FCDI system and method for treating tail water and regeneration method of magnetic flow electrode

Abstract

The invention relates to the technical field of recirculating aquaculture equipment, in particular to an FCDI system and method for treating tail water and a regeneration method of a magnetic flowing electrode. The FCDI system includes a flowing capacitive deionization device, a regeneration device, and a control system. The flowing capacitance deionizing device is used for removing nitrogen ions and phosphorus ions in the tail water. Wherein the anode electrode chamber is used for introducing tail water to be treated, and the cathode electrode chamber is used for introducing a liquid magnetic flow electrode. And the regeneration device is used for recycling and regenerating the solid material in the magnetic flowing electrode after tail water treatment, and conveying the recycled and regenerated magnetic flowing electrode into the flowing capacitance deionization device again. The system can effectively treat nitrogen and phosphorus in tail water, does not depend on the environment temperature during treatment, can adapt to different environment conditions, and effectively solves the problem that biological nitration reaction depends on the environment temperature in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of circulating aquaculture equipment, and in particular to an FCDI system and method for treating tail water, and a regeneration method for a magnetic flow electrode. Background Art

[0002] Facility-based recirculating aquaculture is an efficient aquaculture method, but it also produces a large amount of nitrogen and phosphorus pollutants, which will threaten the water environment. In the process of facility-based recirculating aquaculture, effective management of water quality is a key factor in ensuring the health of aquaculture organisms and increasing production. Therefore, during the aquaculture process, it is necessary to effectively remove the pollutants such as nitrogen and phosphorus produced to maintain the balance of the water environment. At present, the commonly used method for removing nitrogen and phosphorus from water bodies is to use biological nitrification reactions for denitrification, which generally requires an ambient temperature of 20℃-30℃. However, this treatment process is highly dependent on the ambient temperature, and the suitable temperature for this treatment method is generally 20℃-30℃. In winter, when the water temperature is low, if biological nitrification reactions are used to remove nitrogen and phosphorus from water bodies, their removal efficiency will be greatly reduced. In addition, the existing biological nitrification reactions need to maintain specific pH and dissolved oxygen levels, which makes the entire biological nitrification reaction operation more complicated, and the biological nitrification reaction time is longer, which will also affect its treatment efficiency. Summary of the invention

[0003] In order to solve the problem in the prior art that the treatment of nitrogen and phosphorus in water by biological nitrification reaction is dependent on the ambient temperature and the treatment efficiency is greatly reduced in a low temperature environment, the present invention provides a FCDI system and method for treating tail water, and a regeneration method for a magnetic flow electrode.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: an FCDI system for treating tail water, which includes a mobile capacitive deionization device, which is used to remove nitrogen ions and phosphorus ions in the tail water; the mobile capacitive deionization device includes a cathode electrode chamber, an anode electrode chamber and an ion exchange membrane, the anode electrode chamber is used to pass the tail water to be treated, the cathode electrode chamber is used to pass the liquid magnetic flow electrode, the ion exchange membrane is arranged between the cathode electrode chamber and the anode electrode chamber and separates the cathode electrode chamber and the anode electrode chamber, and the ion exchange membrane is used to allow ion exchange between the cathode electrode chamber and the anode electrode chamber while preventing the tail water to be treated from directly contacting the magnetic flow electrode;

[0005] A power source 2, the power source 2 is used to apply voltage or current to the flow capacitor deionization device; a regeneration device, which is used to recycle and regenerate the solid materials in the magnetic flow electrode after treating the tail water, when the conductivity of the magnetic flow electrode in the cathode electrode chamber is lower than the set threshold value 1, the magnetic flow electrode moves from the cathode electrode chamber to the regeneration device, and the regeneration device is able to recycle and regenerate the magnetic flow electrode, and the magnetic flow electrode after the recycling and regeneration process can enter the flow capacitor deionization device again;

[0006] and a control system for controlling the operation or shutdown of the entire FCDI system.

[0007] As a further improvement of the present invention, the FCDI system also includes a magnetic flow electrode trough, which is used to store the magnetic flow electrodes, and the magnetic flow electrode trough is connected to the flow capacitor deionization device and is used to transport the magnetic flow electrodes to the flow capacitor deionization device; when the FCDI system is running, a part of the magnetic flow electrodes in the magnetic flow electrode trough is located in the cathode electrode chamber, and another part of the magnetic flow electrodes is located in the regeneration device; the magnetic flow electrodes located in the cathode electrode chamber are used to adsorb nitrogen ions and phosphorus ions in the anode electrode chamber, and the magnetic flow electrodes located in the regeneration device can enter the magnetic flow electrode trough again after being recycled and regenerated by the regeneration device, and be transported to the flow capacitor deionization device again through the magnetic flow electrode trough; wherein, when the conductivity of the magnetic flow electrode after being treated by the regeneration device is higher than the set threshold value two, the magnetic flow electrode located in the regeneration device can be transported to the magnetic flow electrode trough.

