Recovery device for adsorbing ammonia nitrogen and phosphorus in water by flowing electrode capacitance

Abstract

The invention relates to the technical field of recovery equipment, in particular to a device for recovering ammonia nitrogen and phosphorus in flowing electrode capacitive adsorption water, which comprises a shell, an anode barrel and a cathode barrel are arranged in the shell, and the shell is provided with a water inlet and a water outlet; an anode strip, a self-corrosion electrode plate for generating ferrous ions and a breather pipe are arranged in the anode barrel, and the self-corrosion electrode plate is made of an iron material; a cathode piece, zeolite and a recovery assembly for recovering zeolite and ammonia gas are arranged in the cathode barrel, an anode generates iron phosphate precipitate which can be directly used as an agricultural phosphate fertilizer, a cathode recovers high-purity ammonia gas and is used for nitrogen fertilizer production, two different ions can be removed at the same time by introducing two different flowing electrodes, the removal efficiency is greatly improved, and the production cost is reduced. The self-corrosion electrode plate continuously releases Fe < 2 + > which is combined with PO4 < 3-> for precipitation, anode passivation is avoided, and cathode zeolite is regenerated through heating, so that chemical cleaning is avoided.

Description

Technical Field

[0001] This invention relates to the field of recycling equipment technology, and in particular to a device for recovering ammonia nitrogen and phosphorus from water by capacitive adsorption of flowing electrodes. Background Technology

[0002] In today's world, where resources are increasingly scarce, wastewater treatment and resource recycling have received widespread attention. Ammonia nitrogen (NH4) + ) and soluble phosphates (PO4) 3- Ammonia nitrogen, a common nitrogen and phosphorus pollutant, is widely found in various water bodies, including domestic sewage, industrial wastewater, agricultural runoff, and landfill leachate. Its accumulation can lead to eutrophication, causing excessive algal growth and further disrupting the balance of aquatic ecosystems. Meanwhile, nitrogen and phosphorus are key elements for plant growth, especially in agriculture, where they hold significant economic value. Therefore, effectively recovering ammonia nitrogen from wastewater and converting it into usable nitrogen fertilizer—achieving both wastewater purification and promoting nitrogen recycling—makes research into ammonia nitrogen recovery technology particularly important.

[0003] Currently, traditional wastewater treatment technologies, such as biological treatment, primarily remove ammonia nitrogen from water bodies by converting it into harmless nitrogen gas (N2), while phosphorus is absorbed by microorganisms to form activated sludge, which is then disposed of through landfill. While this method effectively purifies water, it also results in the loss of nitrogen and phosphorus resources. Furthermore, traditional methods are energy-intensive, complex, and cannot achieve the recovery and utilization of ammonia nitrogen. In contrast, electrochemical separation technology, with its advantages of high selectivity, low energy consumption, and high efficiency, shows great potential for the recovery and utilization of nutrients in wastewater. For example, flow-electrode capacitive deionization (FCDI) technology can remove ammonia nitrogen. However, current research mainly focuses on packing materials and principles, lacking practically usable devices, or the devices are relatively simple and can only handle single ions. Additionally, the packing materials used have certain deficiencies in terms of recovery or sourcing, requiring pre-preparation or complex treatment for recycling, making it difficult to simultaneously achieve efficient adsorption, separation, and resource recovery of ammonia nitrogen and phosphorus. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the fact that the research in the prior art focuses on the packing and principle research, without practical devices, or the devices are relatively simple and can only handle single ions. In addition, the packing used has certain defects in terms of recovery or source, and needs to be prepared in advance or undergo complicated treatment before it can be recycled. The present invention provides a device for recovering ammonia nitrogen and phosphorus in water by capacitive adsorption of flowing electrodes.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a recovery device for ammonia nitrogen and phosphorus in water by capacitive adsorption of flowing electrode, including a shell, an anode tank and a cathode tank arranged inside the shell, and an inlet and an outlet on the shell. The anode barrel contains an anode plate, a self-corroding electrode plate for generating ferrous ions, and a vent pipe. The self-corroding electrode plate is made of iron. The upper end of the vent pipe is used to supply a mixture of air and carbon dioxide gas, and the lower end of the vent pipe is used to supply a mixture of air and carbon dioxide gas. An anode sieve is opened on the side of the anode barrel relative to the cathode barrel. A mud discharge pipe is installed on the bottom surface of the anode barrel. The outlet of the mud discharge pipe passes through the outer shell and extends to the outside of the outer shell. The cathode tank contains cathode plates, zeolite, and a recovery assembly for recovering zeolite and ammonia. The cathode plates are located between the cathode tank and the recovery assembly. A cathode sieve is provided on the side of the cathode tank opposite the anode tank. Ferric phosphate precipitate (FePO4) is generated at the anode, which can be directly used as agricultural phosphate fertilizer. High-purity ammonia (NH3) is recovered at the cathode for nitrogen fertilizer production. Introducing two different flow electrodes allows for the simultaneous removal of two different ions, significantly improving removal efficiency. The self-corroding electrode plate continuously releases Fe... 2+ , with PO4 3- By combining precipitation to avoid anodic passivation, the cathode zeolite is regenerated by heating, avoiding chemical cleaning.

