Stacked electrochemical wastewater separation and recovery device and method

Abstract

The application discloses a stack type electrochemical wastewater separation and recovery device and method in the technical field of resource recovery, which comprises a fixing assembly, an anode assembly and a cathode assembly; n+1 anode assemblies and n cathode assemblies are arranged in the fixing assembly in a spaced distribution mode. Ions and gas generated by the solution of the multistage flow cathode in the n cathode assemblies are exchanged with the solution of the anode in the n+1 anode assemblies through the exchange membrane assembly, so that an alkaline environment is formed in the cathode chamber, metal ions are deposited on the porous cathode plate, and gas is separated out, the gas is dissolved and recovered in the acidic environment in the anode chamber, the recovery liquid is introduced into the cathode chamber when the elementary substance of the metal is recovered, and the gas generated by the ionization of the porous cathode plate forms bubbles at the electrode interface, so that the elementary substance of the metal deposited on the surface of the cathode is desorbed, and the recovery process does not need to rely on organic solvent extraction or strong acid and alkali dissolution.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resource recycling, and particularly relates to a stacked electrochemical wastewater separation and recycling device and method. BACKGROUND

[0002] In the electroplating industry, nickel sulfate is usually used as a raw material, ammonia water is used as a complexing agent, and sodium hydroxide is used as a precipitating agent to stabilize nickel ions in the solution. Ammonia and Ni 2+ form a stable complex (such as [Ni(NH3)6] 2+ ), which can improve the conductivity, dispersion ability, and cathode current efficiency of the plating solution. It can also adjust the pH value of the electrolyte and maintain the stability of the solution. The processes such as cleaning and liquid replacement after electroplating will produce a large amount of wastewater, mainly composed of sodium sulfate, sodium hydroxide, ammonia nitrogen, and heavy metal nickel. At the same time, after nickel and ammonia form a stable complex, it is difficult to completely remove it by traditional chemical precipitation method, and special treatment process (such as breaking the complex) is required, which needs to add a large amount of chemical reagent. In recent years, people's interest in developing and utilizing waste ammonia resources has been growing, so resource recycling can be considered. On the one hand, the recovered by-products can be reused to offset part of the wastewater treatment cost and reduce the overall treatment cost; on the other hand, secondary pollution can be avoided.

[0003] Traditional methods for separating heavy metals include sulfide precipitation and breaking the complex. The sulfide precipitation method refers to a method in which sodium sulfide (or potassium sulfide) is added to the wastewater to make the heavy metal ions in the wastewater react with the sulfur ions to form a difficult-to-dissolve precipitate, which is then filtered and separated. The disadvantage of this process is that the sediment is fine and difficult to settle. The breaking complex method needs to remove ammonia nitrogen first, and then nickel will precipitate in the form of nickel hydroxide in an environment with a pH of about 10, and the nickel element is recovered. However, the traditional method needs to add a large amount of chemical reagent, causing great pollution, is not energy-saving and environmentally friendly, has low treatment efficiency, and has poor use effect. SUMMARY

[0004] The present application aims to provide a stacked electrochemical wastewater separation and recycling device and method to solve the problem of the traditional method needing to add a large amount of chemical reagent, causing great pollution, not being energy-saving and environmentally friendly, and having low treatment efficiency.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] In a first aspect, the present application provides a stacked electrochemical wastewater separation and recycling device, comprising a fixed component, an anode component, and a cathode component:

[0007] The fixed component is installed with n+1 anode components and n cathode components distributed at intervals, an exchange membrane component is installed between the anode component and the cathode component, and the anode component and the cathode component are connected to a power supply component.

[0008] The anode assembly comprises n+1 anode chambers and porous anode plates, the anode chambers are provided with anode chambers, n anode chambers are fixedly installed with porous anode plates, the cathode assembly comprises n cathode chambers and porous cathode plates, the cathode chambers are provided with cathode chambers, the cathode chambers are fixedly installed with porous cathode plates, and the power supply assembly is electrically connected with the porous anode plates and the porous cathode plates;

[0009] In use, the power supply assembly supplies power to the porous anode plates and the porous cathode plates to electrolyze the corresponding solution, the exchange membrane assembly exchanges ions and gas to deposit metal ions on the porous cathode plates, the cathode chamber is then filled with a recovery solution, and the porous cathode plates are used to precipitate gas to widen the interface gap between the metal and the porous cathode plates, and the recovery solution is used to flow to recover the metal.

[0010] As a further scheme of the present application, one side of the n cathode chambers is connected with a cathode water inlet pipe, the other side of the n cathode chambers is connected with a first cathode water outlet pipe, the upper end of the cathode chamber is connected with a telescopic chamber, the cathode chamber is communicated with the telescopic chamber, the upper end of the telescopic chamber is connected with a pressing plate, the upper end of the cathode chamber is fixedly connected with a limiting plate, the pressing plate is clamped in the limiting plate, and the telescopic chamber is used to store gas elastically.

[0011] As a further scheme of the present application, the bottom end of the cathode chamber is welded with a bottom chamber, the bottom end of the bottom chamber is connected with a second cathode water outlet pipe, the second cathode water outlet pipe is connected with the first cathode water outlet pipe, and the second cathode water outlet pipe and the first cathode water outlet pipe are both connected with valves.

