Synchronous capacity and carbon emission reduction method for sewage treatment based on microbial fuel cell

Abstract

The invention relates to the technical field of bioelectrochemistry, and discloses a synchronous energy production and carbon emission reduction method for sewage treatment based on a microbial fuel cell, which comprises the following steps: anaerobically decomposing pollutants by anode microorganisms, and producing electrons, protons and carbon dioxide; the electrons and the protons reach the cathode through the outer path and the membrane; the captured carbon dioxide is guided into a recirculation pipeline; according to the signal judgment mode, switching the cathode atmosphere and setting sound field parameters; in the high-power mode, oxygen-containing gas is introduced, the sound field is set to be in a first working state, and oxygen reduction is executed; in a carbon conversion mode, carbon dioxide is introduced, the sound field is set to be in a second working state, and carbon dioxide is reduced into chemicals; collecting and utilizing electric energy; and managing or separating and recovering the generated chemicals. According to external input signals such as power grid load or carbon transaction price, the high-power electricity generation mode and the in-situ carbon conversion mode are switched, so that real-time economic or environmental requirements are flexibly responded, and the operation flexibility and the overall economic value are improved.

Description

Technical Field

[0001] This invention relates to the field of bioelectrochemical technology, specifically to a method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells. Background Technology

[0002] Microbial fuel cells are bioelectrochemical systems that utilize the anaerobic metabolic activities of electrogenic microorganisms to directly convert the chemical energy of organic pollutants in wastewater into electrical energy. They provide a way to synergistically solve environmental pollution and energy demand. The microbial biofilm in the anode chamber can oxidize and decompose organic pollutants, releasing electrons, protons, and metabolic byproducts.

[0003] In traditional applications, the design goals of microbial fuel cells are typically singular and fixed. Most systems focus on maximizing electrical output, with the cathode reaction designed as an oxygen reduction reaction, utilizing air or oxygen as the final electron acceptor to combine with protons and electrons transported from the anode to produce water. In this classic operating mode, the system's only outputs are electrical energy and treated wastewater. The metabolic gases produced in the anode chamber, primarily carbon dioxide, are considered exhaust gases and are typically released directly into the atmosphere from the reactor.

[0004] However, existing microbial fuel cell wastewater treatment technologies directly discard the carbon dioxide generated by anode metabolism, resulting in a waste of carbon resources. These technologies lack flexibility and are difficult to dynamically adjust based on external economic conditions (such as peak-valley electricity prices or carbon trading prices), limiting overall economic efficiency. Furthermore, the accumulation of intermediate products in the catalytic cycle can easily lead to electrode passivation, thereby inhibiting power output. Therefore, this invention provides a method for simultaneous power generation and carbon emission reduction in wastewater treatment based on microbial fuel cells to address the shortcomings of existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells. This method solves the problems of existing microbial fuel cell technologies, which typically have a single function when treating wastewater and directly emit carbon dioxide, a byproduct of anode metabolism, resulting in the waste of carbon resources and potential environmental problems.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells, comprising the following steps:

[0007] S1. In the anode chamber, the organic pollutants in the wastewater are anaerobically oxidized and decomposed using an electrogenic microbial biofilm, simultaneously generating electrons, protons, and gaseous carbon dioxide.

[0008] S2. The generated electrons are transferred to the cathode through an external circuit, the generated protons are migrated to the cathode chamber through a proton exchange membrane, and the generated carbon dioxide gas is captured and introduced into the gas recirculation pipeline.

[0009] S3. Based on the external input signal, the control system determines the current target operating mode, and according to the determination result, switches the gas atmosphere of the cathode chamber and matches the working parameters of the set sound field generator.

[0010] S4. When it is determined that the current target operating mode is a high-power power generation mode, the cathode oxygen reduction co-operation step is executed, oxygen-containing gas is introduced into the cathode chamber, and the sound field generating device is set to the first working state. The liquid metal catalyst interface of the cathode undergoes chemical oxidation and electrochemical reduction cycle to complete the oxygen reduction reaction.

[0011] S5. When it is determined that the current target operating mode is the in-situ carbon conversion mode, the cathode carbon dioxide electroreduction coordinated operation step is executed, the carbon dioxide gas in the gas recirculation pipeline is introduced into the cathode chamber, and the sound field generating device is set to the second working state. The liquid metal catalyst of the cathode uses the electrons and protons to reduce the carbon dioxide into chemicals.

