A copper plating wastewater treatment system and treatment method

Abstract

The application discloses a copper plating wastewater treatment system, which comprises a thermal regeneration cell stack, a gas-liquid separator, an electric coagulation device and a biological degradation device. 2+ The gas-liquid separation is carried out to obtain NH3 and Cu 2+ The low-concentration Cu-containing wastewater obtained through the thermal regeneration cell stack is further treated by the electric coagulation device to reduce the Cu content in the wastewater 2+ The biological degradation device is used for biodegrading the Cu-containing wastewater obtained through the electric coagulation device; and the application further discloses a treatment method for treating copper plating wastewater by using the copper plating wastewater treatment system. Compared with the prior art, the system can realize copper ion recovery and reactant regeneration, save production raw materials, utilize low-grade heat energy, save reagents and equipment required by the complex breaking reaction, save resources and reduce thermal pollution.

Description

Technical Field

[0001] This invention relates to the field of wastewater recycling and treatment technology, and specifically discloses a copper plating wastewater treatment system and treatment method. Background Technology

[0002] Traditional alkaline precipitation methods cost as much as 52.9 yuan and 29.5 yuan per ton of nickel and copper wastewater, respectively, and the heavy metal resources cannot be recovered. Electroplating wastewater treatment projects built around "adsorption-electrodeposition technology" can achieve a recovery rate of over 90% for heavy metals copper and nickel in the wastewater. When the initial nickel concentration in the nickel-containing raw water is 600 mg / L and the copper concentration in the copper-containing raw water is 1000 mg / L, the direct costs of adsorption and electrodeposition per cubic meter of raw water are 23.5 yuan and 23.6 yuan, respectively. The current market prices for high-purity copper and nickel plates are 50,000 yuan / ton and 100,000 yuan / ton, respectively. Based on this, a resource recovery device for nickel and copper wastewater with a treatment capacity of 100 tons / day can generate a net daily profit of 2,510 yuan and 1,920 yuan for copper and nickel, respectively. On the one hand, excessive discharge of copper ions into the environment can have a significant impact on the ecological environment and human health; on the other hand, existing copper-containing wastewater treatment systems mostly suffer from high energy consumption and high equipment costs. According to environmental protection department requirements (GB21900-2008), the discharge limit for copper ions in electroplating wastewater from existing enterprises is 1.0 mg / L, and the limit for newly built enterprises is 0.5 mg / L. To implement relevant national policies and promote the sustainable development of enterprises, it is essential to optimize and upgrade the existing wastewater treatment processes of electroplating enterprises. Summary of the Invention

[0003] The purpose of this invention is to provide a copper plating wastewater treatment system. This system can realize copper ion recovery and reactant regeneration, saving production raw materials. The system can utilize low-grade heat energy, saving reagents and equipment required for complexation breaking reactions, saving resources, and reducing thermal pollution.

[0004] The objective of this invention is achieved through the following technical solution: a copper plating wastewater treatment system, comprising:

[0005] A thermal regeneration battery stack is used to convert high-concentration Cu-containing electroplating wastewater from an electroplating plant into low-concentration Cu-containing wastewater. The first anode inlet and the first cathode inlet of the thermal regeneration battery stack are both connected to the Cu-containing wastewater output end of the electroplating plant.

[0006] A gas-liquid separator is used to separate the anode product Cu(NH3)4 generated by the thermally regenerated battery stack. 2+ Gas-liquid separation yields NH3 and Cu 2+The inlet of the gas-liquid separator is connected to the anode outlet of the thermal regeneration battery stack, the gas outlet of the gas-liquid separator is connected to the second anode inlet of the thermal regeneration battery stack, and the liquid outlet of the gas-liquid separator is connected to the inlet of the electroplating plant.

[0007] The electrocoagulation device further reduces the Cu content in the low-concentration Cu-containing wastewater obtained from the thermal regeneration battery stack using electrocoagulation. 2+ The liquid content is such that the liquid inlet of the electrocoagulation device is connected to the liquid outlet of the cathode of the thermal regeneration battery stack;

[0008] A biodegradation device is used to biodegrade Cu-containing wastewater obtained from an electrocoagulation device, wherein the inlet of the biodegradation device is connected to the outlet of the electrocoagulation device.