[0012] As a further scheme of the present application, the n+1 anode chambers and the n cathode chambers are sequentially and spacedly distributed and installed with exchange membrane assemblies, one side of the n anode chambers is connected with an anode water inlet pipe, the other side of the anode chamber is connected with an anode backflow pipe, the anode backflow pipe is connected with a one-way valve and the anode water inlet pipe, the other side of the n+1 anode chambers is connected with an anode water outlet pipe, both ends of the n+1 anode chambers are connected with end plates, the end plates are contact-connected with a fixing assembly, and the anode backflow pipe is used to circulate and backflow the solution in the anode chamber.

[0013] As a further scheme of the present application, the n+1 anode chambers and the n cathode chambers are both installed with flow guide lining nets, and the flow guide lining nets are used to guide the flow of the solution.

[0014] As a further scheme of the present application, the exchange membrane assembly comprises anion exchange membranes and hydrophobic gas membranes, the anion exchange membranes and the hydrophobic gas membranes are alternately and sequentially installed between the n+1 anode chambers and the n cathode chambers, the anion exchange membranes are used to exchange ions, and the hydrophobic gas membranes are used to exchange gas.

[0015] As a further scheme of the present application: the power supply assembly comprises a power supply, positive and negative poles of the power supply are connected with the anode terminal wire and the cathode terminal wire respectively, the anode terminal wire penetrates through the anode chamber and is connected with the porous anode plate, and the cathode terminal wire penetrates through the cathode chamber and is connected with the porous cathode plate.

[0016] As a further scheme of the present application: the fixing assembly comprises a fixing plate and a screw rod, the fixing plate is connected with one side of the end plate in a fit manner, and the screw rod is connected with both ends of the fixing plate, and the fixing plate and the screw rod are used for tightly connecting the n+1 anode chambers and the n cathode chambers.

[0017] In a first aspect, the present application provides a stacked electrochemical wastewater separation and recovery method, which comprises:

[0018] The solution of the anode is introduced into the anode chamber of the anode assembly, the solution of the cathode is introduced into the cathode chamber of the cathode assembly, and the solutions of the anode and the cathode are multi-stage flowed, wherein the solution of the anode is circulated flowed in the anode chamber;

[0019] The power supply assembly is started, the porous anode plate and the porous cathode plate are powered respectively, and the solutions of the anode and the cathode are electrolyzed to generate ions and gases, the ions and the gases are exchanged between the anode chamber and the cathode chamber through the exchange membrane assembly, so that the metal ions are deposited on the porous cathode plate;

[0020] The recovery solution is introduced into the cathode chamber, and the power supply assembly is started, the porous cathode plate releases the gas to widen the interface gap between the metal element and the porous cathode plate, and the recovery solution is used to flow the metal element.

[0021] As a further scheme of the present application: the residence time of the solution of the anode in the anode chamber is 10 min-60 min, and the residence time of the solution of the cathode in the cathode chamber is 100 min-200 min;

[0022] The current density of the power supply assembly is 50 A m -2 -100A m -2 .

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] 1. In the application, the corresponding anode solution and cathode solution are subjected to multistage electrolysis through multistage anode assemblies and cathode assemblies, the ions and gas generated by the multistage flow cathode solution in the n cathode assemblies are exchanged with the anode solution in the n+1 anode assemblies through the exchange membrane assembly, thereby forming an alkaline environment in the cathode chamber, allowing metal ions to deposit on the porous cathode plate and generate gas, and the gas is dissolved in the acidic environment in the anode chamber for recovery, and when recovering the metal element, the recovery liquid is introduced into the cathode chamber, and the gas generated by the ionization of the porous cathode plate forms bubbles at the electrode interface, thereby desorbing the metal element deposited on the cathode surface, and the recovery process does not rely on organic solvent extraction or strong acid and alkali dissolution, and the recovery rate of the elements in the wastewater is maximized, the treatment efficiency is high, and energy saving and environmental protection are achieved.

[0025] 2. In the application, when the solution in the cathode chamber is ionized, more gas is generated in the cathode chamber of the cathode chamber, and when the generated gas exceeds the upper limit of the gas exchange amount of the hydrophobic gas film in the exchange membrane assembly, the gas is contained through the telescopic chamber to avoid the destruction of the anion exchange membrane and the hydrophobic gas film in the exchange membrane assembly due to the high gas pressure in the cathode chamber caused by too much gas, realize the buffering of the gas, ensure the stable operation of the whole device, and the pressure plate is integrally pressed on the upper end of the telescopic chamber, so that the telescopic chamber maintains a stable gas pressure, ensures the stable gas exchange of the gas through the hydrophobic gas film in the exchange membrane assembly, ensures the overall wastewater treatment efficiency of the device, and has good use effect. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of the three-dimensional structure of the application;

[0027] Figure 2 is a schematic diagram of the three-dimensional structure of the application from the shaft side;

[0028] Figure 3 is a schematic diagram of the three-dimensional structure of the application from the bottom;

[0029] Figure 4 is a schematic diagram of the overall explosion structure of the application;

[0030] Figure 5 is a schematic diagram of the side view structure of the application;

[0031] Figure 6 is a schematic diagram of the Figure 5 is a schematic diagram of the cross-sectional structure at A-A in the application;

[0032] Figure 7 is a schematic diagram of the multistage connection in the second embodiment of the application.