[0012] S6. Collect and utilize the electrical energy generated by the external circuit, and manage or separate and recycle the chemicals generated by the in-situ carbon conversion mode.

[0013] Preferably, in step S2, the gas recirculation pipeline includes a gas pipe with one end connected to the gas collection port of the anode chamber and the other end connected to the carbon dioxide recirculation inlet of the cathode chamber, and also includes a gas conveying power device for the controllable conveying of the carbon dioxide.

[0014] Preferably, in step S3, the external input signal includes at least one of the following: a power grid load signal, a carbon trading market price signal, or an internal sensor signal. The control system has a built-in preset mode judgment logic, which includes:

[0015] When the external input signal is higher than the preset power demand threshold, the target operating mode is determined to be the high-power power generation mode;

[0016] When the external input signal is lower than the preset power demand threshold or higher than the preset carbon conversion economic threshold, the target operating mode is determined to be the in-situ carbon conversion mode.

[0017] Preferably, the dynamic judgment and control steps of the target operating mode include:

[0018] When the high-power power generation mode is determined, the control system opens the air or oxygen inlet valve of the cathode chamber, closes the carbon dioxide recirculation inlet valve, and sets the sound field generator to enter the first working state.

[0019] When the in-situ carbon conversion mode is determined, the control system closes the air or oxygen inlet valve of the cathode chamber, opens the carbon dioxide recirculation inlet valve, starts the gas delivery power device, and sets the sound field generator to enter the second working state.

[0020] Preferably, in step S4, the chemical oxidation and electrochemical reduction cycle includes:

[0021] In the chemical oxidation step, a liquid metal catalyst reacts with an oxygen-containing gas to form a solid gallium oxide layer;

[0022] In the electrochemical reduction step, electrons and protons undergo an electrochemical reduction reaction at the interface of the solid gallium oxide layer, reducing gallium oxide to liquid metal.

[0023] Preferably, in step S4, the sound field generating device in the first working state applies periodic physical disturbances to the interface of the liquid metal catalyst to physically regulate the gallium oxide layer.

[0024] Preferably, in step S5, the step of performing the cathode carbon dioxide electroreduction coordinated operation further includes:

[0025] The control system closes the oxygen-containing gas inlet valve of the cathode chamber, opens the carbon dioxide recirculation inlet valve on the gas recirculation pipeline, and starts the gas delivery power unit.

[0026] The liquid metal catalyst is switched from an oxygen reduction catalyst to a carbon dioxide reduction catalyst, using electrons and protons transferred from the anode to reduce carbon dioxide to a chemical selected from formic acid or carbon monoxide.

[0027] Preferably, in step S5, the sound field generating device in the second working state applies ultrasonic waves to induce acoustic micro-convection at the interface of the liquid metal catalyst, thereby disrupting the diffusion boundary layer and enhancing the mass transfer process of carbon dioxide.

[0028] Preferably, in step S6, the step of managing or separating and recovering the chemicals generated by the in-situ carbon conversion mode further includes:

[0029] The electrical energy generated by the external circuit is monitored and allocated to drive the central control system, gas conveying power unit or sound field generating device, or to store the electrical energy in energy storage equipment or connect it to the external power grid.

[0030] When the aforementioned cathode carbon dioxide electroreduction synergistic operation step is performed, the generated chemicals are managed and separated:

[0031] When the chemical is a liquid product, the catholyte rich in the liquid product is discharged downstream for separation, including purification and recovery using distillation, liquid-liquid extraction, chromatographic separation, electrodialysis or nanofiltration membrane separation technology.

[0032] When the chemical contains gaseous products, the tail gas containing the gaseous products is separated and purified through a cathode tail gas collection pipeline to separate and enrich them.

[0033] Preferably, the liquid metal catalyst is a gallium-based liquid metal, specifically pure gallium or a gallium-indium alloy.

[0034] This invention provides a method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells. It offers the following advantages:

[0035] 1. By setting dynamic judgment and control steps for cathode operation mode, this invention can intelligently switch between high-power power generation mode and in-situ carbon conversion mode based on external input signals such as grid load or carbon trading price. This overcomes the limitation of the single function of traditional microbial fuel cells, thereby flexibly responding to real-time economic or environmental needs, optimizing the configuration of power generation and carbon resource utilization in the wastewater treatment process, and improving the system's operational flexibility and overall economic value.