[0008] As a further improvement of the present invention, the magnetic flow electrode comprises a solid material and an electrode liquid, wherein the solid material is mixed in the electrode liquid to form a liquid magnetic flow electrode, wherein the solid material comprises a conductive material, polypyrrole and magnetic carbon particles, wherein the mass ratio of the conductive material, the polypyrrole and the magnetic carbon particles is 2:1:5; the mass fraction of the solid material in the magnetic flow electrode is 1.5% to 5%; the preparation of the magnetic carbon particles comprises the following steps: taking 20 g of Fe(NO) with a concentration of 0.259 mol / L and a volume of 100 mL; 3 ) 3 Mixing to obtain a mixture 1;

[0009] Add HNO to mixture 1 3 To adjust the pH value of mixture 1 so that the pH value of mixture 1 is 2;

[0010] The pH-adjusted mixture was stirred at 100°C to form Fe(OH) 3 precipitation; then the surface with Fe(OH) 3 The precipitated activated carbon was calcined at 600°C in a nitrogen atmosphere to make Fe(OH) 3 Part of Fe 3+ Reduced to Fe 2+ , thus generating Fe on the surface of activated carbon 3 O 4 ;

[0011] The calcined surface has Fe 3 O 4 After the activated carbon is cooled, washed and dried, the magnetic carbon particles are obtained.

[0012] As a further improvement of the present invention, the conductive material is one of graphene, copper nanoparticles or carbon black.

[0013] As a further improvement of the present invention, the preparation of the solid material includes: (1) pre-treating the prepared magnetic carbon particles, the pre-treatment step is: dispersing the prepared magnetic carbon particles in ethanol or deionized water, using ultrasonic treatment for 30 minutes to ensure that the particles are evenly dispersed; (2) adding pyrrole monomer and an appropriate amount of oxidant (such as ammonium persulfate, APS, etc.) to the magnetic carbon particle dispersion, stirring the reaction for 2-4 hours, and controlling the reaction temperature at 0°C-5°C to form a uniform polypyrrole coating on the surface of the magnetic carbon particles. After the polymerization is completed, the magnetic carbon particles are filtered, washed and dried; (3) the dried magnetic carbon particles coated with the polypyrrole coating are mixed with carbon black, and the mixed particles are homogenized by mechanical stirring or ball milling to obtain a solid material; (4) the mixed solid material is vacuum dried at 100°C to ensure that the obtained solid material has a stable structure.

[0014] As a further improvement of the present invention, the electrode liquid is a NaCl solution.

[0015] As a further improvement of the present invention, the regeneration device includes a shell, the shell is provided with a cavity, an aeration pipe, a power source and at least a pair of electromagnetic rods are installed in the cavity; the power source is used to energize the pair of electromagnetic rods, one of the pair of electromagnetic rods is positively charged and the other is negatively charged after energization, and the negatively charged electromagnetic rod is used to adsorb solid materials in the magnetic flow electrode entering the cavity; the aeration pipe is installed at the bottom of the cavity and is used to introduce gas into the cavity to aerate the solid materials in the cavity.

[0016] As a further improvement of the present invention, the gas introduced into the aeration pipe is air or oxygen.

[0017] As a further improvement of the present invention, the FCDI system also includes a water supply system, which includes a water pump and a pipeline. The water pump is installed on the pipeline, one end of the pipeline is connected to the tail water in the circulating aquaculture system, and the other end of the pipeline is connected to the water inlet of the anode electrode chamber. The water pump can transport the tail water to be treated into the anode electrode chamber through the pipeline.

[0018] As a further improvement of the present invention, the FCDI system further comprises a tail water collection system, the tail water collection system is connected to the liquid outlet of the anode electrode chamber, and the tail water collection system is used to uniformly collect the treated tail water.

[0019] The present invention also includes a method for regenerating a magnetic flow electrode, which recycles and regenerates the magnetic flow electrode through the regeneration device in the FCDI system for treating tail water. The method for regenerating the magnetic flow electrode includes the following steps:

[0020] The magnetic flow electrode after treating the tail water is transported to the cavity of the regeneration device, and the power supply is turned on to energize the pair of electromagnetic rods, so that one of the electromagnetic rods is positively charged and the other is negatively charged, and the solid materials in the magnetic flow electrode in the cavity are all adsorbed on the negatively charged electromagnetic rod;

[0021] When all the solid materials in the magnetic flow electrode in the cavity are adsorbed on the negatively charged electromagnetic rod, the water outlet of the regeneration device is opened to discharge all the electrode liquid in the magnetic flow electrode; then, NaOH solution is introduced into the regeneration device, and the power supply of the regeneration device is turned off, so that the solid materials adsorbed on the negatively charged electromagnetic rod can fall into the cavity of the regeneration device, and the solid materials in the regeneration device are aerated, stirred and cleaned;

[0022] After cleaning is completed, power supply 1 is started again to energize the pair of electromagnetic rods, so that all the cleaned solid materials can be adsorbed on the negatively charged electromagnetic rods. Then, the NaOH solution in the regeneration device is discharged and new electrode liquid is introduced. When the electrode liquid in the regeneration device is filled, power supply 1 is turned off. At this time, the regenerated solid materials can enter the new electrode liquid. The electrode liquid mixed with the solid materials is the regenerated magnetic flow electrode.