[0033] In the figure: 1, fixed assembly; 11, fixed plate; 12, screw rod; 2, anode assembly; 21, anode chamber; 22, end plate; 23, porous anode plate; 24, flow guide lining net; 25, anode water inlet pipe; 26, anode water outlet pipe; 27, anode backflow pipe; 28, one-way valve; 3, cathode assembly; 31, cathode chamber; 32, porous cathode plate; 33, cathode water inlet pipe; 34, first cathode water outlet pipe; 35, bottom chamber; 36, second cathode water outlet pipe; 37, telescopic chamber; 38, pressing plate; 39, limiting plate; 4, exchange membrane assembly; 41, anion exchange membrane; 42, hydrophobic gas membrane; 5, power supply assembly; 51, power supply; 52, anode terminal wire; 53, cathode terminal wire. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0035] Embodiment one:

[0036] In the electroplating industry, sulfuric acid nickel is usually used as raw material, ammonia water is used as complexing agent, and sodium hydroxide is used as precipitating agent. Electrochemical technology has the advantages of simple operation, strong controllability, economic applicability, mild reaction conditions, etc. In recent years, electrochemical separation in the field of ammonia recovery is becoming more and more popular. It can convert NH4 + into NH (3g) directly through in-situ electrochemical reaction. Specifically, for nickel-ammonia wastewater, nickel-ammonia complex is first broken in the cathode chamber, and NH4 + is dissociated. NH4 + is converted to NH (3g) in an alkaline environment while diffusing into the anode chamber as a gas, realizing efficient recovery of ammonia nitrogen. OH - is generated in the cathode through electrochemical reaction, and the pH in the cathode chamber is increased to about 12 to break the nickel-ammonia complex. At the same time, NH4 + in the solution will be converted to NH (3g) in an alkaline environment and diffuse to the anode chamber through the hydrophobic gas stripping membrane to be captured. The broken nickel ions will be deposited on the cathode, so as to achieve simultaneous utilization of cathode alkali production and anode acid production for ammonia recovery. Nickel is enriched by electrodeposition to realize the whole process of reclamation of nickel and ammonia without adding reagents.

[0037] In this embodiment, as Figures 1-6As shown, the present application provides a stacked electrochemical wastewater separation and recovery device, comprising a fixed assembly 1, an anode assembly 2 and a cathode assembly 3: n+1 anode assemblies 2 and n cathode assemblies 3 are arranged in the fixed assembly 1, an exchange film assembly 4 is arranged between the anode assembly 2 and the cathode assembly 3, and the anode assembly 2 and the cathode assembly 3 are connected to a power supply assembly 5; the anode assembly 2 comprises n+1 anode chambers 21 and a porous anode plate 23, the anode chamber 21 is provided with an anode cavity, and the n anode cavities are fixedly provided with the porous anode plate 23; the cathode assembly 3 comprises n cathode chambers 31 and a porous cathode plate 32, the cathode chamber 31 is provided with a cathode cavity, and the cathode cavity is fixedly provided with the porous cathode plate 32; and the power supply assembly 5 is electrically connected to the porous anode plate 23 and the porous cathode plate 32.

[0038] In use, the power supply assembly 5 supplies power to the porous anode plate 23 and the porous cathode plate 32 to electrolyze the corresponding solutions, the exchange film assembly 4 exchanges ions and gases, so that the metal ions are deposited on the porous cathode plate 32, the recovery solution is introduced into the cathode cavity, and the gas is precipitated on the porous cathode plate 32 to widen the interface gap between the metal element and the porous cathode plate 32, and the recovery solution is used to flow the recovered metal element.

[0039] Specifically, in the present application, the power supply assembly 5 provides power, the multi-stage anode assembly 2 and the cathode assembly 3 allow the corresponding anode solution and the cathode solution to be subjected to multi-stage electrolysis, the ions and gases generated by the multi-stage flow of the cathode solution in the n cathode assemblies 3 are exchanged with the anode solution in the n+1 anode assemblies 2 through the exchange film assembly 4, thereby forming an alkaline environment in the cathode cavity, allowing the metal ions to be deposited on the porous cathode plate 32 and to precipitate gas, and the gas is dissolved in the acidic environment in the anode cavity for recovery, and when recovering the metal element, the recovery liquid is introduced into the cathode cavity, and the gas generated by the ionization of the porous cathode plate 32 forms bubbles at the electrode interface, thereby desorbing the metal element deposited on the cathode surface, and the recovery process does not rely on organic solvent extraction or strong acid and alkali dissolution, so that the recovery rate of the elements recovered from the wastewater is maximized, the treatment efficiency is high, and energy saving and environmental protection are achieved.

