Device and method for treating phosphorus-containing wastewater and recovering phosphorus resources using an iron-air battery

Abstract

The present invention discloses a device and method for treating phosphorus-containing wastewater and recovering phosphorus resources by an iron-air battery. The positive and negative electrodes respectively use a low-cost iron electrode and an air electrode. Wastewater containing phosphate is added to the anode chamber, and a sodium chloride solution is added to the cathode chamber as an electrolyte; the negative and positive chambers are separated by a proton exchange membrane and connected by an external wire. The potential difference causes the iron anode to lose electrons, and the generated ferrous ions react with the phosphate in the anode liquid to generate blue iron ore; the electrons reach the air electrode via an external wire, and the oxygen in the air reacts with the electrons received by the cathode to generate water; the protons inside the battery move through the proton exchange membrane to form a loop, and an open circuit voltage of 1.2V can be generated in the external circuit. The present invention uses the ferrous ions generated in situ by the iron electrode as a dephosphorizing agent, and without introducing other impurity ions, it realizes wastewater dephosphorization, and can also recover phosphorus resources and electric energy in the wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a device and method for treating phosphorus-containing wastewater and recovering phosphorus resources by using an iron-air battery. Background Art

[0002] Phosphorus is one of the main causes of eutrophication of water bodies, and phosphorus removal from wastewater is an effective way to prevent and control eutrophication of water bodies. Wastewater phosphorus removal technologies are mainly divided into two categories: chemical and biological methods. Biological methods are widely used because of their economic and environmental advantages, but they also face problems such as long reaction time, large equipment footprint, and difficulty in sludge treatment; chemical phosphorus removal methods are promoted and applied because of their economic and efficient, simple operation, reliable effect, and not easily affected by wastewater quality. Ferrous salts are often used as flocculants for chemical phosphorus removal from wastewater, with the advantages of high efficiency and safety. Reasonable control of ferrous salt phosphorus removal conditions can produce a high-value mineral containing phosphorus and iron - blue iron ore. Blue iron ore with high crystallinity can be used to make crystals and other decorations, and powdered blue iron ore can be used as farmland fertilizer or painting dye.

[0003] Phosphorus resources are extremely unevenly distributed on the earth and their reserves are very limited. With the growth of population and the continuous improvement of human living standards, society's demand for phosphorus is getting higher and higher. Therefore, how to transform "phosphorus removal" in wastewater into "phosphorus reuse" has become the development trend of wastewater phosphorus removal, and new green and environmentally friendly phosphorus resource recovery technologies need to be explored urgently. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention proposes a device and method for treating phosphorus-containing wastewater and recovering phosphorus resources using an iron-air battery. The present invention can simultaneously recover phosphorus resources and electrical energy, turning waste into treasure.

[0005] In order to achieve the above object, the specific scheme adopted by the present invention is as follows:

[0006] An iron-air battery device for treating phosphorus-containing wastewater and recovering phosphorus resources comprises a cathode chamber and an anode chamber, a proton exchange membrane is provided between one side of the cathode chamber and one side of the anode chamber and is sealed and connected, an air electrode is provided on the other side of the cathode chamber, a cathode chamber electrolyte circulation system is connected to the cathode chamber, and a wire is connected to the air electrode, the wire extending to the outside of the cathode chamber;

[0007] The anode chamber is provided with an anode chamber water inlet, an iron electrode and a dephosphorization product outlet. The dephosphorization product outlet is located at the bottom of the anode chamber. The iron electrode is arranged in the anode chamber. A wire is connected to the iron electrode and extends to the outside of the anode chamber.

[0008] The cathode chamber electrolyte circulation system comprises an electrolyte inlet, a water inlet pipe, an electrolyte storage tank, a connecting pipe, a circulation pump, a water outlet pipe and an electrolyte outlet. The electrolyte inlet is arranged at the lower part of one side of the cathode chamber, and the electrolyte outlet is arranged at the upper part of the other side of the cathode chamber; the electrolyte inlet is connected to the electrolyte storage tank through the water inlet pipe, the water inlet of the circulation pump is connected to the electrolyte storage tank through the connecting pipe, and the water outlet of the circulation pump is connected to the electrolyte outlet through the water outlet pipe.

