Self-separation type device for preparing ammonia from nitrate based on photoelectric coupling and cathode confinement
The self-separating nitrate ammonia production device using photoelectric coupling and the cathode limiting domain solves the problem of insufficient integrated catalysis-separation design in existing technologies, achieving low-energy ammonia preparation and efficient separation, and is suitable for engineering applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HENAN NORMAL UNIV
- Filing Date
- 2026-01-16
- Publication Date
- 2026-04-24
AI Technical Summary
In existing technologies, electrocatalytic nitrate reduction ammonia production devices lack an integrated catalysis-separation design, which makes it difficult to obtain ammonia products directly, increases energy consumption and cost, and lacks a modular system that is easy to maintain.
A self-separating nitrate ammonia production device employing photoelectric coupling and cathodic limiting domain achieves in-situ self-separation and efficient preparation of ammonia by creating a local alkaline environment near the catalyst electrode, combined with a transparent reaction chamber, ultrasonic liquid level detection, and an adjustable circulation path. The modular design facilitates catalyst installation and maintenance.
This invention integrates low-energy nitrate reduction for ammonia production and ammonia separation, reducing alkali consumption and equipment investment, improving ammonia production efficiency and selectivity, and featuring a compact structure suitable for engineering scale-up.
Smart Images
Figure CN121915431A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical catalysis and resource utilization of nitrogen-containing wastewater, specifically to a self-separating nitrate ammonia production device based on photoelectric coupling and the cathodic limit domain. Background Technology
[0002] Nitrates are widely present in industrial wastewater and agricultural water. Their excessive presence can lead to eutrophication and disrupt the ecological balance of water bodies. They can also be converted into nitrites and nitrosamines in organisms, posing a dual threat to the environment and human health. Therefore, efficient removal and resource utilization are of great significance. Electrocatalytic nitrate reduction to ammonia technology is a green technology that can simultaneously achieve pollution control and resource recovery. Its core advantage is that it can use renewable electricity to directly convert nitrate pollutants widely present in water bodies into valuable ammonia at normal temperature and pressure. This not only provides a low-carbon pathway for ammonia synthesis but also realizes the high-value recycling of nitrogen (Nature Catalysis, 2023, 6(5); Nature Communications, 2023, 14(1); Nature Communications, 2025, 16(1)).
[0003] Currently, the ammonia produced by the reaction is mainly dissolved in the electrolyte in the form of ammonium ions, which is difficult to obtain directly. It relies on subsequent additional separation steps such as adding alkali and heating, which increases energy consumption and cost. Moreover, most of the work still focuses on the catalytic process and lacks a systematic design for the integration of "catalysis-separation", which makes it difficult to apply in practice. (Nature Catalysis, 2019, 2(4); Nature Chemical Engineering, 2025, 2(7)).
[0004] Currently, there is a lack of a device for electrocatalytic reduction of nitrate to produce ammonia that can achieve in-situ self-separation of ammonia. Therefore, there is an urgent need to develop a new device to achieve the integration of "catalysis-separation" and promote the practical application of this technology. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to overcome the existing defects and provide a self-separating nitrate ammonia production device based on photoelectric coupling and cathode limit domain. This device achieves low-energy integrated production of ammonia from nitrate reduction and continuous separation of products. In addition, the modular design takes into account the engineering convenience brought about by catalyst maintenance, which can effectively solve the problems in the background technology.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain, comprising a cathode assembly, a diaphragm assembly, and an anode assembly arranged vertically from top to bottom. The cathode assembly includes an upper transparent reaction chamber, with a sealing cover plate at the upper end of the upper transparent reaction chamber to seal its upper end. An ammonia outlet pipe and an ultrasonic liquid level detector are provided on the sealing cover plate. An air inlet pipe, a nitrate wastewater inlet pipe, and a nitrate wastewater outlet pipe are provided on the side wall of the upper transparent reaction chamber. An upper conductive elastic fixing ring is provided inside the upper transparent reaction chamber, which fixes the catalyst to the upper side of the diaphragm assembly. An upper external metal electrode is connected to a metal groove on the upper transparent reaction chamber, with one end of the upper external metal electrode penetrating and extending to the outside of the upper transparent reaction chamber.
