Method for regenerating acidic etching waste liquid and recovering copper

Abstract

The invention relates to the technical field of tires, in particular to an acidic etching waste liquid regeneration and copper recovery method and a preparation method thereof, and the acidic etching waste liquid is prepared from the following raw materials in parts by mass: 40-70 parts of a composite rubber composition, 5-25 parts of a plasticizer, 10-15 parts of an auxiliary agent, 2-5 parts of a vulcanizing agent, 0.5-1.5 parts of a vulcanization accelerator and 1-4 parts of stearic acid. The tire rubber disclosed by the invention has relatively good wear resistance, mechanical property, anti-aging property and self-repairing capability.

Description

Technical Field

[0001] This invention relates to the field of etching solution treatment technology, and in particular to a method for regenerating acidic etching waste liquid and recovering copper. Background Technology

[0002] In the printed circuit board (PCB) manufacturing industry, etching is a crucial step in forming circuit patterns. Acid etching, with its advantages of high etching rate, minimal side etching, and high precision, has become the mainstream technology for etching outer layer circuits. However, this process generates large quantities of acidic etching wastewater with copper content as high as 120-170 g / L. This wastewater contains substances such as copper chloride, cuprous chloride, hydrochloric acid, and oxidants. This type of wastewater is listed in the "National Hazardous Waste List." Direct discharge without effective treatment not only wastes copper resources but also causes serious pollution to water bodies, soil, and ecosystems. Currently, the global PCB industry generates over ten million tons of acidic etching wastewater annually. Achieving resource utilization and pollution control has become a core issue for the industry's sustainable development.

[0003] For the treatment of acidic etching wastewater, the industry has developed diversified technological approaches. The sponge copper method generates sponge copper through an iron powder displacement reaction, but suffers from high acid consumption and the need for secondary treatment of the filtrate. While extraction can separate copper ions, it faces challenges such as high extractant consumption and severe equipment corrosion. Neutralization converts copper into copper hydroxide precipitate, but the product has low added value and generates large amounts of saline wastewater. Evaporation crystallization is too energy-intensive and difficult to scale up. In contrast, electrolysis, with its advantages of high copper recovery rate, recyclable regenerated liquid, and closed-loop process, has become the mainstream technology. Its core principle is to achieve the directional migration and speciation of copper ions through electrochemical reactions, depositing high-purity metallic copper at the cathode while simultaneously oxidizing monovalent copper to divalent copper ions with etching activity at the anode, thus restoring the etching capacity of the wastewater.

[0004] The electrolysis technology system incorporates three key innovations. In terms of electrolytic cell design, a composite diaphragm structure divides the electrolytic cell into a cathode chamber and an anode chamber. The cation exchange membrane selectively allows copper ions to pass through while blocking chloride ion migration, effectively suppressing side reactions. For example, patent CN111394729B discloses an "electrolysis device and its printed circuit board acid etching waste liquid regeneration and copper recovery equipment," including a press and an electrolysis unit. The press has a holding space within which the electrolysis unit is installed. The electrolysis unit includes an anode plate, an anode frame, an ion exchange layer, a cathode frame, and a cathode plate. The press sequentially compresses the anode plate, anode frame, ion exchange layer, cathode frame, and cathode plate to form a sealed anode and cathode chamber. This invention's electrolysis device uses a press to sequentially compress the anode plate, anode frame, ion exchange layer, cathode frame, and cathode plate of the electrolysis unit to form a sealed anode and cathode chamber, preventing the release of gases generated during the electrolysis reaction, avoiding corrosive gases from damaging the equipment, and improving the quality of the working environment. For example, CN114855171B discloses "an acidic etching solution waste liquid treatment system and method," which electrolyzes the etching solution waste liquid to form copper and chlorine gas, recovers the formed copper, then passes the chlorine gas back into the electrolyte after electrolysis to dissolve it, and finally adds a reagent to the electrolyte to form the original etching solution. By electrolyzing the etching solution waste liquid, copper in the waste liquid is recovered without introducing new impurities. The chlorine gas generated during electrolysis is passed into the recycled electrolyte, and the chlorine gas reacts with the waste liquid, allowing the chlorine gas to be reused before treatment, increasing the chloride ion concentration of the etching solution waste liquid, reducing the amount of chemical reagents added later, and reducing the cost of subsequent chlorine gas treatment, thereby achieving the recycling of etching solution waste liquid.

