxyl radicals that contribute to the degradation of organic pollutants in the overlying subsurface. These organic pollutants decompose into various intermediate products, providing a carbon source for the growth and metabolism of microorganisms on the sediment surface and beneath the anode 6. These products are then mineralized into the final products, carbon dioxide and water.

[0059] The entire main body of the anode 6 is supported by an iron wire, which sways gently with the flow of overlying water without breaking easily. The C-BiOBr / MXene material is loaded onto the surface of the iron wire through an in-situ growth method, making it stable and strong, and suitable for multiple cycles.

[0060] Anode 6 extends downward to the bottom of the sediment, providing a growth, incubation, and attachment point for the underlying community of electroactive microorganisms, thereby enhancing biofilm growth at the bottom of anode 6. Electroactive bacteria / FeS hybrid material 9 is added to sediment layer 8. Conductive nanomaterials like FeS can address the low electron transfer efficiency caused by a thick biofilm at the bottom of the anode, as well as the high recombination efficiency of photogenerated electron-hole pairs and low photon efficiency that exist in single-phase photocatalysis.

[0061] Electrons are then transferred to the metal surface of the main material 7, using the electroactive bacteria's unique extracellular electron transfer pathway, and then to the anode 6, participating in the electronic circuit. Due to the microbial growth, a portion of the electroactive bacteria / FeS hybrid material 9 is exposed to the surface of the sediment layer 8, where it is illuminated by both natural light and underwater light source 10. The FeS stimulates photogenerated carriers under the action of light, generating active free radicals that participate in the degradation of pollutants at the solid-liquid interface. The underwater light source 10 enhances the light intensity lost to sunlight refraction at the overlying water bottom, accelerating pollutant removal.

[0062] The cathode 2 is made of high-performance polymer materials such as PVDF-HFP as the main frame and doped with La 1-x Ca x NiO3 forms a composite material; the structural design of this composite material can adjust the electronic structure, carrier concentration and oxygen vacancies of the material, thereby optimizing the performance of the material. 1-x Ca x NiO3 absorbs light energy, generating photogenerated electrons and holes. These photogenerated carriers migrate to the surface of the composite material on cathode 2, undergoing redox reactions with pollutant molecules adsorbed on the surface, thereby removing them. The introduction of PVDF is used to improve the surface properties of the material, increase the separation efficiency of photogenerated carriers, and enhance piezoelectric catalytic performance. As cathode 2, this part mainly undergoes reduction reactions. During the electrolysis of water, the composite material can catalyze the decomposition of water molecules, producing hydrogen and oxygen, while simultaneously removing pollutants from the water.

[0063] As wastewater flows through natural water bodies, it drives cathode 2, converting mechanical energy within the natural water into chemical energy. Organic matter is decomposed to produce electrons and protons. The electrons are received by anode 6 and transferred to the cathode via a wire and resistor, forming a circuit. The irregular movement of the protons in the overlying water reaches the cathode, where they react with the electrons and the oxygen contained in the overlying water to produce CO2 and H2O, generating an electric current and enhancing the treatment efficiency of solid-liquid two-phase composite pollutants. In sediment layer 8, extracellular electron transfer and electrical conduction between electroactive microorganisms and FeS, as well as piezoelectric photocatalytic degradation of pollutants, provide intermediate products for their digestion and metabolism, reducing the overall residual toxicity of pollutants in the solid-liquid system and improving the mineralization of pollutants, producing CO2 and H2O.

[0064] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A photo-electric-microorganism composite system, characterized in that: include: Anode, cathode, external resistor, underwater light source and electroactive bacteria / FeS hybrid material; The lower end of the anode is inserted into the sediment layer and the upper end extends to the overlying water layer; C-BiOBr / MXene material is in situ grown at the position where the anode is exposed in the overlying water layer; The cathode floats on the overlying water layer; the cathode is a piezoelectric photocatalytic film PVDF-HFP, which is loaded with La 1-x Ca x NiO3; The external resistor is connected to the anode and the cathode via a first wire; The underwater light source is set in the overlying water layer; The electroactive bacteria / FeS hybrid material is added into the sediment layer; the electroactive bacteria / FeS hybrid material includes electroactive bacteria and FeS.

2. The light-electricity-microorganism composite system according to claim 1, characterized in that: It also includes solar panels; the solar panels are placed externally above the overlying water layer, and are used to provide electricity for the underwater light source.

3. The light-electricity-microorganism composite system according to claim 1, characterized in that: The wavelength of the underwater light source is >300nm, and the power of the underwater light source is <60W.

4. The light-electricity-microorganism composite system according to claim 1, characterized in that: The main material of the anode is iron wire.

5. The light-electricity-microorganism composite system according to claim 1, characterized in that: The C-BiOBr / MXene material includes the highly conductive two-dimensional material MXene and BiOBr; the highly conductive two-dimensional material MXene and BiOBr are compounded together through electrostatic adsorption; and the BiOBr surface is modified by CND.

6. The light-electricity-microorganism composite system according to claim 1, characterized in that: The anodes include a plurality of anodes connected in series; stones are wound between adjacent anodes.

7. The light-electricity-microorganism composite system according to claim 1, characterized in that: The piezoelectric photocatalytic film PVDF-HFP is a porous electrode film made of a flexible polymer material polyvinylidene fluoride-hexafluoropropylene copolymer.

8. The light-electricity-microorganism composite system according to claim 7, characterized in that: The piezoelectric photocatalytic film PVDF-HFP is composed of the crystalline part of polyvinylidene fluoride and the amorphous part of hexafluoropropylene.

9. The light-electricity-microorganism composite system according to claim 1, characterized in that: The electroactive bacteria are Shewanella spp.

10. Use of the photo-electric-microorganism composite system according to any one of claims 1 to 9 in a water ecological restoration project.

Images