[0007] The anode assembly includes a lower transparent reaction chamber, inside which a lower conductive elastic fixing ring is provided. A lower external metal electrode is connected to a metal groove on the lower transparent reaction chamber. One end of the lower external metal electrode passes through and extends to the outside of the lower transparent reaction chamber. A counter electrode is provided inside the lower transparent reaction chamber and is fixed to the lower end of the lower transparent reaction chamber by the lower conductive elastic fixing ring. An upper water inlet pipe and a lower water outlet pipe are provided on the side wall of the lower transparent reaction chamber. The upper water inlet pipe and the lower water outlet pipe are located at the upper end and the lower end of the lower transparent reaction chamber, respectively. The upper water inlet pipe and the lower water outlet pipe are connected by a peristaltic pump pipeline to form a circulation path.
[0008] The membrane assembly includes an annular baffle, a cation exchange membrane, and a connecting layer. The connecting layer is embedded and connected to the upper transparent reaction chamber and the lower transparent reaction chamber. The upper side of the connecting layer is provided with an upper connecting layer groove that connects to the upper transparent reaction chamber. The upper connecting layer groove and the upper transparent reaction chamber cooperate to fix the cation exchange membrane. An annular baffle is provided between the fixed cation exchange membrane and the catalyst. The lower side of the connecting layer is also provided with a lower connecting layer groove that is sealed and connected to the lower transparent reaction chamber.
[0009] Furthermore, a handle is provided on the upper surface of the sealing cover.
[0010] Furthermore, the lower transparent reaction chamber and the upper transparent reaction chamber have the same structure. Both the lower transparent reaction chamber and the upper transparent reaction chamber include a cylindrical connecting shell. The inner side of the cylindrical connecting shell is provided with an annular groove. The inside of the annular groove is provided with a plastic groove. The inside of the plastic groove is provided with a metal groove. The cross-section of the plastic groove and the metal groove is an arc-shaped structure. The inner sides of the two metal grooves are respectively fixedly connected to the upper conductive elastic fixing ring and the lower conductive elastic fixing ring.
[0011] Furthermore, the upper and lower conductive elastic fixing rings have the same structure, and both are non-completely closed ring structures to facilitate installation, replacement, and disassembly. Both the upper and lower conductive elastic fixing rings have a three-spoke support structure built on top of the conductive elastic fixing ring. The conductive elastic fixing ring has a notch, and the three-spoke support structure built on top of the conductive elastic fixing ring is an integral unit. The upper and lower conductive elastic fixing rings are made of elastic metal material.
[0012] Furthermore, the conductive elastic fixing ring on the upper side is tightly attached to the catalyst, and the conductive elastic fixing ring on the upper side elastically presses and fixes the catalyst in the circumferential direction. While the conductive elastic fixing ring presses the catalyst, it allows the catalyst to be removed or replaced when needed.
[0013] Furthermore, the metal groove and the upper or lower conductive elastic fixing ring form an electrode substrate, and the catalyst forms a working electrode with the metal groove through a conductive connection. The conductive connection can be a press-fit, conductive adhesive bonding or conductive clamp connection to ensure low contact resistance and reconfigurable assembly.
[0014] Furthermore, the ultrasonic liquid level detector is electrically connected to an external control system. The ultrasonic liquid level detector is used to detect changes in the liquid level in the upper transparent reaction chamber in real time and to provide feedback to control the inlet flow rate of nitrate wastewater and the speed of the peristaltic pump. The external control system sets an upper limit threshold for the liquid level and links the inlet solenoid valve, the start / stop of the peristaltic pump, and its speed.