[0009] In the cathode chamber electrolyte circulation system, the distance from the electrolyte inlet to the bottom is 1 / 3 of the total height of the cathode chamber, the distance from the electrolyte outlet to the bottom is 2 / 3 of the total height of the cathode chamber, and the ratio of the inner diameter of the electrolyte inlet to the electrolyte outlet is 1:1.

[0010] An external blade slot is embedded in the upper part of the anode chamber, and the iron electrode passes through the external blade slot and is suspended in the middle of the anode chamber. A wire is connected to the upper end of the iron electrode. Two blades are arranged in a V shape in the external blade slot, and the iron electrode passes through the space between the two blades.

[0011] A dephosphorization product collecting bucket is arranged at the bottom of the anode chamber, and the outlet of the dephosphorization product collecting bucket serves as a dephosphorization product discharge outlet.

[0012] The volume ratio of the cathode chamber to the anode chamber is 1:1.

[0013] The anode chamber is added with phosphorus-containing wastewater, the concentration of which is 5-1000 mg-p / L, and the cathode chamber uses a 1-3 mol / L sodium chloride solution as an electrolyte.

[0014] Every 3.5-4cm 3 The anode chamber is configured with 1-1.5cm 2 Iron electrode; every 1.1-1.5cm 3 The cathode chamber is configured with 1-1.2cm 2 of the air electrode.

[0015] Every 1.1-1.5cm 3 The cathode chamber is configured with 1-1.2cm 2 of proton exchange membrane.

[0016] A method for treating phosphorus-containing wastewater and recovering phosphorus resources using an iron-air battery comprises the following steps:

[0017] The phosphate-containing wastewater is introduced into the anode chamber from the anode chamber water inlet as the anode liquid;

[0018] Adding catholyte into the cathode chamber;

[0019] Connect the wire connected to the iron electrode to the wire connected to the air electrode or to an electrical load;

[0020] The iron electrode in the anode chamber loses electrons to generate soluble divalent iron, and the soluble divalent iron ions enter the anode liquid and react with the phosphate ions in the anode liquid to generate blue iron ore precipitation; the blue iron ore is discharged through the dephosphorization product discharge port;

[0021] The electrons lost by the iron electrode are transferred to the air electrode;

[0022] The catholyte accepts electrons at the air electrode;

[0023] The proton exchange membrane separates the anode chamber and the cathode chamber, and maintains the charge balance between the anode chamber and the cathode chamber through proton exchange.

[0024] The beneficial effects of the present invention are:

[0025] The iron-air battery device for treating phosphorus-containing wastewater and recovering phosphorus resources of the present invention uses cheap and easily available zero-valent iron as an anode, thereby reducing the cost of removing phosphorus from wastewater; the phosphorus-containing wastewater is used as an anode liquid, the iron electrode loses electrons, and the generated ferrous ions react with phosphates in the anode liquid to generate blue iron ore, thereby realizing the recovery and utilization of phosphorus resources in the phosphorus-containing wastewater and turning waste into treasure; at the same time, a wire is connected to the iron electrode and a wire is connected to the air electrode. When in use, the two wires are connected to a power-consuming load or an electric energy recovery device, thereby achieving the purpose of power generation; the cathode chamber electrolyte circulation system makes the cathode liquid concentration in the cathode chamber relatively uniform, thereby ensuring reaction efficiency and stable power generation capacity.

[0026] Furthermore, after a period of reaction, the synthetic blue iron ore will cover the surface of the iron anode, causing it to passivate and reducing the ability of the iron anode to lose electrons. Therefore, a blade slot is provided to facilitate surface cleaning and ensure stable power generation performance.