[0023] The present invention also includes a method for treating tail water, which uses the FCDI system for treating tail water to denitrify and dephosphorize the tail water. The method for treating tail water by the FCDI system includes the following steps:

[0024] S1, starting the water supply system to introduce the tail water to be treated into the anode electrode chamber of the mobile capacitive deionization device;

[0025] S2, turning on power supply 2, the magnetic flow electrode located in the cathode electrode chamber adsorbs nitrogen ions and phosphorus ions in the tail water to be treated located in the anode electrode chamber onto the solid material; the tail water with nitrogen ions and phosphorus ions removed is discharged through the drain port of the anode electrode chamber;

[0026] Among them, in the process of adsorbing nitrogen ions and phosphorus ions in the tail water to be treated by the magnetic flow electrode in step S2, if the control system shows that the conductivity of the magnetic flow electrode in the cathode electrode chamber is lower than the set threshold value one, the magnetic flow electrode in the cathode electrode chamber can be transported to the regeneration device for recovery and regeneration treatment, and the magnetic flow electrode slot can transport the regenerated magnetic flow electrode to the cathode electrode chamber, and the magnetic flow electrode in the cathode electrode chamber is replaced by the magnetic flow electrode slot and the regeneration device, so that the conductivity of the magnetic flow electrode in the cathode electrode chamber is always higher than the set threshold value one.

[0027] The technical solution provided by the present invention has the following beneficial effects:

[0028] (1) The present invention prepares magnetic activated carbon particles, which have a short reaction time for adsorbing nitrogen and phosphorus, can effectively remove nitrogen and phosphorus from water bodies, reduce eutrophication of water bodies, and are also magnetic, so that the adsorbed magnetic activated carbon particles can be quickly separated from the water body by magnetic separation, so as to achieve recycling. By flexibly combining the high adsorption capacity of magnetic carbon particles with the flowing electrode liquid, a new water treatment technology is created, which improves the efficiency of denitrification and dephosphorization, and can adapt to different environmental conditions, effectively solving the problem of biological nitrification reaction dependence on ambient temperature in the prior art, and providing a new tailwater treatment solution for the field of recirculating aquaculture.

[0029] (2) The FCDI system of the present invention can effectively treat tail water without polluting the environment, and the whole operation is simple and convenient, and the treatment cost is low, so that it can be widely used in the treatment of tail water in the facility-based circulating aquaculture system. In addition, by providing a regeneration device and a magnetic flow electrode tank, the treatment efficiency can be guaranteed while the tail water can be continuously treated, thereby greatly improving the treatment efficiency of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural flow chart of the FCDI system provided by the present invention.

[0031] Figure 2 This is a schematic structural diagram of the mobile capacitive deionization device provided by the present invention.

[0032] Figure 3 It is a schematic diagram of the structure of the regeneration device of the present invention.

[0033] In the figure: 1. mobile capacitive deionization device; 11. cathode electrode chamber; 12. anode electrode chamber; 13. ion exchange membrane; 2. regeneration device; 21. shell; 22. cavity; 221. aeration pipe; 222. electromagnetic rod; 3. water supply system; 4. tail water collection system. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0035] In the description of the present invention, it should be noted that for directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating directions and positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific protection scope of the present invention. The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The terms "including" and "having" in the specification and claims of the present invention and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device including a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] Please refer to Figure 1 An embodiment of the present invention provides an FCDI system for treating tail water, which includes a flow capacitor deionization device 1, a magnetic flow electrode tank, a power supply 2, a regeneration device 2, a control system, a water supply system 3 and a tail water collection system 4.

[0037] The magnetic flow electrode is in liquid state. It can be recycled in the FCDI system to effectively adsorb pollutants such as nitrogen ions and phosphorus ions in the tail water. The magnetic flow electrode is used to adsorb nitrogen ions and phosphorus ions in the tail water of the circulating aquaculture system. The magnetic flow electrode includes solid materials and electrode liquid, and the solid materials are mixed in the electrode liquid to form a liquid magnetic flow electrode; the solid materials include conductive materials, polypyrrole and magnetic carbon particles, and the mass ratio of the conductive materials, the polypyrrole and the magnetic carbon particles is 2:1:5; the mass fraction of the solid material in the magnetic flow electrode is 2.5% to 3.5%.

[0038] The conductive material can be one of graphene, copper nanoparticles or carbon black. By adding an appropriate amount of conductive material to the magnetic flow electrode, the conductivity of the prepared magnetic flow electrode can be improved to enhance the electrochemical reaction efficiency between the magnetic flow electrode and the pollutants in the tail water.

[0039] The electrode liquid may be a NaCl solution. In this embodiment, the electrode liquid is a NaCl solution, which can provide a necessary ion environment for the electrochemical reaction to maintain the flow of current.

[0040] In this embodiment, magnetic carbon particles can be prepared by the following method: 20 g of 100 mesh DARCO activated carbon and 100 mL of Fe(NO3) with a concentration of 0.259 mol / L 3 The solutions were mixed to obtain a mixture 1. HNO was added to the mixture 1. 3 The pH value of the mixture was adjusted to 2. The pH-adjusted mixture was stirred in a 100°C water bath for 8 h to form Fe(OH) 3 Then the surface with Fe(OH) 3 The precipitated activated carbon was calcined at 600 °C for 100 min under nitrogen atmosphere to make Fe(OH) 3 Part of Fe 3+ Reduced to Fe 2+ , thus generating Fe on the surface of activated carbon 3 O 4 Finally, the calcined surface has Fe 3 O 4 The activated carbon is cooled, washed and dried to obtain magnetic carbon particles.

[0041] The mass ratio of the magnetic carbon particles to the conductive material in the solid material may also be 5:1 to 4.5:1.

[0042] The particle size of the prepared magnetic carbon black particles is 20-30 μm. The particle size of the conductive material is 20-40 nm, and the conductivity is not less than 10 S / m.