[0015] Furthermore, the inlet pipe on the upper transparent reaction chamber is used to introduce an inert gas or carrier gas, thereby carrying the ammonia gas escaping from the liquid phase to the ammonia outlet pipe for discharge and collection, and the carrier gas can be nitrogen, argon or air.
[0016] Furthermore, the cation exchange membrane is used for the liquid between the lower and upper transparent reaction chambers, allowing cation migration. The cation exchange membrane provides an ion conduction channel between the two chambers, reducing cross-contamination; synergistically with the localized high pH at the cathode, it allows NH4+ to... ⁺ The equilibrium shifts towards NH3, causing ammonia to escape in gaseous form.
[0017] Compared with existing technologies, the beneficial effects of this invention are as follows: by constructing a local alkaline environment near the catalyst electrode, rather than raising the overall pH of the system, alkali consumption is significantly reduced, and the selectivity and efficiency of nitrate reduction to ammonia production are improved; the integrated design of electrocatalytic reduction and ammonia self-separation enables in-situ removal of ammonia during the generation process, simplifying the process flow and reducing energy consumption and equipment investment; the "three-layer groove + notched conductive elastic fixing ring" structure ensures reliable catalyst fixation and facilitates quick installation, replacement, and maintenance; the integrated metal groove current collection significantly reduces contact resistance and ensures uniform current distribution; the diaphragm and clamping structure provide reliable sealing, reducing bypass flow and cross-contamination, and improving ammonia separation efficiency; the transparent reaction chamber facilitates observation and the introduction of light, and is compatible with photoelectric coupling to enhance the reaction; the transparent reaction chamber, ultrasonic liquid level detection, and adjustable circulation path facilitate process monitoring and automatic control, reduce concentration polarization, and the device has a compact structure and high degree of modularity, making it suitable for engineering scale-up and application promotion. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the structure of the present invention;
[0019] Figure 2 This is a top view schematic diagram of the conductive elastic fixing ring of the present invention;
[0020] Figure 3 This is a schematic diagram of the connection between the metal groove and the metal conductor of the present invention;
[0021] Figure 4 This is a top view schematic diagram of the three-layer groove and transparent reaction chamber structure of the present invention;
[0022] Figure 5 This is a schematic cross-sectional view of the three-layer groove and transparent reaction chamber structure of the present invention;
[0023] Figure 6 This is a top view of the connecting layer of the present invention.
[0024] In the diagram: 1. Ultrasonic liquid level detector; 2. Handle; 3. Ammonia outlet pipe; 3'. Inlet pipe; 4. Sealing cover; 5. Upper transparent reaction chamber; 5'. Lower transparent reaction chamber; 6. Nitrate wastewater outlet pipe; 6'. Nitrate wastewater inlet pipe; 7. Upper external metal electrode; 7'. Lower external metal electrode; 8. Upper conductive elastic fixing ring; 8'. Lower conductive elastic fixing ring; 9. Catalyst; 10. Circular baffle; 11. Cation exchange membrane; 12. Connecting layer; 121. Upper connecting layer groove; 122. Lower connecting layer groove; 13. Pair of electrodes; 14. Upper water inlet pipe; 14'. Lower water outlet pipe; 15. Plastic groove; 16. Metal groove. Detailed Implementation
[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] Please see Figure 1-6 This invention provides a technical solution: a self-separating nitrate ammonia production device based on photoelectric coupling and cathode limit domain, comprising a cathode assembly, a diaphragm assembly, and an anode assembly arranged vertically from top to bottom. The cathode assembly includes an upper transparent reaction chamber 5, with a sealing cover 4 at the upper end of the upper transparent reaction chamber 5 to seal its upper end. The sealing cover 4 is provided with an ammonia outlet pipe 3 and an ultrasonic liquid level detector 1. An air inlet pipe 3', a nitrate wastewater inlet pipe 6', and a nitrate wastewater outlet pipe 6 are provided on the side wall of the upper transparent reaction chamber 5. An upper conductive elastic fixing ring 8 is provided inside the upper transparent reaction chamber 5, which fixes the catalyst 9 to the upper side of the diaphragm assembly. A metal groove 16 on the upper transparent reaction chamber 5 is connected to an upper external metal electrode 7, one end of which penetrates and extends to the outside of the upper transparent reaction chamber 5.