[0009] The copper plating wastewater treatment system of this invention first uses a thermal regeneration battery stack for primary treatment. The low-concentration copper plating wastewater drawn from the cathode is then introduced into an electrocoagulation device for secondary treatment, and a biodegradation rotor for tertiary treatment. The thermal regeneration battery stack uses ammonia gas distributed by a gas-liquid separator to combine with copper ions transmitted from the electroplating plant at the anode to form tetraammonium and copper ions. The wastewater containing tetraammonium and copper ions drawn from the anode is pyrolyzed using the low-grade heat energy of the gas-liquid separator. The resulting high-concentration copper ions are returned to the electroplating plant for recycling, and the decomposed ammonia gas is returned to the anode for reuse. The electrical energy generated by the thermal regeneration battery stack is used to supplement the electrocoagulation device.

[0010] Preferably, a heat exchange device is also included to provide heat for the gas-liquid separator to separate Cu(NH3)4. 2+ The required heat is supplied through a heat exchanger. The inlet of the heat exchanger is connected to the steam condensate outlet of the electroplating plant, and the heat outlet of the heat exchanger is connected to the heat inlet of the gas-liquid separator. By employing the heat exchanger, low-grade waste heat is removed from the steam condensate after passing through it. This low-grade waste heat then enters the gas-liquid separator to separate the anode product Cu(NH3)4 generated from the thermal regeneration battery stack. 2+ The resulting steam condensate is then treated before being discharged.

[0011] Preferably, the heat exchange device is a plate heat exchanger. Plate heat exchangers have a high heat transfer coefficient, small flow channels, and corrugated plates with complex cross-sectional changes, which causes the flow direction and velocity of the fluid to change continuously, increasing the turbulence of the fluid, and thus achieving turbulence at very low flow rates.

[0012] Preferably, the anode and cathode of the thermally regenerated battery stack are made of the same material, both being composite electrodes. The composite electrode includes an internal frame and a surface coating layer. The internal frame is made of nickel foam, and the surface coating layer is made of copper. During the discharge process of the thermally regenerated battery stack, there are problems such as severe corrosion of the upper part of the copper foam electrode, leading to increased internal contact resistance and decreased battery performance. Therefore, the inventors used a nickel foam electrode as the frame and copper plating on the surface of the nickel electrode to enhance the discharge stability of the battery. This not only has little impact on the normal discharge performance of the thermally regenerated battery stack but also better solves the problem of insufficient continuous discharge caused by excessive corrosion of the upper part due to uneven NH3 distribution.

[0013] Preferably, the applied electric field of the thermally regenerated battery stack is -50V / m. Through experiments, including EIS analysis, batch discharge testing, and power curve testing, the inventors found that the performance improvement was most significant when the applied electric field was -50V / m. At this setting, the battery output power was 21% higher than the maximum output power of the reference group without an applied electric field, and the energy production was increased by 59%.

[0014] Preferably, the electrocoagulation device includes an electrolytic cell, the anode of which is a graphite plate, the cathode of which is a copper plate, and the electrode spacing is 28 mm. The anode inlet of the electrolytic cell is connected to the cathode outlet of the regenerated battery stack. Electrocoagulation is a method of depositing metallic substances by applying an electric current. In this invention, the anode of the electrocoagulation method uses a graphite plate, the cathode uses a copper plate, and an electric current is passed through, thereby further improving the removal rate of copper ions in copper-containing wastewater.

[0015] Preferably, the biodegradation device includes a biodegradation tank containing a biodegrading agent, and the inlet of the biodegradation tank is connected to the outlet of the electrocoagulation device. Several methods using biopolymers have successfully removed dyes and heavy metal ions. This invention employs a biodegradation device to further remove copper from copper-containing wastewater, ensuring that the treated wastewater meets discharge standards.

[0016] Preferably, the biodegrading agent is deacetylated chitosan. Deacetylated chitosan has a higher chelating capacity than all other polysaccharides due to its high primary amino content, and it also exhibits excellent biodegradability and low toxicity, making it suitable for wastewater treatment.