[0027] The method for treating phosphorus-containing wastewater and recovering phosphorus resources by using an iron-air battery of the present invention can utilize zero-valent iron to treat phosphate-containing wastewater to obtain cyanite. Zero-valent iron is cheap and easy to obtain, so the cost is low. The obtained product cyanite realizes the reuse of phosphorus resources in wastewater, turning waste into treasure, and can also obtain electric energy in the process of treating wastewater. Therefore, the method of the present invention is environmentally friendly, can utilize waste, and has low cost. It is a new type of green and environmentally friendly phosphorus resource recovery technology, which is suitable for industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is an overall diagram of the device for treating phosphorus-containing wastewater and recovering phosphorus resources using an iron-air battery according to the present invention;

[0029] Figure 2 It is a cross-sectional view of the device for treating phosphorus-containing wastewater and recovering phosphorus resources by the iron-air battery of the present invention;

[0030] Figure 3This is an overall diagram of the cathode chamber of the device for treating phosphorus-containing wastewater and recovering phosphorus resources with an iron-air battery of the present invention;

[0031] Figure 4 It is a cross-sectional view of the cathode chamber of the device for treating phosphorus-containing wastewater and recovering phosphorus resources by the iron-air battery of the present invention;

[0032] Figure 5 It is a cross-sectional view of the anode chamber of the iron-air battery device for treating phosphorus-containing wastewater and recovering phosphorus resources of the present invention.

[0033] In the figure: cathode chamber A, anode chamber B; first cover 1, sealing gasket 2, air electrode 3, external wire port Ⅰ4, cathode chamber electrolyte circulation system 5, electrolyte inlet 5-1, water inlet pipe 5-2, electrolyte storage tank 5-3, connecting pipe 5-4, circulation pump 5-5, water outlet pipe 5-6, electrolyte outlet 5-7; proton exchange membrane 6; anode chamber water inlet 7, external wire port Ⅱ8, external blade slot 9, blade 9-1, iron electrode 10, second cover 11, dephosphorization product discharge port 12, dephosphorization product collection bucket 13; battery bracket 14, shell fixing screws 15, external wires 16, electrical signal acquisition system 17. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with specific drawings and specific embodiments. Unless otherwise specified or conflicting, the preferred embodiments can be combined arbitrarily.

[0035] like Figure 1 and Figure 2 As shown, the device for treating phosphorus-containing wastewater and recovering phosphorus resources with an iron-air battery of the present invention comprises a cathode chamber A and an anode chamber B, a proton exchange membrane 6 is provided between one side of the cathode chamber A and one side of the anode chamber B and is sealed and connected, an air electrode 3 is provided on the other side of the cathode chamber A, a cathode chamber electrolyte circulation system 5 is connected to the cathode chamber A, a wire is connected to the air electrode 3, and the wire extends to the outside of the cathode chamber A; the anode chamber B is provided with an anode chamber water inlet 7, an iron electrode 10 and a dephosphorization product discharge port 12, the dephosphorization product discharge port 12 is located at the bottom of the anode chamber B, the iron electrode 10 is arranged in the anode chamber B, and a wire is connected to the iron electrode 10, and the wire extends to the outside of the anode chamber B.

[0036] As a preferred embodiment of the present invention, Figure 1 to Figure 4As shown, the cathode chamber electrolyte circulation system 5 includes an electrolyte inlet 5-1, a water inlet pipe 5-2, an electrolyte storage tank 5-3, a connecting pipe 5-4, a circulation pump 5-5, a water outlet pipe 5-6 and an electrolyte outlet 5-7. The electrolyte inlet 5-1 is arranged at the lower part of one side of the cathode chamber A, and the electrolyte outlet 5-7 is arranged at the upper part of the other side of the cathode chamber A; the electrolyte inlet 5-1 is connected to the electrolyte storage tank 5-3 through the water inlet pipe 5-2, the water inlet of the circulation pump 5-5 is connected to the electrolyte storage tank 5-3 through the connecting pipe 5-4, and the water outlet of the circulation pump 5-5 is connected to the electrolyte outlet 5-7 through the water outlet pipe 5-6.