[0027] The anode assembly includes a lower transparent reaction chamber 5′, inside which a lower conductive elastic fixing ring 8′ is provided. A lower external metal electrode 7′ is connected to a metal groove 16 on the lower transparent reaction chamber 5′. One end of the lower external metal electrode 7′ passes through and extends to the outside of the lower transparent reaction chamber 5′. A counter electrode 13 is provided inside the lower transparent reaction chamber 5′. The counter electrode 13 is fixed to the lower end of the lower transparent reaction chamber 5′ by the lower conductive elastic fixing ring 8′. An upper water inlet pipe 14 and a lower water outlet pipe 14′ are provided on the side wall of the lower transparent reaction chamber 5′. The upper water inlet pipe 14 and the lower water outlet pipe 14′ are located at the upper end and the lower end of the lower transparent reaction chamber 5′, respectively. The upper water inlet pipe 14 and the lower water outlet pipe 14′ are connected by a peristaltic pump pipeline to form a circulation path.
[0028] The membrane assembly includes an annular baffle 10, a cation exchange membrane 11, and a connecting layer 12. The connecting layer 12 is embedded and connected to the upper transparent reaction chamber 5 and the lower transparent reaction chamber 5'. The upper side of the connecting layer 12 is provided with an upper connecting layer groove 121 that connects to the upper transparent reaction chamber 5. The upper connecting layer groove 121 and the transparent reaction chamber 5 cooperate to fix the cation exchange membrane 11. The annular baffle 10 is provided between the fixed cation exchange membrane 11 and the catalyst 9. The lower side of the connecting layer 12 is also provided with a lower connecting layer groove 122 that is sealed and connected to the lower transparent reaction chamber 5'. The upper surface of the sealing cover plate 4 is provided with a handle 2. The lower transparent reaction chamber 5' and the upper transparent reaction chamber 5 have the same structure. Both the lower transparent reaction chamber 5' and the upper transparent reaction chamber 5 include a cylindrical connecting shell. An annular groove is provided on the inner side of each cylindrical connecting shell. A plastic groove 15 is provided inside the annular groove, and a metal groove 16 is provided inside the plastic groove 15. Both the plastic groove 15 and the metal groove 16 have arc-shaped cross-sections. The inner sides of the two metal grooves 16 are respectively fixedly connected to the upper conductive elastic fixing ring 8 and the lower conductive elastic fixing ring 8'. The upper conductive elastic fixing ring 8 and the lower conductive elastic fixing ring 8' have the same structure, and the upper conductive... Both the elastic retaining ring 8 and the lower conductive elastic retaining ring 8′ are non-completely closed annular structures to facilitate installation, replacement, and disassembly. Both the upper conductive elastic retaining ring 8 and the lower conductive elastic retaining ring 8′ have a three-spoke support structure built above them. The conductive elastic retaining ring has a notch, and the three-spoke support structure above it is integrated. Both the upper and lower conductive elastic retaining rings 8 and 8′ are made of elastic metal material. The conductive elastic retaining ring on the upper conductive elastic retaining ring 8 is tightly fitted to the catalyst 9, and the conductive elastic retaining ring on the upper conductive elastic retaining ring 8 provides circumferential support to the catalyst 9. The catalyst 9 is elastically pressed and fixed, and the conductive elastic fixing ring presses the catalyst 9 while allowing the catalyst 9 to be removed or replaced when needed. The metal groove 16 and the upper conductive elastic fixing ring 8 or the lower conductive elastic fixing ring 8′ form an electrode substrate. The catalyst 9 forms a working electrode with the metal groove 16 through a conductive connection. The conductive connection can be a press-fit, conductive adhesive bonding or conductive clamp connection to ensure low contact resistance and repeatable assembly. The ultrasonic liquid