[0043] Activated carbon is an adsorbent with a high surface area and porous structure, and has a good adsorption effect on organic and inorganic substances such as ammonia nitrogen (NH3-N) and total phosphorus (TP). In this embodiment, magnetic activated carbon particles are prepared, and the reaction time of adsorbing nitrogen and phosphorus is short, which can effectively remove nitrogen and phosphorus in water bodies and reduce eutrophication of water bodies. In addition, the magnetic activated carbon particles have magnetism, so that the adsorbed magnetic activated carbon particles can be quickly separated from the water body by magnetic separation, so as to realize recycling.

[0044] The preparation of the solid material includes the following steps: (1) pre-treating the prepared magnetic carbon particles, the pre-treatment step is: dispersing the prepared magnetic carbon particles in ethanol or deionized water, using ultrasonic treatment for 30 minutes to ensure that the particles are evenly dispersed; (2) adding pyrrole monomer and an appropriate amount of oxidant (such as ammonium persulfate, APS, etc.) to the magnetic carbon particle dispersion, stirring the reaction for 2-4 hours, and controlling the reaction temperature at 0°C-5°C to form a uniform polypyrrole coating on the surface of the magnetic carbon particles. After the polymerization is completed, the magnetic carbon particles are filtered, washed and dried; (3) the dried magnetic carbon particles coated with the polypyrrole coating are mixed with carbon black, and the mixed particles are homogenized by mechanical stirring or ball milling to obtain a solid material; (4) the mixed solid material is vacuum dried at 100°C to ensure that the obtained solid material has a stable structure.

[0045] Among them, by adding polypyrrole, polypyrrole can coat the magnetic carbon particles, making the bond between polypyrrole and the magnetic carbon particles stronger, and preventing the magnetic carbon particles from falling off or stratifying.

[0046] The magnetic flow electrode is assembled as follows: the prepared solid material is immersed in a NaCl solution with a concentration of 1 mol / L, thereby assembling the magnetic flow electrode. In this embodiment, by utilizing the high-efficiency adsorption of magnetic carbon particles and the flexible combination of flowing electrode liquid, a new water treatment technology is created, which improves the efficiency of nitrogen and phosphorus removal and can adapt to different environmental conditions, providing a new tail water treatment solution for the field of recirculating aquaculture.

[0047] The magnetic flow electrode has an adsorption removal rate of nitrogen and phosphorus of not less than 85% and 90% respectively, an electrode resistivity of ≤0.5Ω·m, stable flow performance, and no particle deposition. The adsorption experiment was carried out under the conditions of a solution concentration of 10mg / L, a flow rate of 5mL / min, and room temperature.

[0048] Please refer to Figure 2The mobile capacitive deionization device 1 includes a cathode electrode chamber 11, an anode electrode chamber 12 and an ion exchange membrane 13. The water supply system 3 is used to transport the tail water to be treated to the anode electrode chamber 12, and the cathode electrode chamber 11 is used to pass the liquid magnetic flow electrode. The ion exchange membrane 13 is arranged between the cathode electrode chamber 11 and the anode electrode chamber 12 and separates the cathode electrode chamber 11 and the anode electrode chamber 12. The ion exchange membrane 13 is used to allow ion exchange between the cathode electrode chamber 11 and the anode electrode chamber 12 while preventing the tail water to be treated from directly contacting the magnetic flow electrode. By providing the ion exchange membrane 13, not only can the material loss of the magnetic flow electrode be prevented, but also the ion exchange efficiency can be improved, thereby improving the deionization efficiency of the magnetic flow electrode.

[0049] The ion exchange membrane 13 may be an anion exchange membrane 13 or a cation exchange membrane 13 .

[0050] The anion exchange membrane 13 is usually made of materials such as polystyrene sulfonate or polysulfonated polyether enyl ether ketone.

[0051] The cation exchange membrane 13 is usually made of a polyolefin-based material coupled with a quaternary ammonium salt group.

[0052] The water supply system 3 is connected to the flowing capacitor deionization device 1, and the water supply system 3 is used to transport the tail water to be treated to the flowing capacitor deionization device 1. The power supply 2 is used to supply power to the flowing capacitor deionization device 1. The regeneration device 2 is connected to the flowing capacitor deionization device 1, and the regeneration device 2 is used to recycle and regenerate the magnetic flow electrode in the flowing capacitor deionization device 1, so that the solid material in the magnetic flow electrode treated by the regeneration device 2 can be recycled again, thereby reducing the cost of the entire tail water treatment process.

[0053] The water supply system 3 includes a water pump and a pipeline. The water pump is installed on the pipeline. One end of the pipeline is connected to the tail water in the circulating aquaculture system, and the other end of the pipeline is connected to the water inlet of the anode electrode chamber 12. The water pump can transport the tail water to be treated to the anode electrode chamber 12 through the pipeline, thereby realizing the denitrification and dephosphorization treatment of the tail water in the circulating aquaculture equipment. The tail water after denitrification and dephosphorization can enter the tail water collection system 4 through the liquid outlet in the anode electrode chamber 12. The tail water collection system 4 is used to uniformly collect the treated tail water.