[0006] To address the issues of easy short circuits and low processing efficiency caused by water inlet, the system further includes a water inlet located at the bottom of the casing and an outlet located at the top of the casing, with the water inlet and outlet arranged diagonally.

[0007] To address the issue of high ion migration resistance between the anode and cathode, the minimum distance between the anode and cathode barrels is further reduced to 0.5-1 cm.

[0008] To address the issue of sediment buildup and blockage, the anode tank is further designed with a sloping bottom surface that gradually slopes downwards from the center of the outer shell, and the inlet of the sludge discharge pipe is aligned with the lower end of the sloping bottom surface.

[0009] To address the issue of water flow disturbance affecting sedimentation, the anode tank is further equipped with several baffles spaced at intervals in the lower part to stabilize the water flow, with a spacing of 3-8 cm between adjacent baffles.

[0010] To address the issues of uneven dispersion and weak ion mobility, the anode barrel is further equipped with a stirring assembly for agitating the fluid. The stirring assembly includes a motor, a stirring ring, and blades. The motor is fixedly connected to the outer wall of the casing, the stirring ring is located inside the anode barrel, and the output shaft of the motor is drivenly connected to the stirring ring. The motor provides power for the rotation of the stirring ring, and the blades are arranged on the stirring ring.

[0011] To address the issue of low zeolite utilization efficiency, a recycling component is further included, comprising a recycling tank, a heater, and a recycling hood. The recovery tank is used to recover zeolite and guide it to the location of the cathode plate. The recovery tank is arranged inside the cathode tank. There are two return ports on the side of the recovery tank near the cathode plate, and the two return ports are distributed vertically. There is a guide pipe on the inner wall of the recovery tank. The guide pipe is located between the two return ports. The guide pipe has a guide cavity that narrows from bottom to top and inward. The top surface of the guide pipe is a guide surface that slopes towards the upper return port. The lowest point of the guide surface is close to the upper return port. The heater is located inside the recycling bin and below the flow guide pipe; The recovery hood and cathode tank are fixedly connected, and the recovery hood is used to recover ammonia.

[0012] To address the issue of high energy consumption due to heat loss, the material of the recycling bin is further improved to include heat-insulating material.

[0013] To address the issue of cross-contamination between anode and cathode ions, the method further includes installing an anode ion membrane on the anode tank that covers the anode sieve holes, and installing a cathode ion membrane on the cathode tank that covers the cathode sieve holes.

[0014] To address the issue of insufficient oxidation of the self-corroding electrode plate, the design further includes ensuring that the lower end of the vent pipe is flush with or lower than the lower end of the self-corroding electrode plate, with the self-corroding electrode plate located at the upper end of the anode barrel.

[0015] The beneficial effects of this invention are as follows: This invention provides a mobile electrode capacitive adsorption recovery device for ammonia nitrogen and phosphorus in water. The anode generates ferric phosphate precipitate (FePO4), which can be directly used as agricultural phosphate fertilizer. The cathode recovers high-purity ammonia gas (NH3) for nitrogen fertilizer production. Introducing two different mobile electrodes allows for the simultaneous removal of two different ions, greatly improving removal efficiency. The self-corroding electrode plate continuously releases Fe... 2+ , with PO4 3- By combining precipitation to avoid anodic passivation, the cathode zeolite is regenerated by heating, avoiding chemical cleaning; The flow electrode material used in this device is easy to prepare and recycle, and the operation can be automatically controlled, making it a promising candidate for application in water treatment and nutrient recovery. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a top view of the structure of the present invention; Figure 2 This is a cross-sectional structural diagram of the present invention.