[0036] 2. In the high-power power generation mode, this invention combines the chemical oxidation-electrochemical reduction cycle of liquid metal catalyst with the acoustic field of the first working state. The periodic physical disturbance applied by the acoustic field can actively regulate the gallium oxide layer generated at the cathode interface, effectively preventing electrode passivation caused by excessive oxide layer growth. It can also provide active anti-pollution function for the cathode, ensuring that the system can maintain high power density and long-term operational stability when treating complex wastewater environments.

[0037] 3. In the in-situ carbon conversion mode, the present invention utilizes the captured anode metabolic byproduct carbon dioxide as raw material and synergistically matches the acoustic field of the second working state to induce an acoustic micro-convection effect at the interface of the liquid metal catalyst. This effect greatly enhances the mass transfer rate of carbon dioxide reactants, effectively overcomes the mass transfer bottleneck caused by the low solubility of carbon dioxide in aqueous electrolytes, improves carbon conversion efficiency and chemical generation rate, and realizes the simultaneous removal and in-situ resource utilization of organic pollutants and carbon dioxide waste in wastewater. Attached Figure Description

[0038] Figure 1 This is a flowchart of the method steps of the present invention;

[0039] Figure 2 This is a flowchart of the dynamic judgment and control process for the cathode operating mode of the present invention;

[0040] Figure 3 This is a flowchart of the product management and separation process of the present invention. Detailed Implementation

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] See attached document Figure 1 , Figure 1 This is a schematic diagram of a method flow according to an embodiment of the present invention. The present invention provides a method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells, comprising the following steps:

[0043] S1 executes the anodic anaerobic metabolism and multiphase product generation steps. In the reactor anode chamber, the organic pollutants in the wastewater are anaerobically oxidized and decomposed using an electrogenic microbial biofilm. This process simultaneously generates electrons that enter the anode electrode, protons that enter the electrolyte, and gaseous carbon dioxide.

[0044] S2, performs the anode product separation and targeted transport steps. Electrons generated at the anode are transferred to the cathode via an external circuit, and protons are selectively migrated to the cathode chamber via a proton exchange membrane; simultaneously, carbon dioxide gas generated in the anode chamber is captured and introduced into the gas recirculation pipeline.

[0045] S3 executes the dynamic judgment and control steps for the cathode operating mode. The control system determines the current target operating mode of the system based on external input signals. Based on the judgment result, the control system switches the gas atmosphere in the cathode chamber and matches the operating parameters of the set sound field generator.

[0046] S4, when the high-power power generation mode is determined, the cathode oxygen reduction coordinated operation step is executed. Oxygen-containing gas is introduced into the cathode chamber, and the acoustic field device is set to the first working state. The liquid metal interface of the cathode undergoes a chemical oxidation and electrochemical reduction cycle to complete the oxygen reduction reaction. The acoustic field in the first working state physically regulates the oxide layer generated at the interface and achieves active pollution prevention.

[0047] S5, when the in-situ carbon conversion mode is determined, the cathode carbon dioxide electroreduction synergistic operation step is executed, the captured carbon dioxide gas is introduced into the cathode chamber, and the acoustic field device is set to the second working state. The liquid metal catalyst of the cathode uses the electrons and protons transferred from the anode to reduce carbon dioxide into chemicals. The acoustic field in the second working state induces acoustic micro-convection at the catalyst interface to enhance the mass transfer process of carbon dioxide.

[0048] S6, executes system product management and separation steps. It collects and utilizes electrical energy generated by the external circuitry, and during in-situ carbon conversion mode operation, exports and separates / recovers liquid chemicals generated in the cathode chamber electrolyte.

[0049] In this embodiment, the steps of S1 for performing anodic anaerobic metabolism and multiphase product generation include:

[0050] An anode chamber is provided for hosting microorganisms and collecting electrons from an anode electrode, preferably a material with good conductivity, biocompatibility, and a large specific surface area. In some embodiments, the anode electrode is a three-dimensional porous material, specifically including but not limited to carbon felt, carbon brush, graphite particles, graphite foam, or carbon nanotube composite materials.

[0051] The anode chamber is inoculated with a source of bacteria rich in electrogenic microorganisms, which are derived from anaerobic digested sludge, natural water sediments, or effluent from a stable microbial electrochemical system. By supplying specific substrates (such as sodium acetate, glucose, etc.) under anaerobic conditions, the electrogenic microorganisms are enriched and colonized on the surface of the anode electrode, forming an electrochemically active biofilm.