[0040] In the present application, the solution input into the cathode assembly 3 is nickel ammonia wastewater, and the ammonia nitrogen concentration is 2000 mg / L-7000 mg / L, for example, it can be 2000 mg / L, 3000 mg / L, 4000 mg / L, 5000 mg / L, 6000 mg / L or 7000 mg / L, more preferably 3000 mg / L-4000 mg / L; the ammonia nitrogen concentration in the present application is calculated based on N element. The nickel ion concentration is generally 50 mg / L-200 mg / L, for example, it can be 50 mg / L, 100 mg / L, 150 mg / L or 200 mg / L, more preferably 150 mg / L-200 mg / L. Among them, according to the actual wastewater situation, the ammonia nitrogen concentration should be more than ten times higher than the nickel ion concentration, and the tap water or deionized water or any one of 0 M-1 M of sulfuric acid, hydrochloric acid or nitric acid added therein is input into the anode assembly 2.

[0041] Further, through the stacked design, the anode assembly 2 and the cathode assembly 3 can be arranged compactly, greatly saving the equipment area and improving the space utilization. At the same time, the modular anode assembly 2 and the cathode assembly 3 are easy to expand and maintain, and the number of assemblies can be flexibly adjusted according to actual needs to meet the needs of different scales and processing capacity.

[0042] Further, the porous stable anode can use a porous metal mesh or a porous foam metal material composed of a ruthenium-iridium alloy, a ruthenium-tantalum alloy, and an iridium-tantalum alloy, and the weaving density parameter range is 30-300 meshes. The porous cathode is selected from any type of porous metal mesh or foam metal material, also subject to the requirement of 30-300 weaving density, and the use of the porous anode plate 23 and the porous cathode plate 32 increases the contact area of the electrode and the wastewater and improves the electrolysis efficiency. In addition, the porous structure is also beneficial to the precipitation and exchange of ions and the precipitation and recovery process of metal ions.

[0043] In use, the power supply assembly 5 supplies power to the porous anode plate 23 and the porous cathode plate 32 to electrolyze the corresponding solution, and the ion and gas exchange film assembly 4 is used to exchange ions and gas, so that metal ions are deposited on the porous cathode plate 32. Then the recovery solution is input into the cathode chamber, and the gas is precipitated on the porous cathode plate 32 to widen the interface gap between the metal element and the porous cathode plate 32, facilitating the flow of the recovery solution to recover the metal element. The whole treatment process is efficient, environmentally friendly and easy to operate, and provides a new solution for the wastewater treatment and resource recovery field.

[0044] Preferably, as Figures 1-6As shown, one side of the n cathode chamber 31 is connected with a cathode water inlet pipe 33, the other side of the n cathode chamber 31 is connected with a first cathode water outlet pipe 34, the upper end of the cathode chamber 31 is connected with a telescopic expansion chamber 37, the cathode chamber communicates with the expansion chamber 37, the upper end of the expansion chamber 37 is connected with a pressing plate 38, the upper end of the cathode chamber 31 is fixedly connected with a limiting plate 39, the pressing plate 38 is clamped in the limiting plate 39, and the expansion chamber 37 is used to store gas elastically.

[0045] Specifically, when the cathode chamber 31 ionizes the solution, more gas is generated in the cathode chamber of the cathode chamber 31. When the generated gas exceeds the upper limit of the gas exchange amount of the hydrophobic gas film 42 in the exchange membrane assembly 4, the telescopic expansion chamber 37 is used to accommodate the gas, so as to avoid the destruction of the anion exchange membrane 41 and the hydrophobic gas film 42 in the exchange membrane assembly 4 due to the high gas pressure in the cathode chamber, realize the buffering of the gas, ensure the stable operation of the whole device, stabilize the reaction voltage, avoid unnecessary energy consumption, and the pressing plate 38 is integrally pressed on the upper end of the expansion chamber 37, so that the gas pressure in the expansion chamber 37 is kept stable, the gas exchange through the hydrophobic gas film 42 in the exchange membrane assembly 4 is ensured, the overall wastewater treatment efficiency of the device is ensured, and the use effect is good.

[0046] Preferably, as shown in the drawings, Figure 3 As shown, the bottom end of the cathode chamber 31 is welded with a bottom chamber 35, the bottom end of the bottom chamber 35 is connected with a second cathode water outlet pipe 36, the second cathode water outlet pipe 36 is connected with the first cathode water outlet pipe 34, and the second cathode water outlet pipe 36 and the first cathode water outlet pipe 34 are both connected with valves.

[0047] Specifically, the bottom of the cathode chamber 31 is connected with the bottom chamber 35, the bottom chamber 35 is connected with the second cathode water outlet pipe 36, the valve on the first cathode water outlet pipe 34 is opened and the valve on the second cathode water outlet pipe 36 is closed during the process of depositing the metal element porous cathode plate 32, so as to facilitate the fluid to be discharged from one side of the cathode chamber 31 and ensure the overall horizontal flow direction of the fluid in the device. When the metal element is recovered, the valve on the second cathode water outlet pipe 36 is opened and the valve on the first cathode water outlet pipe 34 is closed, so that the bottom of the bottom chamber 35 facilitates the deposition of the peeled metal element and allows the metal element to be quickly discharged through the recovery liquid. The metal element recovery effect is good, and the metal element is prevented from accumulating in the cathode chamber. The metal element recovery effect is good.