[0018] In the diagram: 1. Outer shell; 11. Inlet; 12. Outlet. 2. Anode barrel; 21. Anode plate; 22. Self-corroding electrode plate; 23. Vent pipe; 24. Sludge discharge pipe; 25. Anode sieve hole; 26. Anode ion membrane; 27. Sloping bottom surface; 28. Baffle plate. 3. Cathode barrel; 31. Cathode plate; 32. Zeolite; 33. Recovery assembly; 331. Recovery barrel; 3311. Return port; 332. Heater; 333. Recovery cover; 334. Guide pipe; 3341. Guide cavity; 3342. Guide surface; 335. Guide plate; 34. Cathode sieve hole; 35. Cathode ion membrane. 4. Stirring components; 41. Motor; 42. Stirring ring; 43. Blades. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0020] like Figure 1 This is a schematic diagram of the structure of the present invention. A device for recovering ammonia nitrogen and phosphorus in water by capacitive adsorption of flowing electrodes includes a shell 1, an anode tank 2 and a cathode tank 3 arranged inside the shell 1, and an inlet 11 and an outlet 12 opened on the shell 1. The inlet 11 is located at the lower part of the shell 1, and the outlet 12 is located at the upper part of the shell 1. The inlet 11 and the outlet 12 are arranged diagonally, which prolongs the flow channel and improves the contact time and removal rate of pollutants.

[0021] The minimum distance between the anode barrel 2 and the cathode barrel 3 is 0.5-1cm. The 0.5-1cm narrow slit design enhances the electric field strength and accelerates ion migration.

[0022] like Figure 1 , 2 As shown, the anode tank 2 contains an anode plate 21, a self-etching electrode plate 22 for generating ferrous ions, and a vent pipe 23. The self-etching electrode plate 22 is made of iron. The upper end of the vent pipe 23 is used for inputting a mixture of air and carbon dioxide, and the lower end is used for outputting the mixture of air and carbon dioxide. An anode sieve hole 25 is provided on the side of the anode tank 2 opposite to the cathode tank 3. A mud discharge pipe 24 is installed on the bottom surface of the anode tank 2. The outlet of the mud discharge pipe 24 passes through the outer shell 1 and extends to the outside of the outer shell 1. The lower end of the vent pipe 23 is flush with or lower than the lower end of the self-etching electrode plate 22. The self-etching electrode plate 22 is located at the upper end of the anode tank 2. An anode ion membrane 26 that can cover the anode sieve hole 25 is installed on the anode tank 2. The anode ion membrane 26 and the cathode ion membrane 35 selectively allow the target ions (PO4) to pass through. 3- / NH4 + To improve adsorption efficiency, the low-level gas supply through vent pipe 23 ensures Fe... 2+Full contact with the gas mixture improves oxidation efficiency; The bottom surface of the anode tank 2 is a sloping bottom surface 27 that gradually slopes downward from the center of the outer shell 1. The inlet of the sludge discharge pipe 24 is aligned with the lower end of the sloping bottom surface 27. The sloping bottom surface 27 guides the sludge to accumulate in the sludge discharge pipe 24 to avoid sedimentation.

[0023] The lower part of the anode tank 2 is equipped with several baffles 28 arranged at intervals to stabilize the water flow. The distance between two adjacent baffles 28 is 3-8cm. The baffles 28 (3-8cm spacing) stabilize the water flow and promote the accumulation and sedimentation of impurities.

[0024] like Figure 1 , 2 As shown, an agitator assembly 4 for stirring the fluid is installed on the inner wall of the anode tank 2. The agitator assembly 4 includes a motor 41, an agitator ring 42, and blades 43. The motor 41 is fixedly connected to the outer wall of the housing 1. The agitator ring 42 is located inside the anode tank 2. The output shaft of the motor 41 is connected to the agitator ring 42 for transmission. The motor 41 is used to provide power for the rotation of the agitator ring 42. The blades 43 are arranged on the agitator ring 42. The agitator assembly 4 enhances mixing and improves phosphorus precipitation efficiency.

[0025] like Figure 1 , 2 As shown, the cathode barrel 3 is equipped with a cathode plate 31, zeolite 32, and a recovery assembly 33 for recovering zeolite 32 and ammonia. The cathode plate 31 is located between the cathode barrel 3 and the recovery assembly 33. The cathode barrel 3 has a cathode sieve hole 34 on the side opposite to the anode barrel 2. A cathode ion membrane 35 that can cover the cathode sieve hole 34 is installed on the cathode barrel 3.