level detector 1 is electrically connected to the external control system. The ultrasonic liquid level detector 1 is used to detect the liquid level change in the upper transparent reaction chamber 5 in real time and to feed back and control the nitrate wastewater inlet flow rate and the peristaltic pump speed.An upper limit threshold for the liquid level is set in the external control system, which links the start / stop and speed of the liquid inlet solenoid valve and the peristaltic pump. The air inlet pipe 3′ on the upper transparent reaction chamber 5 is used to introduce inert gas or carrier gas, thereby carrying the ammonia gas escaping from the liquid phase to the ammonia outlet pipe for discharge and collection. The carrier gas can be nitrogen, argon or air. The liquid between the lower transparent reaction chamber 5′ and the upper transparent reaction chamber 5 is passed through the cation exchange membrane 11 and allows cation migration. The cation exchange membrane 11 provides an ion conduction channel between the two chambers and reduces cross-contamination; in conjunction with the local high pH of the cathode, it enables NH4; ⁺ The equilibrium shifts towards NH3, causing ammonia to escape in gaseous form. By creating a localized alkaline environment near the catalyst 9 electrode, rather than raising the overall system pH, alkali consumption is significantly reduced, improving the selectivity and efficiency of nitrate reduction to ammonia. The integrated design of electrocatalytic reduction and ammonia self-separation allows for in-situ removal of ammonia during generation, simplifying the process and reducing energy consumption and equipment investment. The "three-layer groove + notched conductive elastic fixing ring" structure ensures reliable fixation of catalyst 9 and facilitates rapid installation, replacement, and maintenance. The integrated metal groove current collection significantly reduces contact resistance and ensures uniform current distribution. The diaphragm and clamping structure provide reliable sealing, reducing bypass flow and cross-contamination, and improving ammonia separation efficiency. The transparent reaction chamber facilitates observation and light introduction, and is compatible with photoelectric coupling to enhance the reaction. Combined with the transparent reaction chamber, ultrasonic liquid level detection, and adjustable circulation path, it facilitates process monitoring and automatic control, reduces concentration polarization, and features a compact and highly modular structure, making it suitable for engineering scale-up and application promotion.
[0029] In use: When using, lay the cation exchange membrane 11 flat in the positioning surface of the connecting layer 12, so that the edge of the membrane covers the clamping area of the upper connecting layer groove 121; then install the circular baffle 10 to evenly press the edge of the membrane, and align and embed the connecting layer 12 with the lower transparent reaction chamber 5' and the upper transparent reaction chamber 5 according to the embedded structure. After locking, perform static water injection to check for leaks and confirm that the seal is reliable. Open the sealing cover 4, place the catalyst 9 in the corresponding area of the metal groove 16, so that it forms a conductive contact with the metal groove 16. After radially compressing the upper conductive elastic fixing ring 8 with a notch, insert it into the metal groove 16 and release it to make it spring back to achieve reliable locking and circumferential pressing and fastening. Confirm that the conductive elastic fixing ring 8 fixes the catalyst 9 firmly.
[0030] The counter electrode 13 is installed in the lower transparent reaction chamber 5′ and is pressed and fixed by the conductive elastic fixing ring 8′ of the counter electrode 13. The counter electrode 13 is connected to the external power supply through the lower external metal electrode 7′. The upper external metal electrode 7′ is connected to the negative terminal of the external DC power supply as the cathode terminal, and the lower external metal electrode 7′ is connected to the positive terminal of the external DC power supply as the anode terminal.