[0005] Current innovations in the electrolytic recovery of acidic etching waste mainly focus on improvements to the electrolytic cell. However, as a core component of the electrolytic process, the performance of the cation exchange membrane is crucial for copper ion recovery and the regeneration of acidic etching waste. Therefore, developing a stable and efficient method for regenerating acidic etching waste and recovering copper, capable of producing regenerated acidic etching solution that meets the specifications of the semiconductor industry, is urgently needed. Summary of the Invention

[0006] The purpose of this invention is to provide a method for regenerating acidic etching waste liquid and recovering copper, in order to solve the problems in the current electrolytic process for recovering acidic etching waste liquid, such as poor mechanical properties of cation exchange membranes, damage after long-term use leading to poor recovery process effect, and the inability of the regenerated etching liquid to meet high standards.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides a method for regenerating acidic etching waste liquid and recovering copper, comprising the following steps: mixing a first acidic etching waste liquid with ascorbic acid as an anolyte, mixing a second acidic etching waste liquid with deionized water as a catholyte, adding the mixture to an electrolytic cell for electrolytic treatment, mixing the anolyte and catholyte to obtain a regenerated acidic etching liquid, and stripping the solid from the cathode to obtain metallic copper. The anode chamber and cathode chamber of the electrolytic cell are separated by a cation exchange membrane; The cation exchange membrane is prepared from a compound represented by Formula I. (I); Where z = x + y, and x, y, and z are integers.

[0008] Perfluorosulfonic acid (PFSA) membranes have also demonstrated excellent performance in many other fields, such as seawater desalination, chemical catalysis, various electrolytic preparation devices, wastewater treatment, hydrogen production through water electrolysis, ozone production, and gas separation. Currently, PFSA membranes are often used as cation exchange membranes to separate the anode and cathode areas in electrolytic cells for the electrolytic regeneration of acidic etching waste liquid. However, research has found that the size of PFSA membranes changes due to water absorption in aqueous environments, resulting in a corresponding decrease in mechanical strength. This affects the efficiency of the electrolytic regeneration of acidic etching waste liquid. Damage during application is difficult to detect, leading to the need to restart the regeneration process and delaying the process cycle.

[0009] This application uses a mixture of a first acidic etching waste liquid and ascorbic acid as the anolyte, and a mixture of a second acidic etching waste liquid and deionized water as the catholyte. These are then separated by a self-made cation exchange membrane with a specific structure. The cation exchange membrane contains fluorine, which imparts strong resistance to strong acids, strong alkalis, and oxidizing media, resulting in a stable membrane structure and extended service life. Furthermore, the side chain ends contain hydrophilic sulfonic acid groups and carboxyl groups, which synergistically enhance the effect of blocking anions while allowing selective permeation of cations, preventing cross-contamination. This allows the resulting regenerated etching waste liquid to be used in more sophisticated chip and semiconductor industries.

[0010] In some embodiments, the mass ratio of the first acidic etching waste liquid to ascorbic acid is 1:(0.00001~0.0001).

[0011] Preferably, the mass ratio of the first acidic etching waste liquid to ascorbic acid is 1:0.000055.

[0012] This application demonstrates that by adding ascorbic acid to acidic etching waste liquid, side reactions can be suppressed, metal ion reduction can be promoted, and the stability of the etching solution can be improved.

[0013] In some embodiments, the second acidic etching waste liquid is mixed with deionized water to make the copper ion concentration in the cathode liquid 30~35g / L.

[0014] Preferably, the second acidic etching waste liquid is mixed with deionized water to make the copper ion concentration in the cathode liquid 32g / L.

[0015] In some embodiments, the DC voltage of the electrolysis is 5~7V.

[0016] Preferably, the DC voltage for electrolysis is 6V.

[0017] In some embodiments, the current density of the electrolysis is 800~1000 A / dm³. 2 .

[0018] Preferably, the current density of the electrolysis is 900 A / dm³. 2 .

[0019] In some embodiments, the electrolysis temperature is 50~60°C.

[0020] Preferably, the electrolysis temperature is 55°C.

[0021] In some embodiments, the electrolysis time is 5 to 10 hours.