[0026] Zeolite 32 with a particle size of 1-4 mm was soaked in a 1-3 mol / L solution of disodium ethylenediaminetetraacetate for 16-24 hours, followed by solid-liquid separation and drying.

[0027] The recycling assembly 33 includes a recycling bin 331, a heater 332, and a recycling hood 333; The recovery tank 331 is used to recover zeolite 32 and guide it to the location of the cathode plate 31. The recovery tank 331 is arranged inside the cathode tank 3. Two return ports 3311 are opened on the side of the recovery tank 331 near the cathode plate 31, and the two return ports 3311 are distributed vertically at intervals. The inner wall of the recovery tank 331 has a guide pipe 334, which is located between the two return ports 3311. The guide pipe 334 has a guide cavity 3341 that narrows from bottom to top and inward. When heated, the density of water decreases and it also moves upward. Gas on the surface of zeolite 32 is also released to form bubbles, which also move upward. The guide cavity 3341 is narrower at the top and wider at the bottom (i.e., it narrows from bottom to top and inward). The purpose is to accelerate the movement speed of zeolite 32 and water in the upper and middle parts, so that zeolite 32 can be completely carried out and dead zones can be avoided. The top surface of the guide pipe 334 is a guide surface 3342 that is inclined towards the upper return port 3311. The low point of the guide surface 3342 is close to the upper return port 3311. The guide pipe 334 uses the air lift effect to realize the automatic circulation of zeolite 32. A guide plate 335 is installed between the recovery tank 331 and the cathode tank 3 to guide zeolite 32 to the lower return port 3311. The guide plate 335 is arranged below the lower return port 3311 of the two return ports 3311. The guide plate 335 has a conical structure that tapers from top to bottom and inward. Furthermore, two circumferentially spaced baffles can be installed between the recovery tank 331 and the cathode tank 3, with the baffles extending radially along the cathode tank 3. The reflux port 3311 is located between the two baffles. The cathode tank 3, the recovery tank 331, the baffles, and the guide plate 335 enclose a reflux area. The reflux area is used to restrict the flow of zeolite 32 so that it can enter the reflux port 3311 located below and flow into the recovery tank 331.

[0028] The heater 332 is arranged inside the recycling bin 331 and is located below the flow guide pipe 334; The recovery cover 333 and the cathode tank 3 are fixedly connected. The recovery cover 333 is used to recover ammonia. The recovery tank 331 is made of heat insulation material. The heat insulation material recovery tank 331 reduces heat loss and lowers operating costs.

[0029] Treatment process: Inlet and pretreatment. Wastewater enters the outer casing 1 from the diagonally arranged inlet 11, flows through the gap between the anode tank 2 and the cathode tank 3 (spacing 0.5~1cm), and under the drive of the electric field, NH4+... + Migration towards the cathode, PO4 3- Migrate towards the anode.

[0030] Connect the DC power supply between the anode plate 21 and the cathode plate 31, maintaining the voltage between 30-60V. Connect the DC power supply between the self-corroding electrode plates 22. PO4 3-It penetrates the anodic ion exchange membrane 26 and enters the anode tank 2; after energizing, it self-corrodes the electrode plate 22 (iron plate) and dissolves to produce Fe. 2+ The vent pipe 23 blows in a CO2 mixture (volume ratio 1:1-2), which in turn blows in Fe. 2+ Oxidized to Fe 3+ Fe(OH)3 colloid is generated; stirring component 4 promotes the reaction of ferric hydroxide colloid with PO4. 3- The precipitate of iron phosphate is formed by combining and then slides through the inclined bottom surface 27 into the sludge discharge pipe 24 for discharge and collection as phosphate fertilizer.

[0031] NH4 + The saturated zeolite 32 penetrates the cathode ion exchange membrane 35 and is adsorbed by zeolite 32; the saturated zeolite 32 sinks into the recovery tank 331 through the reflux port 3311, and is heated by the heater 332, where NH4+... + It decomposes into NH3 gas; the ammonia gas carries the zeolite 32 upward, and the gas is collected by the recovery hood 333 to be used as nitrogen fertilizer; after the zeolite 32 is decelerated in the guide pipe 334, it slides back to the cathode area along the guide surface 3342 for recycling.

[0032] After the treated water is demined of phosphate and ammonium ions, it is discharged from outlet 12. The precipitated iron phosphate can be used as fertilizer in field planting, and the collected ammonia can also be used as nitrogen fertilizer.