[0054] Power supply two is used for applying stable voltage or current to mobile capacitor deionization device 1, to drive ions to migrate between magnetic flow electrode and tail water, so as to realize the purpose of removing nitrogen ions and phosphorus ions by magnetic flow electrode.Power supply two has certain adjustment range, can realize regulating the size of voltage or current, to adapt to the different operating conditions of FCDI system.In actual operation process, can adjust the size of voltage or current according to the actual operating condition of FCDI system, to optimize the deionization efficiency and energy consumption of mobile capacitor deionization device 1.Power supply two has certain adjustment range simultaneously, can also ensure that power supply two can output in safe range under different operating conditions, to prevent the situation of overvoltage or overcurrent from occurring.

[0055] The control system may be a microprocessor or a programmable logic controller, which is used to control the output of the second power source and adjust the output parameters according to real-time data (such as ion concentration, current density, etc.).

[0056] The FCDI system also includes sensors and feedback systems. The sensors can be current, temperature, voltage, pH, conductivity and other sensors, which are used to sense the current, temperature, voltage, pH, conductivity and other parameters in the FCDI system and transmit the data to the control system to achieve real-time monitoring of the FCDI system. The feedback system is used to ensure that the FCDI system responds to changes in actual operating conditions.

[0057] The control system is also provided with a user interface and a display screen. The user interface can be a touch screen or a button, which is used to set or adjust various parameters of the FCDI system during operation, and the display screen is used to display the real-time system status and operation data of the FCDI system. The control system is a common control system in the prior art, so it is not described in detail in the solution of the present invention.

[0058] The magnetic flow electrode tank is used to store the magnetic flow electrode. The magnetic flow electrode tank is connected to the flow capacitor deionization device 1, and is used to transport the magnetic flow electrode to the flow capacitor deionization device 1. Specifically, when the FCDI system is just running, the magnetic flow electrode tank is used to transport the magnetic flow electrode in its tank to the cathode electrode chamber 11, and at the same time transport the tail water to be treated in the water supply system 3 to the anode electrode chamber 12, and power is supplied to the flow capacitor deionization device 1 through the power supply. Under the action of the current, the nitrogen ions, phosphorus ions, etc. in the anode electrode chamber 12 can enter the cathode electrode chamber 11 through the ion exchange membrane 13, and the solid material of the magnetic flow electrode in the cathode electrode chamber 11 can adsorb the nitrogen ions and phosphorus ions.

[0059] Please refer to Figure 3The regeneration device 2 includes a shell 21, and the shell 21 is provided with a cavity 22. An aeration tube 221, a power source 1, and at least one pair of electromagnetic rods 222 are installed in the cavity 22. The power source 1 is used to energize the pair of electromagnetic rods 222. After energization, one of the pair of electromagnetic rods 222 is positively charged and the other is negatively charged. The negatively charged electromagnetic rod 222 is used to adsorb the solid materials in the magnetic flow electrode entering the cavity 22. The aeration tube 221 is installed at the bottom of the cavity 22 and is used to pass gas into the cavity 22 to perform aeration treatment on the solid materials in the cavity 22. By providing the electromagnetic rod 222, the solid materials in the magnetic flow electrode can be adsorbed during the treatment of the magnetic flow electrode, so that the solid materials in the magnetic flow electrode can be recycled and reused in the regeneration device 2, thereby reducing the processing cost of the entire system.

[0060] The gas introduced into the aeration pipe 221 is air or oxygen.

[0061] In this embodiment, the operation of the FCDI system can be divided into the following stages:

[0062] Before operation: first transport the tail water to be treated to the anode electrode chamber 12, and transport the magnetic flow electrode to the cathode electrode chamber 11. At the same time, the operator can set the required voltage, conductivity and other parameters through the interface. After setting, the control system is initialized and prepares for power output. At this time, the system starts to run. During the operation, the control system can adjust the output of the power supply according to the set parameter values ​​and sensor feedback. And during the processing process, if the control system detects that the parameters deviate from the preset range, the system will automatically adjust. If the system is abnormally diligent, the system will also automatically adjust or stop output to ensure the stability and safety of the entire system operation.

[0063] During operation: After the FCDI system has been running for a period of time, when the conductivity of the magnetic flow electrode in the cathode electrode chamber 11 is lower than the threshold value set by the control system, the control system can control the liquid outlet end of the cathode electrode chamber 11 to open, so that the magnetic flow electrode in the cathode electrode chamber 11 enters the regeneration device 2, and the regeneration device 2 can recycle and regenerate the entered magnetic flow electrode. At the same time, the magnetic flow electrode slot can transport the un-ionized magnetic flow electrode into the cathode electrode chamber 11, so as to replace the magnetic flow electrode in the cathode electrode chamber 11, thereby ensuring that the magnetic flow electrode in the cathode electrode chamber 11 always has good conductivity, thereby improving the processing effect and efficiency of the entire system.

[0064] At the same time, the magnetic flow electrode entering the regeneration device 2 can be recycled and regenerated in the regeneration device 2. The regeneration method of the magnetic flow electrode of the regeneration device 2 includes the following steps: the magnetic flow electrode after the tail water is treated is transported to the cavity 22 of the regeneration device 2, and the power supply is turned on to energize a pair of electromagnetic rods 222, so that one of the electromagnetic rods 222 is positively charged and the other electromagnetic rod 222 is negatively charged, and the solid materials in the magnetic flow electrode in the cavity 22 are all adsorbed on the negatively charged electromagnetic rod 222. When the solid materials in the magnetic flow electrode in the cavity 22 are all adsorbed on the negatively charged electromagnetic rod 222, the water outlet of the regeneration device 2 is opened to discharge all the electrode liquid in the magnetic flow electrode. Subsequently, NaOH solution is introduced into the regeneration device 2, and the power supply of the regeneration device 2 is turned off, so that the solid materials adsorbed on the negatively charged electromagnetic rod 222 fall into the cavity 22 of the regeneration device 2, and the solid materials in the regeneration device 2 are aerated, stirred and cleaned. After the cleaning is completed, the power supply 1 is turned on to energize the pair of electromagnetic rods 222, and the cleaned solid materials are all adsorbed on the negatively charged electromagnetic rods 222. Then, the NaOH solution in the regeneration device 2 is discharged and a new electrode liquid is introduced, and the power supply 1 is turned off when the electrode liquid in the regeneration device 2 is filled. At this time, the regenerated solid materials are able to enter the new electrode liquid, and the electrode liquid mixed with the solid materials is the regenerated magnetic flow electrode.