[0031] Nitrogen gas is connected to the inlet pipe 3′ and the inlet flow rate is set to 200 mL / min. Ammonia outlet pipe 3 is connected to the external absorption and collection unit. The ultrasonic liquid level detector 1 is set to a liquid level height of 150 mm in the upper transparent reaction chamber 5, and a closed-loop control logic is set to trigger liquid replenishment at a low liquid level of 145 mm and stop liquid replenishment at a high liquid level of 165 mm, so as to stabilize the inlet and outlet flow rates at 100 mL / min. Nitrate wastewater inlet pipe 6′ is connected to a metering pump or inlet valve control terminal, and nitrate wastewater outlet pipe 6 is connected to the outlet water collection terminal. The lower tank inlet pipe 14 and outlet pipe 14′ form a circulation loop through a peristaltic pump and the circulation flow rate is set to 800 mL / min.
[0032] After the liquid level and circulation in the upper transparent reaction chamber 5 are stable, turn on the external light source or place it in a sunlight-exposed area, with the light intensity preferably between 50 and 300 mW / cm², so that the light in the upper transparent reaction chamber 5 can be incident on the catalyst 9 area. At the same time, operate in constant current mode, with the current density set to 8 mA / cm², corresponding to a total current of approximately 10.0 A. During operation, nitrates undergo a reduction reaction on the surface of the cathode catalyst 9 and promote the escape of ammonia in the form of NH3 under a local alkaline environment. The escaped ammonia is discharged through the ammonia outlet pipe 3 under the action of nitrogen scavenging, achieving in-situ self-separation. When shutting down, first turn off the power and light source, maintain carrier gas scavenging for 5 minutes, and then stop the liquid inlet and circulation pump. When the catalyst needs to be replaced, the conductive elastic fixing ring 8 with a notch on the upper compression band can be quickly removed from the groove of the conductive elastic fixing ring, realizing convenient replacement of the catalyst 9 assembly.
[0033] 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.
Claims
1. A self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain, comprising a cathode assembly, a diaphragm assembly, and an anode assembly arranged vertically from top to bottom, characterized in that: The cathode assembly includes an upper transparent reaction chamber (5), and a sealing cover (4) is provided at the upper end of the upper transparent reaction chamber (5) to seal its upper end. An ammonia outlet pipe (3) and an ultrasonic liquid level detector (1) are provided on the sealing cover (4). An air inlet pipe (3′), a nitrate wastewater inlet pipe (6′) and a nitrate wastewater outlet pipe (6) are provided on the side wall of the upper transparent reaction chamber (5). An upper conductive elastic fixing ring (8) is provided inside the upper transparent reaction chamber (5). The catalyst (9) is fixed on the upper side of the membrane assembly by the upper conductive elastic fixing ring (8). The metal groove (16) on the upper transparent reaction chamber (5) is connected to an upper external metal electrode (7). One end of the upper external metal electrode (7) penetrates and extends to the outside of the upper transparent reaction chamber (5). The anode assembly includes a lower transparent reaction chamber (5′), inside which is a lower conductive elastic fixing ring (8′). A lower external metal electrode (7′) is connected to a metal groove (16) on the lower transparent reaction chamber (5′). One end of the lower external metal electrode (7′) extends through and to the outside of the lower transparent reaction chamber (5′). A counter electrode (13) is provided inside the lower transparent reaction chamber (5′). The elastic fixing ring (8′) fixes the counter electrode (13) to the lower end of the lower transparent reaction chamber (5′). The lower transparent reaction chamber (5′) is provided with an upper water inlet pipe (14) and a lower water outlet pipe (14′). The upper water inlet pipe (14) and the lower water outlet pipe (14′) are located at the upper end and the lower end of the lower transparent reaction chamber (5′), respectively. The upper water inlet pipe (14) and the lower water outlet pipe (14′) are connected by a peristaltic pump pipeline to form a circulation path. The membrane assembly includes an annular baffle (10), a cation exchange membrane (11), and a connecting layer (12). The connecting layer (12) is embedded and connected to the upper transparent reaction chamber (5) and the lower transparent reaction chamber (5′). The upper side of the connecting layer (12) is provided with an upper connecting layer groove (121) that is connected to the upper transparent reaction chamber (5). The upper connecting layer groove (121) and the upper transparent reaction chamber (5) cooperate to fix the cation exchange membrane (11). An annular baffle (10) is provided between the fixed cation exchange membrane (11) and the catalyst (9). The lower side of the connecting layer (12) is also provided with a lower connecting layer groove (122) that is sealed and connected to the lower transparent reaction chamber (5′).