[0033] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A device for recovering ammonia nitrogen and phosphorus from water by capacitive adsorption using a flowing electrode, characterized in that, The system includes an outer casing, inside which an anode tank and a cathode tank are arranged, and an inlet and an outlet are provided on the outer casing. The anode barrel contains an anode plate, a self-corroding electrode plate for generating ferrous ions, and a vent pipe. The self-corroding electrode plate is made of iron. The upper end of the vent pipe is used to input a mixture of air and carbon dioxide, and the lower end of the vent pipe is used to output the mixture of air and carbon dioxide. An anode sieve is provided on the side of the anode barrel opposite to the cathode barrel. A mud discharge pipe is installed on the bottom surface of the anode barrel. The outlet of the mud discharge pipe passes through the outer shell and extends to the outside of the outer shell. The cathode barrel contains a cathode plate, zeolite, and a recovery assembly for recovering zeolite and ammonia. The cathode plate is located between the cathode barrel and the recovery assembly. The cathode barrel has cathode sieve holes on the side opposite to the anode barrel.

2. The device for recovering ammonia nitrogen and phosphorus in water by capacitive adsorption of a flowing electrode as described in claim 1, characterized in that: The water inlet is located at the lower part of the outer casing, and the water outlet is located at the upper part of the outer casing, with the water inlet and water outlet arranged diagonally.

3. The device for recovering ammonia nitrogen and phosphorus from water by capacitive adsorption of a flowing electrode as described in claim 1, characterized in that: The minimum distance between the anode barrel and the cathode barrel is 0.5-1cm.

4. The device for recovering ammonia nitrogen and phosphorus in water by capacitive adsorption of a flowing electrode as described in claim 1, characterized in that: The bottom surface of the anode barrel is a sloping bottom surface that gradually slopes downward from the outside away from the center of the outer shell, and the inlet of the mud discharge pipe is aligned with the lower end of the sloping bottom surface.

5. The device for recovering ammonia nitrogen and phosphorus from water by capacitive adsorption of a flowing electrode as described in claim 1, characterized in that: The lower part of the anode tank is equipped with several baffles at intervals to stabilize the water flow, with a spacing of 3-8 cm between two adjacent baffles.

6. The device for recovering ammonia nitrogen and phosphorus in water by capacitive adsorption of a flowing electrode as described in claim 1, characterized in that: The inner wall of the anode tank is equipped with a stirring assembly for agitating the fluid. The stirring assembly includes a motor, a stirring ring, and blades. The motor is fixedly connected to the outer wall of the housing. The stirring ring is located inside the anode tank. The output shaft of the motor is drivenly connected to the stirring ring. The motor is used to provide power for the rotation of the stirring ring. The blades are arranged on the stirring ring.

7. The device for recovering ammonia nitrogen and phosphorus from water by capacitive adsorption of a flowing electrode as described in claim 1, characterized in that: The recycling assembly includes a recycling bin, a heater, and a recycling hood; The recycling bin is used to recycle zeolite and guide it to the location of the cathode plate. The recycling bin is arranged inside the cathode bin. The recycling bin has two return ports on the side near the cathode plate, and the two return ports are distributed vertically. The inner wall of the recycling bin has a guide pipe, which is located between the two return ports. The guide pipe has a guide cavity that narrows from bottom to top and inwards. The top surface of the guide pipe is a guide surface that slopes towards the upper return port, and the lowest point of the guide surface is close to the upper return port. The heater is arranged inside the recycling bin and is located below the flow guide pipe; The recovery hood and the cathode tank are fixedly connected, and the recovery hood is used to recover ammonia gas. A guide plate is installed between the recovery tank and the cathode tank to guide the zeolite into the lower reflux port, the guide plate being positioned below the lower reflux port of the two reflux ports.

8. The device for recovering ammonia nitrogen and phosphorus from water by capacitive adsorption of a flowing electrode as described in claim 7, characterized in that: The recycling bin is made of thermal insulation material.

9. The device for recovering ammonia nitrogen and phosphorus in water by capacitive adsorption of a flowing electrode as described in claim 1, characterized in that: An anodic ion membrane capable of covering the anode sieve holes is installed on the anode barrel, and a cathode ion membrane capable of covering the cathode sieve holes is installed on the cathode barrel.

10. The device for recovering ammonia nitrogen and phosphorus in water by capacitive adsorption of a flowing electrode as described in claim 1, characterized in that: The lower end of the vent pipe is flush with or lower than the lower end of the self-corroding electrode plate, which is located at the upper end of the anode barrel.

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