[0052] After the electroactive biofilm is stably formed, wastewater containing organic pollutants is continuously or intermittently pumped into the anode chamber as a substrate. The organic pollutants (substrate) can be biodegradable components in domestic sewage, agricultural and livestock wastewater, food processing wastewater, or specific chemical substrates.

[0053] The anode chamber maintains an anaerobic environment, and the electrogenic microorganisms in the electroactive biofilm decompose the organic pollutants (in general chemical formulas) (Indicated) as an electron donor in anaerobic oxidative metabolism, during which microorganisms utilize the anolyte as their final electron acceptor. This process converts the chemical energy of pollutants in wastewater into electrical energy, protons, and metabolic gases, and its reaction (indicated by) The stoichiometric relationships (taking one example) are shown below:

[0054] ;

[0055] in, General chemical formulas representing organic substrates in wastewater; , and These represent the molar numbers of carbon, hydrogen, and oxygen atoms in an organic substrate molecule, respectively. This represents protons produced by metabolism, which are released into the liquid phase (anolyte) of the anode chamber; This represents electrons produced by metabolism, which are released by electrogenic microorganisms and transferred to the anode electrode.

[0056] generated electrons The protons generated are collected by the conductive substrate of the anode electrode, becoming the current source for the external circuit; The ion stream enters the anolyte, forming an ion flow; the generated carbon dioxide, as an insoluble gas, escapes from the liquid phase and collects in the top gas phase space of the anode chamber. This step is crucial for subsequent energy extraction, proton transmembrane transport, and... In-situ transformation provides their own independent material basis.

[0057] In this embodiment, the S2 step of performing anolyte product separation and targeted transport includes:

[0058] Through the electrons generated at the anode proton and carbon dioxide To achieve effective separation and direct them to their respective reaction or utilization pathways, electrons collected by the anode electrode... Electrons are drawn from the anode electrode through an external circuit located outside the reactor. This external circuit electrically connects the anode and cathode electrodes. Electrons migrate directionally to the cathode within this external circuit, forming the system's operating current. The external circuit may be equipped with a load (e.g., an external resistor), a power management system (PMS), or a potentiostat for electrochemical testing and control, as needed.

[0059] Protons released into the anolyte The ions are separated and transported via an ion-conducting membrane disposed between the anode and cathode chambers. In a preferred embodiment, the ion-conducting membrane is a proton exchange membrane (PEM), such as a perfluorosulfonic acid type ion exchange membrane. Driven by an electrochemical potential gradient (combining concentration and potential gradients), the protons selectively cross the proton exchange membrane, migrating from the anolyte chamber to the cathode chamber. This process physically blocks the anolyte substrate from contacting the cathode oxidant (or...). Simultaneously with contact, the ion circuit is closed, and the necessary reactants are provided for the cathodic electrochemical reduction reaction (i.e., oxygen reduction reaction or carbon dioxide reduction reaction). .

[0060] The metabolic gases (mainly carbon dioxide) collected in the gas phase space at the top of the anode chamber are... The gas is actively captured and targeted transported through a gas collection port located on the anode chamber. This embodiment includes a gas recirculation pipeline system, which specifically comprises gas pipes, controlled valves, and a gas delivery power unit. The gas delivery power unit is used to achieve… An active, controllable delivery actuator, such as a miniature air pump, diaphragm pump, or blower. One end of the gas recirculation pipeline system is connected to the gas collection port of the anode chamber, and the other end is connected to the dedicated gas inlet of the cathode chamber, namely the carbon dioxide recirculation inlet. .

[0061] The gas recirculation pipeline system (particularly its controlled valves and gas delivery power unit) is connected to the central control system. When the central control system determines that the system needs to perform in-situ carbon conversion, it will activate the gas delivery power unit and transfer the gas generated at the anode. The gas is controlled and delivered to the cathode chamber as feedstock via a gas recirculation pipeline system to remove anode metabolic byproducts. It is transformed into an internal cycle and in-situ resource utilization of cathode reaction raw materials.

[0062] See attached document Figure 2 In this embodiment, the dynamic judgment and control steps of S3 for the cathode operating mode include:

[0063] The central control system is a programmable logic controller (PLC), microcontroller (MCU), embedded system, or computer workstation running a specific control algorithm. The central control system is electrically or signal-connected to the gas inlet control valve, gas recirculation pipeline system, and cathode acoustic field generator of the cathode chamber to execute subsequent judgment and control commands.