2. The self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain as described in claim 1, characterized in that: The upper surface of the sealing cover (4) is provided with a handle (2).
3. The self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain according to claim 1, characterized in that: The lower transparent reaction chamber (5′) and the upper transparent reaction chamber (5) have the same structure. Both the lower transparent reaction chamber (5′) and the upper transparent reaction chamber (5) include a cylindrical connecting shell. The inner side of the cylindrical connecting shell is provided with an annular groove. The inside of the annular groove is provided with a plastic groove (15). The inside of the plastic groove (15) is provided with a metal groove (16). The cross-section of the plastic groove (15) and the metal groove (16) are both arc-shaped structures. The inner sides of the two metal grooves (16) are respectively fixedly connected to the upper conductive elastic fixing ring (8) and the lower conductive elastic fixing ring (8′).
4. The self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain according to claim 1, characterized in that: The upper conductive elastic fixing ring (8) and the lower conductive elastic fixing ring (8′) have the same structure. Both the upper conductive elastic fixing ring (8) and the lower conductive elastic fixing ring (8′) are non-completely closed ring structures to facilitate installation, replacement and disassembly. Both the upper conductive elastic fixing ring (8) and the lower conductive elastic fixing ring (8′) have a three-spoke support structure built on top of the conductive elastic fixing ring. The conductive elastic fixing ring has a notch. The three-spoke support structure built on top of the conductive elastic fixing ring is an integral unit. The upper conductive elastic fixing ring (8) and the lower conductive elastic fixing ring (8′) are made of elastic metal material.
5. The self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain according to claim 1, characterized in that: The conductive elastic fixing ring on the upper conductive elastic fixing ring (8) is tightly attached to the catalyst (9). The conductive elastic fixing ring on the upper conductive elastic fixing ring (8) elastically presses and fixes the catalyst (9) in the circumferential direction. While the conductive elastic fixing ring presses the catalyst (9), it allows the catalyst (9) to be removed or replaced when needed.
6. The self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain according to claim 3, characterized in that: The metal groove (16) forms an electrode substrate with the upper conductive elastic fixing ring (8) or the lower conductive elastic fixing ring (8′), and the catalyst (9) forms a working electrode with the metal groove (16) through conductive connection.
7. The self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain according to claim 1, characterized in that: The ultrasonic liquid level detector (1) is electrically connected to the external control system. The ultrasonic liquid level detector (1) is used to detect the liquid level change in the upper transparent reaction chamber (5) in real time and to feed back and control the nitrate wastewater inlet flow rate and the peristaltic pump speed.
8. The self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain according to claim 1, characterized in that: The inlet pipe (3′) on the upper transparent reaction chamber (5) is used to introduce inert gas or carrier gas, so as to carry the ammonia gas escaping from the liquid phase to the ammonia outlet pipe for discharge and collection.
9. The self-separating nitrate ammonia production device based on photoelectric coupling and cathode limiting domain according to claim 1, characterized in that: The cation exchange membrane (11) is used for the liquid between the lower transparent reaction chamber (5′) and the upper transparent reaction chamber (5) and allows cation migration. The cation exchange membrane (11) provides an ion conduction channel between the two chambers and reduces cross-contamination; in conjunction with the local high pH of the cathode, it enables NH4+ to pass through the liquid between the two chambers. ⁺ The equilibrium shifts towards NH3, causing ammonia to escape in gaseous form.