[0037] As a preferred embodiment of the present invention, Figure 2 and Figure 5 As shown, an external blade slot 9 is embedded in the upper part of the anode chamber B, and an iron electrode 10 passes through the external blade slot 9 and is suspended in the middle of the anode chamber B. A wire is connected to the upper end of the iron electrode 10; two blades are arranged in the external blade slot 9, and the two blades are arranged in a V shape, and the iron electrode 10 passes through the two blades.

[0038] As a preferred embodiment of the present invention, Figure 1 , Figure 2 and Figure 5 As shown, a dephosphorization product collecting hopper 13 is provided at the bottom of the anode chamber B, and the outlet of the dephosphorization product collecting hopper 13 serves as the dephosphorization product discharge outlet 12.

[0039] As a preferred embodiment of the present invention, Figure 1 and Figure 2 As shown, the wire connected to the air electrode 3 and the wire connected to the iron electrode 10 can be directly connected, or connected to an electrical appliance, or connected to an electric energy collector, or connected to an electrical signal acquisition system 17 .

[0040] In the device for treating phosphorus-containing wastewater and recovering phosphorus resources by the iron-air battery of the present invention, the positive and negative electrodes respectively use an iron electrode and an air electrode with low manufacturing cost, wastewater containing phosphate is added to the anode chamber, and a 1 mol / L sodium chloride solution is added to the cathode chamber as an electrolyte; the cathode and cathode chambers are separated by a proton exchange membrane, and the cathode and cathode are connected by an external wire to form a primary battery system. There is a potential difference between the iron anode and the air cathode, so that the iron anode loses electrons, and the generated ferrous ions react with the phosphate in the anode liquid to generate blue iron ore (Fe3(PO4)2·8H2O); the electrons reach the air cathode via the external wire, and the oxygen in the air is collected by the gas collection layer to reach the catalytic layer. Under the action of the Pt / C catalyst, the oxygen reacts with the electrons received by the cathode to generate water; the protons inside the battery move through the proton exchange membrane to form a loop, and an open circuit voltage of 1.2V can be generated in the external circuit. The device uses ferrous ions generated in situ by iron electrodes as dephosphorization agents, achieving wastewater phosphorus removal without introducing other impurity ions, while also recovering phosphorus resources and electrical energy in the wastewater.

[0041] Example

[0042] like Figure 1 to Figure 5 As shown, the device for treating phosphorus-containing wastewater and recovering phosphorus resources with an iron-air battery in this embodiment includes a cathode chamber A, an anode chamber B and external connection equipment, wherein the cathode chamber A and the anode chamber B are hollow cavities; the cathode chamber A is connected with a hollow plastic cover, a sealing gasket 2, an air electrode 3, an external wire port Ⅰ4 and a cathode chamber electrolyte circulation system 5, and the cathode chamber electrolyte circulation system 5 includes an electrolyte inlet 5-1, a water inlet pipe 5-2, an electrolyte storage tank 5-3, a connecting pipe 5-4, and a circulation pump 5-5 , water outlet pipes 5-6, electrolyte outlets 5-7; the cathode chamber A transfers mass with the anode chamber B via the proton exchange membrane 6, and the cathode chamber A and the anode chamber B are sealed and connected by a sealing gasket 2; the anode chamber B is provided with an anode chamber water inlet 7, an external wire port II 8, an external blade slot 9, an iron electrode 10, a solid plastic cover, a dephosphorization product discharge port 12, and a dephosphorization product collection bucket 13; the external connection equipment includes a battery bracket 14, a shell fixing screws 15, an external wire 16, and an electrical signal acquisition system 17.