[0048] Preferably, as shown in the drawings, Figures 1-6As shown, n+1 anode chambers 21 and n cathode chambers 31 are arranged in sequence with exchange membrane assemblies 4 installed, one side of n anode chambers 21 is connected to anode water inlet pipe 25, the other side of one anode chamber 21 is connected to anode backflow pipe 27, one-way valve 28 is connected to anode backflow pipe 27 and anode water inlet pipe 25, the other side of n+1 anode chambers 21 is connected to anode water outlet pipe 26, both ends of n+1 anode chambers 21 are connected to end plate 22, end plate 22 is connected to fixed assembly 1, anode backflow pipe 27 is used for circulating backflow of solution in anode chamber.

[0049] Specifically, the solution in the anode chamber can be circulated back through the anode backflow pipe 27, which enhances the uniformity of the solution and helps to improve the electrolysis efficiency. The arrangement of one-way valve 28 ensures that the solution does not flow backward during the backflow process, maintaining the one-way flow of the fluid and further improving the stability and reliability of the system. n+1 anode chambers 21 are connected in this way to form a complete anode chamber system, each anode chamber 21 can independently circulate the solution, without interfering with each other, thereby improving the processing capacity and efficiency of the entire electrolysis device. At the same time, the end plate 22 connected to both ends of the anode chamber 21 not only plays a role in fixing and supporting, but also connects to the fixed assembly 1, making the structure of the entire electrolysis device more stable and able to withstand greater working pressure and fluid impact force.

[0050] Preferably, as shown in Figure 4 and Figure 6 n+1 anode chambers 21 and n cathode chambers 31 are installed with flow guide lining 24, which is used for guiding the flow of the solution.

[0051] Specifically, the design of flow guide lining 24 makes the flow of the solution in the anode chamber 21 and the cathode chamber 31 more orderly and efficient, reducing the turbulence and dead zones of the fluid, thereby improving the uniformity and rate of the electrolysis reaction. Through the guidance of flow guide lining 24, the solution can more fully contact the porous anode plate 23 and the porous cathode plate 32, promoting the electrolysis process. In addition, flow guide lining 24 also has a filtering effect, which can block large particles in the solution, protecting the porous anode plate 23 and the porous cathode plate 32 from wear and tear, prolonging the service life of the electrolysis device. n+1 anode chambers 21 and n cathode chambers 31 are installed with flow guide lining 24, ensuring uniform flow of the solution in the entire electrolysis device, further improving the electrolysis efficiency and device performance.

[0052] Preferably, as shown in Figures 1-6As shown, the exchange membrane assembly 4 includes anion exchange membranes 41 and hydrophobic gas membranes 42, which are alternately installed between n+1 anode chambers 21 and n cathode chambers 31. The anion exchange membranes 41 are used for ion exchange, and the hydrophobic gas membranes 42 are used for gas exchange.

[0053] Specifically, the hydrophobic gas membranes 42 have excellent gas permeability and water resistance, which can effectively prevent water from penetrating into other parts of the electrolysis device while allowing gas to pass freely. This design allows the gas generated during electrolysis to be discharged in a timely manner, avoiding the accumulation of gas in the electrolysis chamber, thereby ensuring the smooth progress of the electrolysis process. The alternating installation of the anion exchange membranes 41 and the hydrophobic gas membranes 42 not only achieves effective separation and exchange of ions and gas, but also enhances the structural stability and operational reliability of the electrolysis device. Through the careful design of the exchange membrane assembly 4, the performance of the entire electrolysis device has been significantly improved, which can meet the needs of various complex application scenarios.

[0054] Further, the material of the hydrophobic gas membrane includes any one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or polypropylene (PP).

[0055] In the process of the solution in the cathode passing through the cathode flow-through chamber composed of the anion exchange membranes 41 and the hydrophobic gas membranes 42, NH4 + is converted to NH - in the alkaline environment generated by the OH (3g) in the cathode, and then NH (3g) diffuses to the other side of the hydrophobic gas membrane, which is the anode flow-through chamber composed of the hydrophobic gas membrane and the next layer of anion exchange membrane 41; the nickel-ammonia complex [Ni(NH3)6] 2+ undergoes complex breakdown in a high-pH environment, and Ni 2+ is dissociated and moves to the surface of the cathode under the action of the electric field and undergoes reduction, depositing on the surface of the cathode.

[0056] A large amount of H+ is generated through the electrochemical reaction of the anode, reducing the pH value of the anode liquid, thereby absorbing NH (3g) diffused from the cathode flow-through chamber to the anode flow-through chamber, and finally the ammonia nitrogen is recovered in the form of ammonium salt, which can be ammonium sulfate, ammonium chloride, and ammonium nitrate, etc., depending on the ions present in the original solution, such as SO4 2- , Cl - , NO3 - , etc., corresponding to ammonium sulfate, ammonium chloride, and ammonium nitrate, etc.