[0065] This embodiment realizes the recovery and reuse of solid materials in the magnetic flow electrode by setting up a regeneration device 2. It can utilize the high-efficiency adsorption of magnetic carbon particles to effectively adsorb nitrogen and phosphorus ions in the tail water. It can also realize adsorption and recovery and regeneration through the electromagnetic rod 222, thereby realizing the recycling of solid materials and greatly reducing the processing cost.

[0066] The FCDI system in this embodiment can effectively treat tail water without polluting the environment. The entire operation is simple and convenient, and the treatment cost is low, so it can be widely used in tail water treatment in facility-based recirculating aquaculture systems.

[0067] The tail water is continuously treated by the FCDI system running stably until all the tail water to be treated is treated, and then the operation of the FCDI system is stopped.

[0068] During the operation of the entire system, the magnetic flow electrode and the ion exchange membrane 13 can be checked regularly. If any problem occurs, they can be replaced immediately to ensure stable operation of the system.

[0069] It can be understood that the FCDI system in this embodiment may also include a cleaning fluid circulation system, which is used to regularly clean the entire FCDI system, thereby ensuring that the entire system can operate stably.

[0070] It is understandable that during the treatment process, the magnetic flow electrode can monitor the conductivity in the regeneration device 2 through the conductivity sensor to determine whether the red magnetic flow electrode in the regeneration device 2 has been treated. If the control system shows that the conductivity in the regeneration device 2 exceeds the set threshold value 2, it means that the solid material in the magnetic flow electrode has been treated. Then, the electrode liquid can be transported to the regeneration device 2, and the electrode liquid can be mixed with the solid material to form a recovered and regenerated magnetic flow electrode.

[0071] In this embodiment, the threshold 1 and the threshold 2 can be set according to the values ​​required in the actual processing process.

[0072] It is understandable that in the process of recycling and regenerating the magnetic flow electrode, the FCDI system may also be provided with an electrode liquid storage device, which is used to generate electrode liquid and transport the new electrode liquid to the regeneration device 2, and to form a regenerated magnetic flow electrode by mixing with the solid material recovered and processed in the regeneration device 2. Alternatively, the magnetic flow electrode tank may also be provided with an electrode liquid treatment device, and the electrode flowing out of the regeneration device 2 may also be transported to the electrode liquid treatment device through a pipeline, and the electrode liquid treatment device can recycle the incoming electrode liquid so that it can be reused. It is understandable that the specific structure of the electrode liquid treatment device for treating the electrode liquid can be any device in the prior art that can achieve the above operation.

[0073] It is understood that the method for treating tail water by the FCDI system in this embodiment includes the following steps:

[0074] S1, start the water supply system 3, and introduce the tail water to be treated into the anode electrode chamber 12 of the mobile capacitive deionization device 1.

[0075] S2, turn on the power supply 2, the magnetic flow electrode located in the cathode electrode chamber 11 adsorbs the nitrogen ions and phosphorus ions in the tail water to be treated in the anode electrode chamber 12 onto the solid material. The tail water with nitrogen ions and phosphorus ions removed is discharged to the tail water collection system 4 through the drain port of the anode electrode chamber 12.

[0076] Among them, in the process of adsorbing nitrogen ions and phosphorus ions in the tail water to be treated by the magnetic flow electrode in step S2, if the control system shows that the conductivity of the magnetic flow electrode in the cathode electrode chamber 11 is lower than the set threshold value one, the magnetic flow electrode in the cathode electrode chamber 11 can be transported to the regeneration device 2 for recycling and regeneration treatment. At the same time, the magnetic flow electrode slot can transport the magnetic flow electrode to the cathode electrode chamber 11, and the magnetic flow electrode in the cathode electrode chamber 11 is replaced by the magnetic flow electrode slot and the regeneration device 2, so that the conductivity of the magnetic flow electrode in the cathode electrode chamber 11 is always higher than the set threshold value one. This ensures that the cathode electrode chamber 11 can continuously and efficiently denitrify and dephosphorize the tail water, thereby greatly improving the treatment efficiency of the entire system for tail water.