[0064] The central control system Receive external input signals in real time or periodically. The external input signal serves as the basis for determining the system's operational mode. In one embodiment, the external input signal may be a power grid load signal, which indicates the current peak-valley status of the power grid or the real-time electricity price. In another embodiment, the external input signal may be a carbon trading market price signal, which indicates the current economic value of carbon emission reduction. In yet another embodiment, the external input signal is an internal sensor signal, such as the reading of the anode chamber COD (chemical oxygen demand) sensor or the anode potential, used to represent the metabolic load of the anode.

[0065] The central control system has a built-in preset mode judgment logic, which is based on the received signal. Make decisions. For example, when (e.g., the power grid load signal) is higher than the preset power demand threshold. When the system determines that the current objective is "high-power power generation," it decides to execute the cathode oxygen reduction (ORR) coordinated operation steps. Below ,or (Such as carbon price signals) exceeding a preset carbon conversion economic threshold When the system determines that the current objective is "in-situ carbon conversion", it decides to execute the cathode carbon dioxide electroreduction (CO2RR) co-operation step.

[0066] Central control system Based on the decision result, the switching control of the cathode gas atmosphere is executed. If the decision is to execute the cathode oxygen reduction (ORR) coordinated operation step, the central control system sends a command to open the air / oxygen inlet valve of the cathode chamber, allowing oxygen-containing gas to flow at a set rate. Turn on the gas, close the carbon dioxide recirculation inlet valve on the gas recirculation pipeline, and stop the gas delivery power unit.

[0067] If the decision is to execute the cathode carbon dioxide electroreduction (CO2RR) coordinated operation step, the central control system sends a command to close the air / oxygen inlet valve and stop the supply of oxygen-containing gas; simultaneously, it opens the carbon dioxide recirculation inlet valve and starts the gas delivery power device (such as an air pump) to transfer the gas captured at the anode. Gas at a set flow rate Actively pumped into the cathode chamber.

[0068] While performing gas atmosphere switching, the central control system simultaneously regulates the sound field generating device (such as a piezoelectric ceramic transducer) located in the cathode chamber to match its operating parameters with the currently selected operating mode.

[0069] If the decision is to execute the cathode oxygen reduction (ORR) coordinated operation step, the central control system sets the sound field generating device to enter the "first working state". The parameters of the "first working state" are designed to physically regulate and actively prevent fouling of the oxide layer at the cathode interface. Its characteristic parameters include specific frequencies used to generate mechanical vibrations or macroscopic acoustic flows. (e.g., in the low frequency or audio range of 10Hz to 10kHz) and the corresponding first sound field power .

[0070] If the decision is to execute the cathode carbon dioxide electroreduction (CO2RR) coordinated operation step, the central control system sets the sound field generating device to enter the "second operating state". The parameters of the "second operating state" are designed to achieve... Mass transfer enhancement. Its characteristic parameters include specific frequencies used to induce strong acoustic microstreaming at the catalyst interface. (e.g., in the ultrasonic frequency band from 20kHz to 2MHz) and the corresponding second sound field power .

[0071] cathode reaction atmosphere or With cathode physical field ( or Coordination, matching, and synchronization switching between ( ).

[0072] In this embodiment, when the system target is determined to be a high-power power generation mode, S4 executes the cathode oxygen reduction (ORR) coordinated operation steps, including:

[0073] The control system provides oxygen-containing gas to the cathode chamber. Introduce oxygen-containing gas (such as air, oxygen-enriched air, or pure oxygen) at a preset flow rate. To maintain the supply, the control system synchronously activates the sound field generator located in the cathode chamber and puts it into a preset "first working state." This "first working state" has specific sound field parameters ( , The aim is to achieve physical control and active antifouling of the cathode interface.

[0074] In this embodiment, the cathode uses gallium-based liquid metal (LM) as a catalyst. In a specific embodiment, the liquid metal can be pure gallium. Or gallium with other metals (such as indium) ,tin The liquid metal is formed as a binary or multi-element alloy (e.g., gallium-indium alloy EGaIn). The liquid metal is coated or loaded onto the conductive substrate of the cathode (e.g., a gas diffusion layer) in the form of a thin film or droplet array.