[0022] In some embodiments, the method for preparing the cation exchange membrane includes the following steps: S1. Under an inert protective gas atmosphere, 1,4-difluorobenzene, 4,4'-dihydroxybiphenyl, glycerol and potassium carbonate are mixed, N,N-dimethylformamide and toluene are added and stirred, the mixture is heated to 140~150℃ and stirred at a constant temperature for 24~28h, cooled to room temperature, added to deionized water, filtered, washed and dried to obtain product A; S2. Under an inert protective gas atmosphere, product A obtained in step S1 is mixed with N-methylpyrrolidone and added to N,N-dimethylformamide, followed by potassium carbonate, sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate and sodium p-chlorobenzoate. The mixture is heated to 140~150℃ and stirred for 3~4 hours. After cooling to room temperature, the mixture is dialyzed through a dialysis bag and dried to obtain product B. S3. The product B obtained in step S2 is mixed with methacrylic acid and acrylate and added to toluene. Then an initiator is added, the temperature is raised to 70~80℃ and stirred for 1~3h. Then centrifuge, filter, wash and dry to obtain the compound shown in Formula I. S4. Dissolve the compound of formula I obtained in step S3 in N-methylpyrrolidone, cast it into a film in a flat glass tank, dry it, remove it and soak it in dilute hydrochloric acid solution for 20-24 hours, wash it with deionized water to obtain a cation exchange membrane.

[0023] The cation exchange membrane of this application first uses 1,4-difluorobenzene, 4,4'-dihydroxybiphenyl, and glycerol as main raw materials to obtain product A with a polymer structure. Then, by utilizing the active hydroxyl groups on product A to react with sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate, product B with side chains containing fluorine, sulfonic acid groups, and carboxyl groups is obtained. Finally, product B is mixed with methacrylic acid and acrylate, and the methacrylic acid and acrylate are wrapped around the molecular chain of product B through a polymerization reaction, which enhances the mechanical properties of the cation exchange membrane and improves its service life. At the same time, the sulfonic acid groups and carboxyl groups can produce a synergistic effect, improving the selective permeability of the cation exchange membrane.

[0024] In some embodiments, in step S1, the molar ratio of 1,4-difluorobenzene, 4,4'-dihydroxybiphenyl and glycerol is 1:(0.4~0.6):(0.4~0.6).

[0025] Preferably, in step S1, the molar ratio of 1,4-difluorobenzene, 4,4'-dihydroxybiphenyl and glycerol is 1:0.5:0.5.

[0026] In some embodiments, in step S1, the molar ratio of 1,4-difluorobenzene to potassium carbonate is 1:(1.2~1.5).

[0027] In some embodiments, in step S2, the molar ratio of product A to sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate is 1:(0.4~0.6).

[0028] Preferably, in step S2, the molar ratio of product A to sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate is 1:0.5.

[0029] In some embodiments, in step S2, the molar ratio of product A to sodium p-chlorobenzoate is 1:(0.4~0.6).

[0030] In some embodiments, in steps S2 and S3, the mass ratio of product B, methacrylic acid, and acrylate is 1:(0.1~0.3):(0.1~0.3).

[0031] Preferably, in step S2 and step S3, the mass ratio of product B, methacrylic acid, and acrylate is 1:0.2:0.2.

[0032] Compared with the prior art, the present invention has the following beneficial effects: (1) In this invention, a first acidic etching waste liquid is mixed with ascorbic acid as the anolyte, and a second acidic etching waste liquid is mixed with deionized water as the catholyte. Then, a self-made cation exchange membrane with a specific structure is used to separate them. The cation exchange membrane of this application contains fluorine, which can give the membrane a strong resistance to strong acids, strong alkalis and oxidizing media, and the membrane structure is stable and the service life is enhanced. In addition, the side chain ends contain hydrophilic sulfonic acid groups and carboxyl groups, which can work synergistically to block anions and allow selective permeation of cations, avoiding cross-contamination, so that the obtained regenerated etching waste liquid can be used in more precise chip and semiconductor industries.