[0043] like Figure 1 and Figure 2As shown, the air electrode 3 is arranged on the left side of the inner cavity of the cathode chamber A, the right side of the cathode chamber A is sealed by a hollow plastic cover and a sealing gasket 2, the external wire port Ⅰ4 is arranged on the upper right side of the cathode chamber A, and the cathode chamber electrolyte circulation system 5 is arranged at the bottom of the cathode chamber A; the upper end of the air electrode 3 is connected to the external wire 16; the external wire 16 extends into the cathode chamber through the external wire port Ⅰ4 and is connected to the air electrode 3; the electrolyte inlet 5-1 in the cathode chamber electrolyte circulation system 5 is placed at the bottom of one side of the cathode chamber A, and the electrolyte outlet 5-6 is placed at the top of the other side of the cathode chamber; the electrolyte storage tank 5-3 and the circulation pump 5-4 are placed at the bottom of the device; the electrolyte circulation is completed by connecting the water inlet pipe 5-2, the connecting pipe 5-4, and the water outlet pipe 5-5.

[0044] like Figure 1 and Figure 2 As shown, the anode chamber water inlet 7, the external wire port II8 and the external blade slot 9 are arranged on the top of the anode chamber B, the left side of the anode chamber B is sealed by a sealing gasket 2 and a solid plastic cover, the dephosphorization product collecting bucket 13 is arranged at the lower part of the anode chamber B, and the outlet of the dephosphorization product collecting bucket 13 serves as the dephosphorization product discharge port 12; the external blade slot 9 is embedded in the upper part of the anode chamber B; the iron electrode 10 passes through the external blade slot 9 and is suspended in the middle of the anode chamber, and the upper end of the iron electrode 10 is connected to the external wire 16; the external wire 16 extends into the anode chamber through the external wire port II8 and is connected to the iron electrode 10; the upper end (i.e., the large end) of the dephosphorization product collecting bucket 13 is connected to the reaction zone of the anode chamber.

[0045] The air electrode 3 is connected to the iron electrode 10 through an external wire 16, and an electrical signal acquisition system 17 is provided on the external wire 16; the proton exchange membrane 6 for exchanging substances is placed between the cathode chamber and the anode chamber; the cathode chamber A, the anode chamber B, the sealing gasket 2, the hollow plastic cover and the solid plastic cover are tightened by four fixing screws 15 to form an integral structure, and the bottom of the integral structure is connected to the battery bracket 14 to maintain stability.

[0046] The size and proportion of the above-mentioned components can be set according to actual conditions. In this embodiment, the cathode chamber and the anode chamber have the same specifications and the same volume, and the volume ratio is 1:1. The anode chamber B can be added with 5-1000mg-p / L phosphorus-containing wastewater, and the cathode chamber A uses 1mol / L sodium chloride solution as the electrolyte; the liquid volume in the two anode chambers B and the cathode chamber A is the same, and the liquid volume accounts for 90% of the volume of each chamber. The external blade slot 9 is embedded in the upper part of the anode chamber B, and the blades on both sides form a V-shaped structure, and the inclination angle of each blade is 45°; the two blades have the same specifications, and the ratio of their length to width is 2:1, and the horizontal spacing between the bottom of the blades on both sides is consistent with the thickness of the iron electrode. In the cathode chamber electrolyte circulation system, the distance from the electrolyte inlet to the bottom is 1 / 3 of the total height of the cathode chamber, and the distance from the electrolyte outlet to the bottom is 2 / 3 of the total height of the cathode chamber, and the ratio of the inner diameter of the electrolyte inlet to the electrolyte outlet is 1:1. The iron electrode is a square iron sheet, which is completely immersed in the phosphorus-containing wastewater, and the ratio of its surface area to the volume of the anode chamber is 1cm 2 :3.5cm 3 The air electrode is a small round piece, which is pressed by combining a carbon-based layer, a diffusion layer and a catalyst layer. It is completely immersed in a sodium chloride electrolyte solution, and the ratio of its surface area to the volume of the cathode chamber is 1cm 2 :1.1cm 3 . A dephosphorization product collecting hopper and a dephosphorization product outlet are provided at the bottom of the anode chamber; the dephosphorization product collecting hopper has an inclination angle of 60°, and the inner diameter ratio of the dephosphorization product outlet to the anode chamber water inlet is 1:1; the ratio of the surface area of ​​the dephosphorization product outlet to the volume of the dephosphorization product collecting hopper is 1:3.5, and the height of the dephosphorization product collecting hopper is 1 / 3 of the total height of the anode chamber. The cathode chamber and the anode chamber are connected through a proton exchange membrane to exchange substances between the anion and cation chambers, and the ratio of the surface area of ​​the proton exchange membrane to the volume of the cathode chamber is 1cm 2 :1.1cm 3 The pH of the anolyte is 4 to 9, the redox potential is -300 to -600 mv, the Fe / P is greater than 1.5, and the formation of blue iron ore can be observed in the phosphorus removal product collection bucket and the surface of the iron electrode. After testing, the above-mentioned size ratio and parameters can better achieve the test purpose of the present invention.