[0075] In this mode, the oxygen reduction reaction (ORR) at the cathode proceeds through a highly efficient "chemical oxidation-electrochemical reduction" cycle mechanism, which differs from the direct oxygen reduction pathway on traditional cathode catalysts (such as platinum-carbon). Specifically:

[0076] The chemical oxidation step of the cycle mechanism is as follows: the introduced oxygen In liquid metal (with) For example, a rapid, spontaneous chemical reaction occurs on the surface, forming solid gallium oxide. The reaction formula for the "skin" or oxide layer is as follows:

[0077] ;

[0078] The electrochemical reduction step of the cycle mechanism is as follows: electrons transferred from the anode and protons In the solid An electrochemical reduction reaction occurs at the oxide layer interface. This reaction will... Reduced to liquid state At the same time, water is generated. This allows the liquid metal catalyst to be regenerated. The reaction formula is as follows:

[0079] ;

[0080] Through a continuous cycle of two steps—chemical oxidation and electrochemical reduction—it was achieved that... Net consumption and The generation of oxygen completes the overall oxygen reduction reaction and drives the flow of electrons in the external circuit to generate electrical energy.

[0081] The "first working state" sound field at startup, during the chemical oxidation step, if Oxide layer If the growth is too rapid or too thick, its poor conductivity will lead to increased electrode polarization, which will hinder the kinetics of the electrochemical reduction step, i.e., "electrode passivation", and thus reduce the overall reaction rate and power output.

[0082] The sound field of the "first working state" ( , The specific implementation method is low-frequency mechanical vibration (e.g., to (or a specific mode of acoustic flow) applies periodic physical perturbations to the interface of a liquid metal catalyst, the physical perturbations actively causing excessive thickness... The oxide layer may develop microcracks, peel off, or destabilize, or it may be maintained at an optimal thickness that facilitates electron and proton transport. This synergistic regulation of "mechanical force and electrochemistry" ensures that the cycles of chemical oxidation and electrochemical reduction are always in a highly efficient dynamic balance, effectively preventing electrode passivation.

[0083] The sound field in the "first working state" also provides an active anti-pollution function. In the wastewater treatment environment, the cathode surface is easily contaminated by biofilm or suspended pollutants, which leads to a decrease in catalytic activity. The physical vibration and acoustic flow generated by the sound field provide a wide range of mechanical disturbances in the cathode chamber (including the liquid metal surface and structural dead corners).

[0084] This mechanical disturbance can physically peel off contaminants (such as biofilms) in the early stages of their adhesion (i.e. when the adhesion is weakest), preventing further growth and accumulation. This enhances the long-term operational stability of the cathode in complex wastewater environments and ensures the continuous operation of high-power generation.

[0085] In this embodiment, when the system target is determined to be in-situ carbon conversion mode, S5 executes the cathode carbon dioxide electroreduction (CO2RR) coordinated operation step, which includes:

[0086] The control system shuts off the oxygen-containing gas inlet to the cathode chamber. The valve stops the supply of oxygen or air; at the same time, the control system opens the carbon dioxide recirculation inlet valve on the gas recirculation pipeline and starts the gas delivery power device (such as a micro air pump).

[0087] After the gas delivery power unit is activated, the captured anode will be... The gas, used as the feedstock, flows at a preset gas flow rate. It is actively and controllably transported to the cathode chamber, so that it comes into contact with the liquid metal catalyst of the cathode.

[0088] While performing the gas atmosphere switching, the control system also activates the sound field generator located in the cathode chamber and puts it into a preset "second working state." This "second working state" has specific sound field parameters ( , ), aiming to achieve Physical enhancement of reactant mass transfer processes.

[0089] In this mode, the liquid metal (LM, such as Alternatively, an EGaIn alloy catalyst can be used, switching from an oxygen reduction (ORR) catalyst to a carbon dioxide reduction (CO2RR) catalyst. The liquid metal catalyst utilizes electrons transferred from the anode. and protons For supply An electrochemical reduction is performed. The reaction products of the CO2RR depend on the composition of the liquid metal catalyst and the operating potential of the cathode. In some embodiments, the reduction reaction primarily produces high-value-added C1 chemicals, such as formic acid. or carbon monoxide The corresponding electrochemical reaction formula can be:

[0090] ;

[0091] or

[0092] ;

[0093] When CO2RR is carried out in an aqueous electrolyte, its The low solubility of gases in the electrolyte leads to a slow mass transport rate at the catalyst-electrolyte interface, resulting in the formation of a thick diffusion boundary layer on the catalyst surface. Flux to catalytically active sites This limitation restricts the overall carbon conversion reaction rate.