[0057] Preferably, as Figure 2 and Figure 3As shown, the power supply assembly 5 includes a power source 51, the positive and negative poles of which are connected to the anode terminal wire 52 and the cathode terminal wire 53 respectively, the anode terminal wire 52 penetrates through the anode chamber 21 and connects the porous anode plate 23, and the cathode terminal wire 53 penetrates through the cathode chamber 31 and connects the porous cathode plate 32.

[0058] Specifically, the porous anode plate 23 and the porous cathode plate 32 serve as the anode and the cathode of the electrochemical reaction respectively, and their design can effectively increase the contact area between the electrode and the solution, thereby improving the efficiency of the electrochemical reaction. The direct current provided by the power source 51 is conducted to the porous anode plate 23 and the porous cathode plate 32 through the anode terminal wire 52 and the cathode terminal wire 53 respectively, forming a current loop to drive the electrochemical reaction in the ammonia-nitrogen recovery process described above. In addition, the materials of the anode terminal wire 52 and the cathode terminal wire 53 need to have good electrical conductivity and corrosion resistance to ensure long-term stable electrochemical reaction.

[0059] Preferably, as shown in Figure 2 As shown, the fixing assembly 1 includes a fixing plate 11 and a screw rod 12, the fixing plate 11 is attached to one side of the end plate 22, and the screw rod 12 is connected at both ends of the fixing plate 11, and the fixing plate 11 and the screw rod 12 are used to tightly connect the n+1 anode chambers 21 and the n cathode chambers 31.

[0060] Specifically, the end of the screw rod 12 is equipped with a nut, and the connection between the fixing plate 11 and the end plate 22 is tightened by rotating the nut to ensure the stability of the entire electrolytic cell. In addition, the design of the fixing plate 11 can be adjusted according to the actual size of the anode chamber 21 and the cathode chamber 31 to ensure good adaptability and sealing to prevent solution leakage during electrolysis.

[0061] Further, as shown in Figure 4 As shown, a sealing strip is embedded and connected between the anode chamber 21, the end plate 22, the cathode chamber 31, the anion exchange membrane 41 and the hydrophobic gas membrane 42, which is made of elastic material such as rubber or silicone to ensure the tight connection between the components. The design of the sealing strip can effectively prevent the leakage of gas or solution generated during electrolysis, and maintain the stability of the pressure and solution concentration inside the electrolytic cell. At the same time, the sealing strip also has certain corrosion resistance, which can adapt to the complex chemical environment in the electrolytic cell and prolong the service life of the electrolytic cell. In addition, the embedded connection of the sealing strip is simple and fast, which is convenient for the assembly and maintenance of the electrolytic cell.

[0062] Example Two:

[0063] As shown in Figure 6As shown, in order to ensure the complete separation and recovery of heavy metal nickel and ammonia nitrogen, and improve the water quality of the effluent at the outlet, the device is provided with multiple stages, preferably two stages. The first cathode effluent pipe 34 of the front stage device is connected to the cathode water inlet pipe 33 of the rear stage device, and the devices are combined to treat wastewater through two-stage devices to ensure that the final effluent quality meets the wastewater discharge standard.

[0064] Further, as shown in the multi-stage device connection, the anode effluent pipe 26 of the front stage device is connected to the anode water inlet pipe 25 of the rear stage device, and they share a liquid supply device. Figure 6

[0065] The liquid supply device provides the required electrolyte for the multi-stage device. Through the connection of the anode effluent pipe 26 and the anode water inlet pipe 25, the electrolyte is recycled. This connection method not only improves the utilization efficiency of the electrolyte, but also ensures the continuity and stability of wastewater treatment between the multi-stage devices. At the same time, sharing a liquid supply device simplifies the system structure, reduces equipment cost and maintenance difficulty.

[0066] Further (not shown in the figure), in the multi-stage device connection, the anode water inlet pipe 25 and the anode effluent pipe 26 of the corresponding device are respectively connected to the liquid supply device for multi-stage independent liquid supply.

[0067] This way can ensure that each stage device can obtain the appropriate amount of electrolyte, so as to avoid the poor wastewater treatment effect caused by insufficient or excessive electrolyte. The design of multi-stage independent liquid supply can also make the treatment effect of each stage device more stable, and will not affect the efficiency and quality of wastewater treatment due to the change of electrolyte concentration. In addition, multi-stage independent liquid supply is also helpful to realize more refined wastewater treatment control, which can adjust the supply amount of electrolyte according to the processing needs of each stage device, further improve the efficiency of wastewater treatment and the quality of effluent.

[0068] Among them, the recovery operation period of the rear stage device can be shorter than that of the front stage device.

[0069] Specifically, in the process of hydrogen evolution reaction when recovering nickel, a large amount of H2 bubbles will be generated at the interface between the nickel layer and the electrode plate, thereby widening the interface gap and facilitating separation.

[0070] If it is oxygen evolution reaction when recovering nickel, a large amount of O2 bubbles will be generated at the interface, which can also widen the interface gap and facilitate separation. In addition, the acidic environment generated by oxygen evolution reaction can also loosen the nickel layer deposited on the surface of the electrode to some extent, and strengthen the desorption effect.