[0047] The device for treating phosphorus-containing wastewater and recovering phosphorus resources using the above-mentioned iron-air battery of the present invention can be made of plastic, and the working process is as follows: phosphate-containing wastewater enters the anode chamber from the anode chamber water inlet 7 as the anode liquid; the iron electrode 10 in the anode chamber loses electrons to generate soluble divalent iron, and the divalent iron ions enter the anode liquid and react with the phosphate ions in the anode liquid to generate blue iron ore precipitation; the blue iron ore is collected by the dephosphorization product collection bucket 13 and discharged from the dephosphorization product discharge port 12. The electrons lost by the iron electrode 10 in the anode chamber are transmitted to the air electrode 3 in the cathode chamber via the external wire 16, forming a current in the external circuit, and the data is collected by the electrical signal collection system 17. The sodium chloride solution enters the cathode chamber via the electrolyte inlet 5-1 in the electrolyte circulation system 5 as the cathode liquid, and oxygen enters the cathode chamber as an active substance to act as a power-consuming substance, accepting electrons on the air electrode 3 to generate water. The proton exchange membrane 6 separates the anion chamber and the cation chamber. On the one hand, it maintains the charge balance between the anode chamber and the cathode chamber through proton exchange, and on the other hand, it isolates the oxygen in the cathode chamber to ensure the anaerobic environment of the anode chamber.

[0048] The present invention has the following characteristics:

[0049] 1) Zero-valent iron is cheap and easy to obtain, which reduces the cost of wastewater phosphorus removal; 2) The reaction cycle is short, which not only can efficiently treat phosphorus-containing wastewater, but also can recycle phosphorus resources in the form of blue iron ore; 3) The setting of the electrolyte circulation system and the blade slot ensures its stable power generation performance, and the open circuit voltage can reach 1.2V.

Claims

1. An iron-air battery device for treating phosphorus-containing wastewater and recovering phosphorus resources, characterized in that: It comprises a cathode chamber (A) and an anode chamber (B), wherein a proton exchange membrane (6) is provided between one side of the cathode chamber (A) and one side of the anode chamber (B) and they are sealed and connected, an air electrode (3) is provided on the other side of the cathode chamber (A), a cathode chamber electrolyte circulation system (5) is connected to the cathode chamber (A), and a wire is connected to the air electrode (3), and the wire extends to the outside of the cathode chamber (A); The anode chamber (B) is provided with an anode chamber water inlet (7), an iron electrode (10) and a dephosphorization product outlet (12), wherein the dephosphorization product outlet (12) is located at the bottom of the anode chamber (B), the iron electrode (10) is arranged in the anode chamber (B), and a wire is connected to the iron electrode (10), and the wire extends to the outside of the anode chamber (B); An external blade slot (9) is embedded in the upper part of the anode chamber (B); an iron electrode (10) passes through the external blade slot (9) and is suspended in the middle of the anode chamber (B); a wire is connected to the upper end of the iron electrode (10); two blades are arranged in a V shape between the two blades, and the iron electrode (10) passes through between the two blades; The anode chamber (B) is filled with phosphorus-containing wastewater, the concentration of which is 5-1000 mg-p / L, and the cathode chamber (A) uses a 1-3 mol / L sodium chloride solution as an electrolyte; the iron electrode (10) can lose electrons in the anode chamber (B) to generate soluble divalent iron, and the soluble divalent iron ions enter the phosphorus-containing wastewater and react with phosphate ions in the phosphorus-containing wastewater to generate blue iron ore precipitation; Every 3.5-4cm 3 The anode chamber (B) is configured with 1-1.5cm 2 Iron electrodes (10); each 1.1-1.5 cm 3 The cathode chamber (A) is configured with 1-1.2cm 2 An air electrode (3); Every 1.1-1.5 cm 3 The cathode chamber (A) is configured with 1-1.2cm 2 of proton exchange membrane (6).