[0017] Another object of the present invention is to provide a method for treating copper plating wastewater using a copper plating wastewater treatment system, the method specifically including the following steps:

[0018] S1. High-concentration copper-containing wastewater from the electroplating plant is fed into a thermal regenerated battery stack. The reactions that occur at the anode and cathode of the thermal regenerated ammonia battery are as follows:

[0019] Anode reaction: Cu(s) + 4NH3(aq) → Cu(NH3)4 2+ (aq) + 2e-, E0 = -0.040V

[0020] Cathode reaction: Cu 2+ (aq)+2e-→Cu(s), E0=+0.340V

[0021] Cu(NH3)4 obtained at the anode 2+ The low-concentration Cu-containing electroplating wastewater obtained from the cathode is fed into the gas-liquid separator and then into the electrocoagulation device, where the generated electrical energy is also fed into the electrocoagulation device.

[0022] S2, the gas-liquid separator removes the anode product Cu(NH3)4 2+ Gas-liquid separation yields NH3 and Cu 2+ The Cu obtained therefrom 2 + The NH3 is returned to the electroplating plant for electroplating, and the resulting NH3 is passed into the anode of the thermal regeneration battery stack.

[0023] S3. The electrical energy generated by the thermal regeneration battery stack is used in the electrocoagulation device to further reduce the Cu content in the low-concentration Cu-containing electroplating wastewater by electrocoagulation. Then, the wastewater is introduced into the biodegradation tank for final treatment to obtain water resources that meet the discharge conditions.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. This system can recycle and utilize low-grade waste heat, enabling the internal material recycling and regeneration of the system, saving resources, reducing thermal pollution, and having heat exchange equipment in multiple places throughout the process. Through multi-stage coupling, heat loss is fully reduced, and the overall thermal efficiency of the process is improved.

[0026] 2. This invention places the thermal regeneration battery, which simultaneously treats wastewater and generates electricity, in the first stage of the gradient treatment process. This is suitable for treating high-concentration copper-containing wastewater and ensuring energy replenishment for subsequent electrocoagulation. While electrocoagulation is used for secondary treatment of copper-containing wastewater, its efficiency is low when the copper ion concentration is low. Therefore, once the concentration of copper-containing wastewater treated by electrocoagulation reaches a certain limit, biological methods are the most effective final treatment method.

[0027] 3. The system of this invention can realize copper ion recovery and reactant regeneration, saving production raw materials; the system can utilize low-grade heat energy, saving reagents and equipment required for complex breaking reaction, saving resources and reducing thermal pollution; the core components of the system are strengthened to improve the copper ion recycling rate and waste heat utilization rate; the power generated by the battery inside the system can supplement the power consumption of electrocoagulation method, reducing the system's energy consumption. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the copper plating wastewater treatment system of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the thermal regenerable battery stack of the present invention;

[0030] Figure 3 These are the maximum output power curves of the batteries under different applied electric fields in Examples 1-5 of the present invention;

[0031] Figure 4 These are the EIS battery resistance analysis diagrams for Examples 1-5 of the present invention under different applied electric fields;

[0032] Figure 5 The figures show the performance curves and polarization curves of Embodiments 1 and 6 of the present invention.

[0033] Figure 6 The diagram shows the anode and cathode cyclic discharge curves of Embodiments 1 and 6 of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] It should be noted that similar symbols and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "inner," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The accompanying drawings of the embodiments of this invention provide a coordinate system XYZ, where the positive direction of the X-axis represents the front, the negative direction of the X-axis represents the rear, the positive direction of the Y-axis represents the right, the negative direction of the Y-axis represents the left, the positive direction of the Z-axis represents the upper, and the negative direction of the Z-axis represents the lower.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0039] Combination Figures 1-2 This invention provides a copper plating wastewater treatment system, comprising:

[0040] The thermal regeneration battery stack is used to convert high-concentration Cu-containing electroplating wastewater from the electroplating plant into low-concentration Cu-containing wastewater. The first anode inlet and the first cathode inlet of the thermal regeneration battery stack are both connected to the Cu-containing wastewater output end of the electroplating plant.

[0041] A gas-liquid separator is used to separate the anode product Cu(NH3)4 generated from the thermal regeneration battery stack. 2+ Gas-liquid separation yields NH3 and Cu 2+ The inlet of the gas-liquid separator is connected to the anode outlet of the thermal regeneration battery stack, the gas outlet of the gas-liquid separator is connected to the second anode inlet of the thermal regeneration battery stack, and the liquid outlet of the gas-liquid separator is connected to the inlet of the electroplating plant.

[0042] The electrocoagulation device further reduces the Cu content in the low-concentration Cu-containing wastewater obtained from the thermal regeneration battery stack using electrocoagulation. 2+ The liquid content is such that the inlet of the electrocoagulation device is connected to the cathode outlet of the thermal regeneration battery stack.