[0077] In other embodiments, there may be two regeneration devices, and the two regeneration devices may work alternately to form a cycle. In this embodiment, the two regeneration devices may be named regeneration device A and regeneration device B. The specific operation is as follows: the mobile electrode that needs to be regenerated in the mobile capacitor deionization device can flow into the regeneration device A, and the liquid in the mobile electrode is discharged, leaving only the solid material in the regeneration device A. The solid material can be regenerated through the regeneration device A, and then the new electrode liquid can flow into the regeneration device A first, and mix with the regenerated solid material to form a new mobile electrode, and the new mobile electrode can flow into the regeneration device B, and the above operation can be a positive cycle. After the mobile capacitor deionization device has worked for a period of time, the mobile electrode that needs to be regenerated can flow into the regeneration device B, and the liquid in the mobile electrode is discharged, leaving only the solid material in the regeneration device B. The solid material can be regenerated through the regeneration device B, and then the new electrode liquid can flow into the regeneration device B first, and mix with the regenerated solid material to form a new mobile electrode, and the new mobile electrode can flow into the regeneration device A, and the above operation can be a reverse cycle. The positive and reverse cycles are one cycle. Through the alternating operation of the positive and reverse cycles, the continuity of the flow electrode can be guaranteed.

[0078] The tail water treatment method in this embodiment has the advantages of strong temperature adaptability, high decontamination efficiency and environmental friendliness, and is not only suitable for facility-based recirculating aquaculture, but can also be extended to fields such as urban sewage treatment. Compared with the prior art, the present invention provides a new and efficient water treatment solution, which is particularly suitable for water treatment occasions at low temperatures or water bodies that are sensitive to changes in ambient temperature.

[0079] In order to verify the FCDI tailwater treatment system of the present invention and its technical advantages in low temperature environment, tailwater from four different regions in Anhui Province was selected for low temperature (≤10℃) treatment experiments from November to December 2024. The experimental water samples included samples with high initial concentrations of total nitrogen (in terms of N) and total phosphorus (in terms of P). The following data were obtained:

[0080] Location water sample Total nitrogen (N), mg / L Total phosphorus (P), mg / L Region 1 2.21 0.23 Region 2 1.40 0.13 Region Three 0.99 0.11 Region 4 1.14 0.11

[0081] Experiments show that under low temperature conditions, the method of the present invention has excellent removal efficiency for total nitrogen and total phosphorus in tail water, and the treatment effect is better than that of traditional biological methods.

[0082] The above describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and the specification only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A FCDI system for treating tail water, characterized in that: It includes: A mobile capacitive deionization device (1) is used to remove nitrogen ions and phosphorus ions in tail water; the mobile capacitive deionization device (1) comprises a cathode electrode chamber (11), an anode electrode chamber (12) and an ion exchange membrane (13); the anode electrode chamber (12) is used to introduce tail water to be treated; the cathode electrode chamber (11) is used to introduce a liquid magnetic flow electrode; the ion exchange membrane (13) is arranged between the cathode electrode chamber (11) and the anode electrode chamber (12) and separates the cathode electrode chamber (11) and the anode electrode chamber (12); the ion exchange membrane (13) is used to allow ion exchange between the cathode electrode chamber (11) and the anode electrode chamber (12) while preventing the tail water to be treated from directly contacting the magnetic flow electrode; A power source 2, the power source 2 is used to apply voltage or current to the mobile capacitor deionization device (1); a regeneration device (2), which is used to recycle and regenerate solid materials in the magnetic flow electrode after treating tail water, when the conductivity of the magnetic flow electrode in the cathode electrode chamber (11) is lower than a set threshold value 1, the magnetic flow electrode moves from the cathode electrode chamber (11) to the regeneration device (2), and the regeneration device (2) is able to recycle and regenerate the magnetic flow electrode, and the magnetic flow electrode after recycling and regeneration can enter the mobile capacitor deionization device (1) again; and a control system for controlling the operation or shutdown of the entire FCDI system.

2. The FCDI system for treating tail water according to claim 1, characterized in that: The FCDI system further comprises a magnetic flow electrode trough for storing the magnetic flow electrodes, the magnetic flow electrode trough being connected to the mobile capacitor deionization device (1) and being used to transport the magnetic flow electrodes to the mobile capacitor deionization device (1); when the FCDI system is in operation, a portion of the magnetic flow electrodes in the magnetic flow electrode trough are located in the cathode electrode chamber (11), and another portion of the magnetic flow electrodes are located in the regeneration device (2); the magnetic flow electrodes located in the cathode electrode chamber (11) are used to adsorb nitrogen ions and phosphorus ions in the anode electrode chamber (12), and the magnetic flow electrodes located in the regeneration device (2) can enter the magnetic flow electrode trough again after being recycled and regenerated by the regeneration device (2), and can be transported to the mobile capacitor deionization device (1) again through the magnetic flow electrode trough; wherein, when the conductivity of the magnetic flow electrodes after being treated by the regeneration device (2) is higher than a set threshold value 2, the magnetic flow electrodes located in the regeneration device (2) can be transported to the magnetic flow electrode trough.

3. The FCDI system for treating tail water according to claim 2, characterized in that, The magnetic flow electrode comprises a solid material and an electrode liquid, wherein the solid material is mixed in the electrode liquid to form a liquid magnetic flow electrode, wherein the solid material comprises a conductive material, polypyrrole and magnetic carbon particles, wherein the mass ratio of the conductive material, the polypyrrole and the magnetic carbon particles is 2:1:5; the mass fraction of the solid material in the magnetic flow electrode is 2.5% to 3.5%; and the preparation of the magnetic carbon particles comprises the following steps: Take 20g of activated carbon with a concentration of 0.259mol / L and mix it with Fe(NO3)3 with a volume of 100mL to obtain mixture 1; Adding HNO3 to the mixture 1 to adjust the pH value of the mixture 1 so that the pH value of the mixture 1 is 2; The pH-adjusted mixture was stirred at 100°C to form Fe(OH)3 precipitation on the surface of the activated carbon; the activated carbon with Fe(OH)3 precipitation on the surface was then calcined at 600°C in a nitrogen atmosphere to reduce the Fe(OH)3 content of the activated carbon to 100°C. 3+ Reduced to Fe 2+ , thereby generating Fe3O4 on the surface of activated carbon; The magnetic carbon particles are obtained by cooling, washing and drying the calcined activated carbon with Fe3O4 on the surface.