[0071] A stack type electrochemical wastewater separation and recovery method, the method comprises:

[0072] ​The solution of the anode is introduced into the anode chamber of the anode assembly 2, the solution of the cathode is introduced into the cathode chamber of the cathode assembly 3, and the solution of the anode and the solution of the cathode are multi-stage flowed, wherein the solution of the anode is circulated flowed in the anode chamber;

[0073] The power supply assembly 5 is started, and the porous anode plate 23 and the porous cathode plate 32 are powered respectively, and the solution of the anode and the solution of the cathode are electrolyzed and ions and gases are generated, the ions and the gases are exchanged between the anode chamber and the cathode chamber through the exchange membrane assembly 4, so that the metal ions are deposited on the porous cathode plate 32;

[0074] The recovery solution is introduced into the cathode chamber, and the power supply assembly 5 is started, and the porous cathode plate 32 releases the gas to widen the interface gap between the metal element and the porous cathode plate 32, and the recovery solution is used to flow the metal element.

[0075] When the recovery operation is performed, the solution of the cathode is emptied, and the recovery solution is introduced into the cathode chamber again, and the recovery solution can be circulated flowed, and the residence time of the recovery solution in the cathode flow chamber is 10 min-60 min, for example, it can be 10 min, 20 min, 40 min, 60 min, and more preferably 10 min-20 min, so as to prevent the desorbed nickel particles from blocking the flow channel.

[0076] The recovery solution is tap water or deionized water, and the recovery solution can also be sodium sulfate, potassium sulfate or other salt solutions which are stable under the power-on state, have good conductivity and do not react with nickel, and the concentration is generally not higher than 0.5 M.

[0077] Preferably (not shown in the figure), the residence time of the solution of the anode in the anode chamber is 10 min-60 min; it can be 10 min, 20 min, 40 min, 60 min, and more preferably 10 min-30 min, and the anode solution is circulated flowed, and the ammonia is enriched in the anode;

[0078] The residence time of the solution of the cathode in the cathode chamber is 100 min-200 min; it can be 100 min, 120 min, 140 min, 160 min, 180 min, and more preferably 120 min-180 min, and the cathode solution is continuously flowed;

[0079] The current density of the power supply assembly 5 is 50 Am -2 -100 Am -2 , it can be 50 Am -2 , 60 Am -2 , 80 Am -2 , 100 Am -2 , and more preferably 80 Am -2- 90Am -2 .

[0080] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacements or changes according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A stacked electrochemical wastewater separation and recovery device, characterized in that, It comprises a fixed assembly (1), an anode assembly (2) and a cathode assembly (3): The fixed assembly (1) is internally installed with n+1 anode assemblies (2) and n cathode assemblies (3) which are spacedly distributed, an exchange film assembly (4) is installed between the anode assembly (2) and the cathode assembly (3), and the anode assembly (2) and the cathode assembly (3) are connected with a power supply assembly (5); The anode assembly (2) comprises n+1 anode chambers (21) and a porous anode plate (23), the anode chamber (21) is provided with an anode chamber, and n anode chambers (21) are fixedly installed with the porous anode plate (23), the cathode assembly (3) comprises n cathode chambers (31) and a porous cathode plate (32), the cathode chamber (31) is provided with a cathode chamber, and the cathode chamber is fixedly installed with the porous cathode plate (32), the power supply assembly (5) is electrically connected with the porous anode plate (23) and the porous cathode plate (32); one side of each of the n cathode chambers (31) is connected with a cathode water inlet pipe (33), the other side of each of the n cathode chambers (31) is connected with a first cathode water outlet pipe (34), the upper end of the cathode chamber (31) is connected with a telescopic expansion chamber (37), the cathode chamber is communicated with the expansion chamber (37), the upper end of the expansion chamber (37) is connected with a pressing plate (38), the upper end of the cathode chamber (31) is fixedly connected with a limiting plate (39), the pressing plate (38) is clamped in the limiting plate (39), and the expansion chamber (37) is used for elastically expanding and storing gas; In use, the power supply assembly (5) supplies power to the porous anode plate (23) and the porous cathode plate (32) to electrolyze corresponding solutions, the exchange film assembly (4) is used for exchanging ions and gas, so that metal ions are deposited on the porous cathode plate (32), the cathode chamber is filled with a recovery solution, and gas is precipitated on the porous cathode plate (32), so as to widen the interface gap between the metal element and the porous cathode plate (32), and the recovery solution is used for flowing recovery of the metal element.

2. The stacked electrochemical wastewater separation and recovery device according to claim 1, characterized in that: The bottom end of the cathode chamber (31) is welded with a bottom chamber (35), the bottom end of the bottom chamber (35) is connected with a second cathode water outlet pipe (36), the second cathode water outlet pipe (36) is connected with the first cathode water outlet pipe (34), and the second cathode water outlet pipe (36) and the first cathode water outlet pipe (34) are both connected with valves.

3. The stacked electrochemical wastewater separation and recovery device according to claim 2, characterized in that: n+1 anode chambers (21) and n cathode chambers (31) are sequentially and spacedly distributed and installed with exchange film assemblies (4), one side of each of the n anode chambers (21) is connected with an anode water inlet pipe (25), one side of the other anode chamber (21) is connected with an anode backflow pipe (27), the anode backflow pipe (27) is connected with a one-way valve (28) and the anode water inlet pipe (25), the other side of each of the n+1 anode chambers (21) is connected with an anode water outlet pipe (26), both ends of each of the n+1 anode chambers (21) are connected with end plates (22), the end plates (22) are in contact and connected with the fixed assembly (1), and the anode backflow pipe (27) is used for circulating backflow of the solution in the anode chamber.