[0043] The biodegradation device is used to biodegrade Cu-containing wastewater obtained from the electrocoagulation device. The inlet of the biodegradation device is connected to the outlet of the electrocoagulation device.

[0044] The copper plating wastewater treatment system of this invention first uses a thermal regeneration battery stack for primary treatment. The low-concentration copper plating wastewater drawn from the cathode is then introduced into an electrocoagulation device for secondary treatment, and a biodegradation rotor for tertiary treatment. The thermal regeneration battery stack uses ammonia gas distributed by a gas-liquid separator to combine with copper ions transmitted from the electroplating plant at the anode to form tetraammonium and copper ions. The wastewater containing tetraammonium and copper ions drawn from the anode is pyrolyzed using the low-grade heat energy of the gas-liquid separator. The resulting high-concentration copper ions are returned to the electroplating plant for recycling, and the decomposed ammonia gas is returned to the anode for reuse. The electrical energy generated by the thermal regeneration battery stack is used to supplement the electrocoagulation device.

[0045] In a specific embodiment, a heat exchange device may also be included to provide a gas-liquid separator for separating Cu(NH3)4. 2+ The required heat is supplied through a heat exchanger. The inlet of the heat exchanger is connected to the steam condensate outlet of the electroplating plant, and the heat outlet of the heat exchanger is connected to the heat inlet of the gas-liquid separator. By using the heat exchanger, low-grade waste heat is removed from the steam condensate after passing through it. This low-grade waste heat then enters the gas-liquid separator to separate the anode product Cu(NH3)4 generated from the thermal regeneration battery stack. 2+ The resulting steam condensate is then treated before being discharged.

[0046] In a specific implementation, the heat exchange device is a plate heat exchanger. Plate heat exchangers have a high heat transfer coefficient, small flow channels, and corrugated plates with complex cross-sectional changes, which causes the flow direction and velocity of the fluid to change continuously, increasing the turbulence of the fluid, thus achieving turbulence at very low flow rates.

[0047] In a specific embodiment, the anode and cathode of the thermally regenerated battery stack are made of the same material, both being composite electrodes. The composite electrode includes an internal frame and a surface coating layer. The internal frame is made of nickel foam, and the surface coating layer is made of copper. During the discharge process of the thermally regenerated battery stack, there are problems such as severe corrosion of the upper part of the copper foam electrode, leading to increased internal contact resistance and decreased battery performance. Therefore, the inventors used a nickel foam electrode as the frame and copper plating on the surface of the nickel electrode to enhance the discharge stability of the battery. This not only has little impact on the normal discharge performance of the thermally regenerated battery stack but also better solves the problem of insufficient continuous discharge caused by excessive corrosion of the upper part due to uneven NH3 distribution.

[0048] In a specific implementation, the applied electric field of the thermally regenerated battery stack is -50V / m. Through experiments, including EIS analysis, batch discharge testing, and power curve testing, the inventors determined that the performance improvement was most significant when the applied electric field was -50V / m. At this setting, the battery output power was 21% higher than the maximum output power of the reference group without an applied electric field, and the energy production was increased by 59%.

[0049] In a specific embodiment, the electrocoagulation device includes an electrolytic cell, with a graphite electrode plate as the anode and a copper plate as the cathode, and an electrode spacing of 28 mm. The anode inlet of the electrolytic cell is connected to the cathode outlet of the regenerated battery stack. Electrocoagulation is a method of depositing metallic substances by applying an electric current. In this invention, the anode of the electrocoagulation method uses a graphite electrode plate, the cathode uses a copper plate, and an electric current is passed through, thereby further improving the removal rate of copper ions in copper-containing wastewater.

[0050] In a specific embodiment, the biodegradation device includes a biodegradation tank containing a biodegrading agent. The inlet of the biodegradation tank is connected to the outlet of the electrocoagulation device. Several methods using biopolymers have successfully removed dyes and heavy metal ions. This invention employs a biodegradation device to further remove copper from copper-containing wastewater, ensuring that the treated wastewater meets discharge standards.

[0051] In a specific embodiment, the biodegrading agent is deacetylated chitosan. Deacetylated chitosan has a higher chelating capacity than all other polysaccharides due to its high primary amino content, and it also exhibits excellent biodegradability and low toxicity, making it suitable for wastewater treatment.