4. The FCDI system for treating tail water according to claim 3, characterized in that: The conductive material is one of graphene, copper nanoparticles and carbon black; And / or, the electrode liquid is a NaCl solution.

5. The FCDI system for treating tail water according to claim 1, characterized in that: The regeneration device (2) comprises a shell (21), the shell (21) is provided with a cavity (22), an aeration pipe (221), a power source 1 and at least a pair of electromagnetic rods (222) are installed in the cavity (22); the power source 1 is used to energize the pair of electromagnetic rods (222), one of the pair of electromagnetic rods (222) is positively charged and the other is negatively charged after energization, and the negatively charged electromagnetic rod (222) is used to absorb solid materials in the magnetic flow electrode entering the cavity (22); the aeration pipe (221) is installed at the bottom of the cavity (22) and is used to introduce gas into the cavity (22) to aerate the solid materials in the cavity (22).

6. The FCDI system for treating tail water according to claim 5, characterized in that: The gas introduced into the aeration pipe (221) is air or oxygen.

7. The FCDI system for treating tail water according to claim 3, characterized in that: The FCDI system further comprises a water supply system (3), wherein the water supply system (3) comprises a water pump and a pipeline, wherein the water pump is installed on the pipeline, wherein one end of the pipeline is connected to the tail water in the circulating aquaculture system, and the other end of the pipeline is connected to the water inlet of the anode electrode chamber (12), so that the water pump can transport the tail water to be treated to the anode electrode chamber (12) through the pipeline.

8. The FCDI system for treating tail water according to claim 3, characterized in that: The FCDI system further comprises a tail water collection system (4), wherein the tail water collection system (4) is connected to the liquid outlet of the anode electrode chamber (12), and the tail water collection system (4) is used to uniformly collect the treated tail water.

9. A method for regenerating a magnetic flow electrode, characterized in that: The regeneration device (2) in the FCDI system for treating tail water according to any one of claims 1 to 8 is used to recycle and regenerate the magnetic flow electrode, and the regeneration method of the magnetic flow electrode comprises the following steps: The magnetic flow electrode after treating the tail water is transported to the cavity (22) of the regeneration device (2), and the power supply is turned on to energize a pair of electromagnetic rods (222), so that one of the electromagnetic rods (222) is positively charged and the other electromagnetic rod (222) is negatively charged, and the solid materials in the magnetic flow electrode in the cavity (22) are all adsorbed on the negatively charged electromagnetic rod (222); When all the solid materials in the magnetic flow electrode in the cavity (22) are adsorbed on the negatively charged electromagnetic rod (222), the water outlet of the regeneration device (2) is opened to discharge all the electrode liquid in the magnetic flow electrode; then, NaOH solution is introduced into the regeneration device (2), and the power supply of the regeneration device (2) is turned off, so that the solid materials adsorbed on the negatively charged electromagnetic rod (222) fall into the cavity (22) of the regeneration device (2), and the solid materials in the regeneration device (2) are aerated, stirred and cleaned; After cleaning is completed, power source 1 is started again to energize the pair of electromagnetic rods (222), so that all the cleaned solid materials are adsorbed on the negatively charged electromagnetic rods (222). Then, the NaOH solution in the regeneration device (2) is discharged and new electrode liquid is introduced. When the electrode liquid in the regeneration device (2) is filled, power source 1 is turned off. At this time, the regenerated solid materials are able to enter the new electrode liquid. The electrode liquid mixed with the solid materials is the regenerated magnetic flow electrode.

10. A method for treating tail water, characterized in that: The tail water is denitrified and dephosphorized by the FCDI system for treating tail water according to any one of claims 1 to 8, and the method for treating tail water by the FCDI system comprises the following steps: S1, starting the water supply system (3) and introducing tail water to be treated into the anode electrode chamber (12) of the mobile capacitive deionization device (1); S2, turning on power supply 2, the magnetic flow electrode located in the cathode electrode chamber (11) adsorbs nitrogen ions and phosphorus ions in the tail water to be treated located in the anode electrode chamber (12) onto the solid material; the tail water from which nitrogen ions and phosphorus ions have been removed is discharged through the drain port of the anode electrode chamber (12); Among them, in the process of adsorbing nitrogen ions and phosphorus ions in the tail water to be treated by the magnetic flow electrode in step S2, if the control system shows that the conductivity of the magnetic flow electrode in the cathode electrode chamber (11) is lower than the set threshold value one, the magnetic flow electrode in the cathode electrode chamber (11) is transported to the regeneration device (2) for recovery and regeneration treatment, and the magnetic flow electrode slot is used to transport the regenerated magnetic flow electrode to the cathode electrode chamber (11). The magnetic flow electrode in the cathode electrode chamber (11) is replaced by the magnetic flow electrode slot and the regeneration device (2), so that the conductivity of the magnetic flow electrode in the cathode electrode chamber (11) is always higher than the set threshold value one.

Images