[0094] The activated "second working state" sound field is an ultrasonic wave of a specific frequency. (e.g., in the ultrasonic frequency band from 20kHz to 2MHz) and the corresponding acoustic power The ultrasound induces a strong "acoustic microstreaming" effect at the liquid metal-electrolyte interface. Acoustic microstreaming is a high-speed, small-scale steady-state eddy current generated near the interface under the drive of the acoustic field.

[0095] The sono-induced microconvection provides intense local hydrodynamic disturbances to perform in-situ micro-stirring on the catalyst surface, thereby significantly disrupting and thinning the diffusion boundary layer and releasing dissolved electrolytes from the bulk electrolyte. Molecules are "pumped" at high speed to the active surface of the liquid metal catalyst.

[0096] Through the sound field mass transfer enhancement mechanism. The reactant supply rate is enhanced. This synergistic effect of "physical field-enhanced mass transfer" and the "electrochemical catalysis" of the liquid metal catalyst ensures that the CO2RR reaction rate is no longer limited by slow physical diffusion, thus improving the overall carbon conversion efficiency and chemical efficiency (such as...) of the system. The generation rate is improved.

[0097] See attached document Figure 3 In this embodiment, the S6 execution system product management and separation steps include:

[0098] The electrical energy products generated in the external circuit are managed, wherein the electrical energy products are the current continuously output by the external circuit in two operating modes: cathode oxygen reduction (ORR) synergistic operation and cathode carbon dioxide electroreduction (CO2RR) synergistic operation. and voltage .

[0099] In some embodiments, the management of the electrical energy products is achieved through a Power Management System (PMS), which can manage the output power (…). Monitoring and allocation are carried out. Specific utilization methods include:

[0100] Electrical energy is used to drive auxiliary components required for the operation of this system, such as the central control system, the gas delivery power unit (e.g., an air pump), and the sound field generator. ;

[0101] Electrical energy is stored in energy storage devices (such as batteries or supercapacitors);

[0102] It is connected to the external power grid.

[0103] When the system performs the cathode carbon dioxide electroreduction (CO2RR) co-operation step, the chemical conversion products generated in the cathode chamber are managed and separated. These chemical conversion products are those obtained by... The specific chemicals produced by reduction.

[0104] If the chemical conversion product is a liquid product, the product will dissolve and accumulate in the liquid electrolyte (catholytic liquid) in the cathode chamber. The catholytic liquid rich in the liquid product will be continuously or periodically discharged through the effluent outlet provided in the cathode chamber.

[0105] The discharged catholy solution is transported to a downstream product separation unit, which separates the product according to its composition (e.g., ...). The physicochemical properties of the product separation unit are considered, and the specific implementation of the product separation unit includes, but is not limited to, distillation (e.g., extractive distillation or azeotropic distillation), liquid-liquid extraction, chromatographic separation, electrodialysis, or nanofiltration membrane separation technology, in order to purify and recover the target chemical from the catholyte.

[0106] If the chemical conversion product contains a gaseous product (e.g., generated carbon monoxide), the gaseous product will escape from the catholyte and be discharged along with the tail gas of the cathode chamber. By setting up a cathode tail gas collection pipeline, this mixed gas is led to a gas separation and purification unit (e.g., pressure swing adsorption or membrane separation device) to separate and enrich the gaseous chemical product for use.

[0107] The purified water generated by the cathode oxygen reduction (ORR) co-operation step and the by-product water generated by the cathode carbon dioxide electroreduction (CO2RR) co-operation step are both collected in the catholyte. The total water balance of the system can be managed by exporting the catholyte, or in a specific embodiment, the purified water can be recycled.

[0108] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells, characterized in that, Includes the following steps: S1. In the anode chamber, the organic pollutants in the wastewater are anaerobically oxidized and decomposed using an electrogenic microbial biofilm, simultaneously generating electrons, protons, and gaseous carbon dioxide. S2. The generated electrons are transferred to the cathode through an external circuit, the generated protons are migrated to the cathode chamber through a proton exchange membrane, and the generated carbon dioxide gas is captured and introduced into the gas recirculation pipeline. S3. Based on the external input signal, the control system determines the current target operating mode, and according to the determination result, switches the gas atmosphere of the cathode chamber and matches the working parameters of the set sound field generator. S4. When it is determined that the current target operating mode is a high-power power generation mode, the cathode oxygen reduction coordinated operation step is executed, oxygen-containing gas is introduced into the cathode chamber, and the sound field generating device is set to the first working state. The liquid metal catalyst interface of the cathode undergoes chemical oxidation and electrochemical reduction cycle to complete the oxygen reduction reaction. S5. When it is determined that the current target operating mode is the in-situ carbon conversion mode, the cathode carbon dioxide electroreduction coordinated operation step is executed, the carbon dioxide gas in the gas recirculation pipeline is introduced into the cathode chamber, and the sound field generating device is set to the second working state. The liquid metal catalyst of the cathode uses electrons and protons to reduce carbon dioxide into chemicals. S6. Collect and utilize the electrical energy generated by the external circuit, and manage or separate and recycle the chemicals generated by the in-situ carbon conversion mode.