[0052] Another objective of this invention is to provide a method for treating copper plating wastewater using a copper plating wastewater treatment system, the method specifically including the following steps:

[0053] S1. High-concentration copper-containing wastewater from the electroplating plant is fed into a thermal regenerated battery stack. The reactions that occur at the anode and cathode of the thermal regenerated ammonia battery are as follows:

[0054] Anode reaction: Cu(s) + 4NH3(aq) → Cu(NH3)4 2+ (aq) + 2e-, E0 = -0.040V

[0055] Cathode reaction: Cu 2+ (aq)+2e-→Cu(s), E0=+0.340V

[0056] Cu(NH3)4 obtained at the anode 2+ The low-concentration Cu-containing electroplating wastewater obtained from the cathode is fed into the gas-liquid separator and then into the electrocoagulation device, where the generated electrical energy is also fed into the electrocoagulation device.

[0057] S2, the gas-liquid separator removes the anode product Cu(NH3)4 2+ Gas-liquid separation yields NH3 and Cu 2+ The Cu obtained therefrom 2 + The NH3 is returned to the electroplating plant for electroplating, and the resulting NH3 is passed into the anode of the thermal regeneration battery stack.

[0058] S3. The electrical energy generated by the thermal regeneration battery stack is used in the electrocoagulation device to further reduce the Cu content in the low-concentration Cu-containing electroplating wastewater by electrocoagulation. Then, the wastewater is introduced into the biodegradation tank for final treatment to obtain water resources that meet the discharge conditions.

[0059] Example 1

[0060] This embodiment provides a copper plating wastewater treatment system, including: a thermal regeneration battery stack, used to convert high-concentration Cu-containing electroplating wastewater output from the electroplating plant into low-concentration Cu-containing wastewater. The first anode inlet and the first cathode inlet of the thermal regeneration battery stack are both connected to the Cu-containing wastewater output end of the electroplating plant. The anode and cathode of the thermal regeneration battery stack are made of the same material, which are both composite electrodes. The composite electrode includes an internal frame and a surface coating layer. The material of the internal frame is nickel foam, and the material of the surface coating layer is copper. The applied electric field of the thermal regeneration battery stack is -50V / m.

[0061] A gas-liquid separator is used to separate the anode product Cu(NH3)4 generated from the thermal regeneration battery stack. 2+ Gas-liquid separation yields NH3 and Cu 2+ The inlet of the gas-liquid separator is connected to the anode outlet of the thermal regeneration battery stack, the gas outlet of the gas-liquid separator is connected to the second anode inlet of the thermal regeneration battery stack, and the liquid outlet of the gas-liquid separator is connected to the inlet of the electroplating plant.

[0062] The electrocoagulation device further reduces the Cu content in the low-concentration Cu-containing wastewater obtained from the thermal regeneration battery stack using electrocoagulation. 2+ The electrocoagulation device includes an electrolytic cell, the anode of which is a graphite plate and the cathode of which is a copper plate, with an electrode spacing of 28 mm. The anode inlet of the electrolytic cell is connected to the cathode outlet of the regenerated battery stack.

[0063] A biodegradation device is used to biodegrade Cu-containing wastewater obtained from an electrocoagulation device. The biodegradation device includes a biodegradation tank containing a biodegrading agent. The inlet of the biodegradation tank is connected to the outlet of the electrocoagulation device. The biodegrading agent is deacetylated chitosan.

[0064] Plate heat exchangers are used to provide gas-liquid separators for separating Cu(NH3)4. 2+ The required heat is supplied by connecting the liquid inlet of the plate heat exchanger to the steam condensate outlet of the electroplating plant, and the heat outlet of the plate heat exchanger to the heat inlet of the gas-liquid separator.

[0065] The method for treating copper plating wastewater using the copper plating wastewater treatment system of this embodiment specifically includes the following steps:

[0066] S1. High-concentration copper-containing wastewater from the electroplating plant is fed into a thermal regenerated battery stack. The reactions that occur at the anode and cathode of the thermal regenerated ammonia battery are as follows:

[0067] Anode reaction: Cu(s) + 4NH3(aq) → Cu(NH3)4 2+ (aq) + 2e-, E0 = -0.040V

[0068] Cathode reaction: Cu 2+ (aq)+2e-→Cu(s), E0=+0.340V

[0069] Cu(NH3)4 obtained at the anode 2+ The low-concentration Cu-containing electroplating wastewater obtained from the cathode is fed into the gas-liquid separator and then into the electrocoagulation device, where the generated electrical energy is also fed into the electrocoagulation device.