4. The stacked electrochemical wastewater separation and recovery device according to claim 3, characterized in that: The n+1 anode chambers (21) and n cathode chambers (31) are each provided with a flow guide lining (24) for guiding the flow of solution.

5. The stacked electrochemical wastewater separation and recovery device according to claim 4, characterized in that: The exchange membrane assembly (4) comprises an anion exchange membrane (41) and a hydrophobic gas membrane (42), which are alternately installed between the n+1 anode chambers (21) and n cathode chambers (31), the anion exchange membrane (41) is used for exchanging ions, and the hydrophobic gas membrane (42) is used for exchanging gas.

6. The stacked electrochemical wastewater separation and recovery device according to claim 5, characterized in that: The power supply assembly (5) comprises a power supply (51), the positive and negative electrodes of the power supply (51) are connected to an anode terminal line (52) and a cathode terminal line (53) respectively, the anode terminal line (52) penetrates the anode chamber (21) and is connected to the porous anode plate (23), and the cathode terminal line (53) penetrates the cathode chamber (31) and is connected to the porous cathode plate (32).

7. The stacked electrochemical wastewater separation and recovery device according to claim 6, characterized in that: The fixing assembly (1) comprises a fixing plate (11) and a screw rod (12), the fixing plate (11) is attached to one side of the end plate (22), and the two ends of the fixing plate (11) are penetrated and connected with the screw rod (12), and the fixing plate (11) and the screw rod (12) are used for tightly connecting the n+1 anode chambers (21) and n cathode chambers (31).

8. A stacked electrochemical wastewater separation and recovery method applied to the device of any one of claims 1-6, characterized in that, The method comprises: The solution of the anode is introduced into the anode chamber of the anode assembly (2), the solution of the cathode is introduced into the cathode chamber of the cathode assembly (3), and the solution of the anode and the solution of the cathode are multi-stage flowed, wherein the solution of the anode is circulated flowed in the anode chamber; The power supply assembly (5) is started, the porous anode plate (23) and the porous cathode plate (32) are powered respectively, the solution of the anode and the solution of the cathode are electrolyzed to generate ions and gas, and the ions and gas are exchanged between the anode chamber and the cathode chamber through the exchange membrane assembly (4) to make the metal ions deposited on the porous cathode plate (32); The recovery solution is introduced into the cathode chamber, and the power supply assembly (5) is started, the porous cathode plate (32) releases gas to widen the interface gap between the metal element and the porous cathode plate (32), and the recovery solution is used to flow and recover the metal element. The n+1 anode chambers (21) and n cathode chambers (31) are each provided with a flow guide lining (24) for guiding the flow of solution. The exchange membrane assembly (4) comprises an anion exchange membrane (41) and a hydrophobic gas membrane (42), which are alternately installed between the n+1 anode chambers (21) and n cathode chambers (31), the anion exchange membrane (41) is used for exchanging ions, and the hydrophobic gas membrane (42) is used for exchanging gas. The power supply assembly (5) comprises a power supply (51), the positive and negative electrodes of the power supply (51) are connected to an anode terminal line (52) and a cathode terminal line (53) respectively, the anode terminal line (52) penetrates the anode chamber (21) and is connected to the porous anode plate (23), and the cathode terminal line (53) penetrates the cathode chamber (31) and is connected to the porous cathode plate (32). The fixing assembly (1) comprises a fixing plate (11) and a screw rod (12), the fixing plate (11) is attached to one side of the end plate (22), and the two ends of the fixing plate (11) are penetrated and connected with the screw rod (12), and the fixing plate (11) and the screw rod (12) are used for tightly connecting the n+1 anode chambers (21) and n cathode chambers (31). The method comprises: The solution of the anode is introduced into the anode chamber of the anode assembly (2), the solution of the cathode is introduced into the cathode chamber of the cathode assembly (3), and the solution of the anode and the solution of the cathode are multi-stage flowed, wherein the solution of the anode is circulated flowed in the anode chamber; The power supply assembly (5) is started, the porous anode plate (23) and the porous cathode plate (32) are powered respectively, the solution of the anode and the solution of the cathode are electrolyzed to generate ions and gas, and the ions and gas are exchanged between the anode chamber and the cathode chamber through the exchange membrane assembly (4) to make the metal ions deposited on the porous cathode plate (32); The recovery solution is introduced into the cathode chamber, and the power supply assembly (5) is started, the porous cathode plate (32) releases gas to widen the interface gap between the metal element and the porous cathode plate (32), and the recovery solution is used to flow and recover the metal element.

9. The stacked electrochemical wastewater separation and recovery method according to claim 8, characterized in that: The residence time of the solution in the anode chamber for the anode is The residence time of the solution in the cathode chamber for the cathode is ; The current density of the power supply assembly (5) is .

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