2. The method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells according to claim 1, characterized in that, In step S2, the gas recirculation pipeline includes a gas pipe with one end connected to the gas collection port of the anode chamber and the other end connected to the carbon dioxide recirculation inlet of the cathode chamber, and also includes a gas conveying power device for the controllable conveying of the carbon dioxide.

3. The method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells according to claim 1, characterized in that, In step S3, the external input signal includes at least one of the following: grid load signal, carbon trading market price signal, or internal sensor signal. The control system has a built-in preset mode judgment logic, which includes: When the external input signal is higher than the preset power demand threshold, the target operating mode is determined to be the high-power power generation mode; When the external input signal is lower than the preset power demand threshold or higher than the preset carbon conversion economic threshold, the target operating mode is determined to be the in-situ carbon conversion mode.

4. The method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells according to claim 3, characterized in that, The dynamic judgment and control steps for the target operating mode include: When the high-power power generation mode is determined, the control system opens the air or oxygen inlet valve of the cathode chamber, closes the carbon dioxide recirculation inlet valve, and sets the sound field generator to enter the first working state. When the in-situ carbon conversion mode is determined, the control system closes the air or oxygen inlet valve of the cathode chamber, opens the carbon dioxide recirculation inlet valve, starts the gas delivery power device, and sets the sound field generator to enter the second working state.

5. The method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells according to claim 1, characterized in that, In step S4, the chemical oxidation and electrochemical reduction cycle includes: In the chemical oxidation step, a liquid metal catalyst reacts with an oxygen-containing gas to form a solid gallium oxide layer; In the electrochemical reduction step, electrons and protons undergo an electrochemical reduction reaction at the interface of the solid gallium oxide layer, reducing gallium oxide to liquid metal.

6. The method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells according to claim 1, characterized in that, In step S4, the sound field generating device in the first working state applies periodic physical perturbations to the interface of the liquid metal catalyst to physically regulate the gallium oxide layer.

7. The method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells according to claim 1, characterized in that, In step S5, the step of performing the cathode carbon dioxide electroreduction coordinated operation further includes: The control system closes the oxygen-containing gas inlet valve of the cathode chamber, opens the carbon dioxide recirculation inlet valve on the gas recirculation pipeline, and starts the gas delivery power unit. The liquid metal catalyst is switched from an oxygen reduction catalyst to a carbon dioxide reduction catalyst, using electrons and protons transferred from the anode to reduce carbon dioxide to a chemical selected from formic acid or carbon monoxide.

8. The method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells according to claim 1, characterized in that, In step S5, the sound field generating device in the second working state applies ultrasonic waves to induce acoustic micro-convection at the interface of the liquid metal catalyst, thereby disrupting the diffusion boundary layer and enhancing the mass transfer process of carbon dioxide.

9. The method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells according to claim 1, characterized in that, In step S6, the step of managing or separating and recovering the chemicals generated by the in-situ carbon conversion mode further includes: The electrical energy generated by the external circuit is monitored and allocated to drive the central control system, gas conveying power unit or sound field generating device, or to store the electrical energy in energy storage equipment or connect it to the external power grid. When the aforementioned cathode carbon dioxide electroreduction synergistic operation step is performed, the generated chemicals are managed and separated: When the chemical is a liquid product, the catholyte rich in the liquid product is discharged downstream for separation, including purification and recovery using distillation, liquid-liquid extraction, chromatographic separation, electrodialysis or nanofiltration membrane separation technology. When the chemical contains gaseous products, the tail gas containing the gaseous products is separated and purified through a cathode tail gas collection pipeline to separate and enrich them.

10. The method for simultaneous energy production and carbon emission reduction in wastewater treatment based on microbial fuel cells according to claim 1, characterized in that, The liquid metal catalyst is a gallium-based liquid metal, specifically pure gallium or a gallium-indium alloy.

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