[0070] S2. After passing through a heat exchanger, the low-grade waste heat in the steam condensate from the electroplating plant is removed. This low-grade waste heat then enters a gas-liquid separator to separate the anode product Cu(NH3)4 generated from the thermal regeneration battery stack. 2+ The resulting steam condensate is then treated before being discharged.

[0071] S3, the gas-liquid separator separates the anode product Cu(NH3)4 2+ Gas-liquid separation yields NH3 and Cu 2+ The Cu obtained therefrom 2 + The NH3 is returned to the electroplating plant for electroplating, and the resulting NH3 is passed into the anode of the thermal regeneration battery stack.

[0072] S4. The electricity generated by the thermal regeneration battery stack is used in the electrocoagulation device to further reduce the Cu content in the low-concentration Cu-containing electroplating wastewater by electrocoagulation. Then, the wastewater is introduced into the biodegradation tank for final treatment to obtain water resources that meet the discharge conditions.

[0073] Example 2

[0074] The only difference from Example 1 is that the external electric field of the thermal regenerable battery stack in this example is 0V / m. Everything else is the same as in Example 1, and will not be repeated here.

[0075] Example 3

[0076] The only difference from Example 1 is that the external electric field of the thermal regenerable battery stack in this example is 50V / m. Everything else is the same as in Example 1, and will not be repeated here.

[0077] Example 4

[0078] The only difference from Example 1 is that the external electric field of the thermal regenerable battery stack in this example is 100V / m. Everything else is the same as in Example 1, and will not be repeated here.

[0079] Example 5

[0080] The only difference from Example 1 is that the external electric field of the thermal regenerable battery stack in this example is -100V / m. Everything else is the same as in Example 1, and will not be repeated here.

[0081] Example 6

[0082] The only difference from Example 1 is that the cathode and anode electrode materials of the thermal regenerable battery stack in this example are both foamed copper. Everything else is the same as in Example 1, and will not be repeated here.

[0083] The performance of the copper plating wastewater treatment systems of Examples 1-5 of this invention was tested, and the test results are as follows: Figure 3 and Figure 4 As shown, where Figure 3 To determine the maximum output power of the thermal regenerable battery stack under different applied electric fields, from Figure 3 It can be seen that when the applied electric field is -50V / m, the power output of the battery is 21% higher than the maximum output power of the reference group without an applied electric field, and the power generation is increased by 59%. Figure 4 The EIS battery resistance analysis graphs are shown under different applied electric fields. The EIS analysis reveals that a positive applied electric field increases the internal resistance of the reaction, while a negative applied electric field decreases it. Considering both diffusion resistance and reaction resistance, the ohmic internal resistance is still lowest when the applied electric field is -50V / m. Figure 4 As shown in the batch discharge experiment, the output voltage decreases gradually in the initial period, but drops sharply after a certain time. Performance tests were conducted on the copper plating wastewater treatment systems of Examples 1 and 6, and the results are as follows. Figure 5 and Figure 6 As shown, where Figure 5 Performance curves and polarization curves of Cu / Ni composite electrode and copper foam electrode are shown. Figure 6 The figures show the cyclic discharge curves of the Cu / Ni composite electrode and the foamed copper electrode, where red represents the Cu / Ni composite electrode and blue represents the foamed copper electrode. Figure 5 and Figure 6 It can be seen that using Cu / Ni composite does not have a significant impact on the normal discharge performance of TRAB, but it can better solve the problem of unsustainable discharge caused by excessive corrosion of the upper part due to uneven distribution of NH3.

[0084] The inventors used the copper plating wastewater treatment system of Example 1 to treat the wastewater, reducing the copper ion concentration from an initial 156.25 mol / m³. 3After being treated by this copper plating wastewater treatment system, the concentration becomes 0.00734 mol / m³. 3 The concentration is 0.47 mg / L, which is lower than the 1 mg / L emission limit for existing electroplating plants in the national standard, and also lower than the 0.5 mg / L emission concentration limit for copper-containing wastewater from newly built electroplating plants in the national standard. Furthermore, calculations show that the thermal regeneration battery stack in the copper plating wastewater treatment system of this invention generates 4820.05 J of energy, while the electrocoagulation method consumes 17550 J of energy, with the energy generated making up for 27.5% of the energy consumption.