2. The device for treating phosphorus-containing wastewater and recovering phosphorus resources by an iron-air battery according to claim 1, characterized in that: The cathode chamber electrolyte circulation system (5) comprises an electrolyte inlet (5-1), a water inlet pipe (5-2), an electrolyte storage tank (5-3), a connecting pipe (5-4), a circulation pump (5-5), a water outlet pipe (5-6) and an electrolyte outlet (5-7). The electrolyte inlet (5-1) is arranged at the lower part of one side of the cathode chamber (A), and the electrolyte outlet (5-7) is arranged at the upper part of the other side of the cathode chamber (A). The electrolyte inlet (5-1) is connected to the electrolyte storage tank (5-3) through the water inlet pipe (5-2), the water inlet of the circulation pump (5-5) is connected to the electrolyte storage tank (5-3) through the connecting pipe (5-4), and the water outlet of the circulation pump (5-5) is connected to the electrolyte outlet (5-7) through the water outlet pipe (5-6).

3. The device for treating phosphorus-containing wastewater and recovering phosphorus resources by an iron-air battery according to claim 2, characterized in that: In the cathode chamber electrolyte circulation system (5), the distance from the electrolyte inlet (5-1) to the bottom is 1 / 3 of the total height of the cathode chamber, the distance from the electrolyte outlet (5-7) to the bottom is 2 / 3 of the total height of the cathode chamber, and the ratio of the inner diameters of the electrolyte inlet (5-1) and the electrolyte outlet (5-7) is 1:

1.

4. The device for treating phosphorus-containing wastewater and recovering phosphorus resources by an iron-air battery according to claim 1, characterized in that: A dephosphorization product collecting hopper (13) is provided at the bottom of the anode chamber (B), and the outlet of the dephosphorization product collecting hopper (13) serves as a dephosphorization product discharge outlet (12).

5. The device for treating phosphorus-containing wastewater and recovering phosphorus resources by an iron-air battery according to claim 1, characterized in that: The volume ratio of the cathode chamber (A) to the anode chamber (B) is 1:

1.

6. A method for treating phosphorus-containing wastewater and recovering phosphorus resources using an iron-air battery, characterized in that: The device according to any one of claims 1 to 5 comprises the following process: The phosphate-containing wastewater is introduced into the anode chamber (B) from the anode chamber water inlet (7) as the anode liquid; Add catholyte into cathode chamber (A); Connecting the wire connected to the iron electrode (10) to the wire connected to the air electrode (3) or to an electrical load; The iron electrode (10) in the anode chamber (B) loses electrons to generate soluble divalent iron, and the soluble divalent iron ions enter the anode liquid and react with the phosphate ions in the anode liquid to generate cyanite precipitation; the cyanite is discharged through the dephosphorization product discharge port (12); The electrons lost by the iron electrode (10) are transferred to the air electrode (3); The cathode liquid accepts electrons at the air electrode (3); The proton exchange membrane (6) separates the anode chamber (B) and the cathode chamber (A), and maintains the charge balance between the anode chamber (B) and the cathode chamber (A) through proton exchange.

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