[0085] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the scope of protection of this invention.

Claims

1. A copper plating wastewater treatment system, characterized in that, include: A thermal regeneration battery stack is used to convert high-concentration Cu-containing electroplating wastewater from an electroplating plant into low-concentration Cu-containing wastewater. The first anode inlet and the first cathode inlet of the thermal regeneration battery stack are both connected to the Cu-containing wastewater output end of the electroplating plant. A gas-liquid separator is used to separate the anode product Cu(NH3)4 generated by the thermally regenerated battery stack. 2+ Gas-liquid separation yields NH3 and Cu 2+ The inlet of the gas-liquid separator is connected to the anode outlet of the thermal regeneration battery stack, the gas outlet of the gas-liquid separator is connected to the second anode inlet of the thermal regeneration battery stack, and the liquid outlet of the gas-liquid separator is connected to the inlet of the electroplating plant. The electrocoagulation device further reduces the Cu content in the low-concentration Cu-containing wastewater obtained from the thermal regeneration battery stack using electrocoagulation. 2+ The liquid content is such that the liquid inlet of the electrocoagulation device is connected to the liquid outlet of the cathode of the thermal regeneration battery stack; A biodegradation device is used to biodegrade Cu-containing wastewater obtained from an electrocoagulation device, wherein the inlet of the biodegradation device is connected to the outlet of the electrocoagulation device. The anode and cathode of the thermal regenerable battery stack are made of the same material, both being composite electrodes. The composite electrode includes an internal frame and a surface coating layer. The material of the internal frame is nickel foam, and the material of the surface coating layer is copper. The applied electric field of the thermal regenerative battery stack is -50V / m; The biodegradation device includes a biodegradation tank containing a biodegrading agent, and the inlet of the biodegradation tank is connected to the outlet of the electrocoagulation device. The biodegradable agent is deacetylated chitosan.

2. The copper plating wastewater treatment system as described in claim 1, characterized in that, It also includes a heat exchange device for providing heat to the gas-liquid separator for separating Cu(NH3)4. 2+ The required heat is provided by connecting the liquid inlet of the heat exchange device to the steam condensate outlet of the electroplating plant, and connecting the heat outlet of the heat exchange device to the heat inlet of the gas-liquid separator.

3. The copper plating wastewater treatment system as described in claim 2, characterized in that, The heat exchange device is a plate heat exchanger.

4. The copper plating wastewater treatment system as described in claim 1, characterized in that, The electrocoagulation device includes an electrolytic cell, the anode of which is a graphite plate and the cathode of which is a copper plate, with an electrode spacing of 28 mm. The anode inlet of the electrolytic cell is connected to the cathode outlet of the regenerated battery stack.

5. A method for treating copper plating wastewater using the copper plating wastewater treatment system according to any one of claims 1-4, characterized in that, The processing method specifically includes the following steps: S1. High-concentration copper-containing wastewater from the electroplating plant is fed into a thermal regenerated battery stack. The reactions that occur at the anode and cathode of the thermal regenerated ammonia battery are as follows: Anode reaction: Cu(s) + 4NH3(aq) → Cu(NH3)4 2+ (aq) + 2e-, E0 = -0.040V Cathode reaction: Cu 2+ (aq) + 2e- → Cu(s), E0 = +0.340V Cu(NH3)4 obtained at the anode 2+ The low-concentration Cu-containing electroplating wastewater obtained from the cathode is fed into the gas-liquid separator and then into the electrocoagulation device, where the generated electrical energy is also fed into the electrocoagulation device. S2, the gas-liquid separator separates the anode product Cu(NH3)4 2+ Gas-liquid separation yields NH3 and Cu 2+ The Cu obtained therefrom 2+ The NH3 is returned to the electroplating plant for electroplating, and the resulting NH3 is passed into the anode of the thermal regeneration battery stack. S3. The electrical energy generated by the thermal regeneration battery stack is used in the electrocoagulation device to further reduce the Cu content in the low-concentration Cu-containing electroplating wastewater by electrocoagulation. Then, the wastewater is introduced into the biodegradation tank for final treatment to obtain water resources that meet the discharge conditions.

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