[0033] (2) The cation exchange membrane of the present invention first uses 1,4-difluorobenzene, 4,4'-dihydroxybiphenyl and glycerol as the main raw materials to obtain product A with a polymer structure. Then, by using the active hydroxyl groups on product A to react with sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate, product B with side chains containing fluorine, sulfonic acid and carboxyl groups is obtained. Finally, product B is mixed with methacrylic acid and acrylate, and methacrylic acid and acrylate are wrapped in the molecular chain of product B through polymerization reaction, which enhances the mechanical properties of the cation exchange membrane and improves its service life. At the same time, the sulfonic acid and carboxyl groups can produce a synergistic effect and improve the selective permeability of the cation exchange membrane. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0035] Unless otherwise specified, the post-processing operations described below, such as "heating", "stirring", "filtration", "drying", "dialysis with dialysis bags", "centrifugation", "electrolysis", and "stripping", can be selected by those skilled in the art based on actual conditions, and are not further limited.

[0036] In the following examples and comparative examples, the perfluorosulfonic acid membrane was purchased from Beijing Shenqian Technology Co., Ltd.

[0037] The preparation of sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate includes the following steps: S21. Mix 5g of 4-chlorophenol and 87mL of a methanol solution of 0.9mol / L potassium hydroxide, then concentrate under reduced pressure at 80℃ and 26kPa to obtain a crude product. Then dry the crude product to obtain a white solid. S22. Under N2 atmosphere, 6g of the white solid obtained in step S21 was added to 15ml of dimethyl sulfoxide and dissolved. 15ml of 1,2-dibromotetrafluoroethane was added at 40℃. The mixture was heated to 60℃ and stirred at a constant temperature for 6h. After the reaction was completed, ice water was added to dilute to 60ml. The mixture was extracted, the organic phases were combined, and the mixture was concentrated under reduced pressure to obtain an oily product. S23. Under N2 atmosphere, mix 3g of the oily product obtained in step S22, 3.6g of sodium bicarbonate and 20ml of deionized water, then add 10ml of acetonitrile and 7.5g of sodium dithionite, heat to 65℃ and stir for 1h, then heat to 75℃ and stir for 3h. After the end, cool to room temperature and extract (ethyl acetate / deionized water), combine the organic phases, concentrate under reduced pressure to obtain a yellow solid; S24. Mix 3g of the yellow solid obtained in step S24 with 4ml of deionized water, cool to 0℃, add 1.5ml of 30wt% hydrogen peroxide solution, stir at a constant temperature for 4h, filter after completion, concentrate and dry the filtrate under reduced pressure to obtain sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate.

[0038] Preparation Example 1 The preparation method of the cation exchange membrane includes the following steps: S1. Under a N2 atmosphere, 0.1 mol of 1,4-difluorobenzene, 0.05 mol of 4,4'-dihydroxybiphenyl, 0.05 mol of glycerol and 0.13 mol of potassium carbonate were mixed, and 150 ml of N,N-dimethylformamide and 38 ml of toluene were added and stirred. The mixture was heated to 145 °C and stirred at a constant temperature for 26 h. After cooling to room temperature, the mixture was added to 300 ml of deionized water, filtered, washed, and dried to obtain product A. S2. Under a N2 atmosphere, 0.1 mol of product A obtained in step S1 was mixed with 600 ml of N-methylpyrrolidone and added to 300 ml of N,N-dimethylformamide. Then, 0.15 mol of potassium carbonate, 0.05 mol of sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate and 0.05 mol of sodium p-chlorobenzoate were added. The mixture was heated to 145 °C and stirred at a constant temperature for 3.5 h. After cooling to room temperature, the mixture was dialyzed through a dialysis bag and dried to obtain product B. S3. 20g of product B obtained in step S2 was mixed with 4g of methacrylic acid and 4g of acrylate and added to 200ml of toluene. Then 0.06g of benzoyl peroxide was added, and the mixture was heated to 75℃ and stirred for 2h. After centrifugation, filtration, washing, and drying, the compound represented by Formula I was obtained. (I); x=y=25, z=50; S4. Dissolve 10g of the compound shown in Formula I obtained in step S3 in 25ml of N-methylpyrrolidone, cast it into a film in a flat glass tank, dry it, remove it and soak it in 2mol / L dilute hydrochloric acid solution for 22h, wash it with deionized water to obtain a cation exchange membrane with a thickness of 100μm.

[0039] Preparation Example 2 The preparation method of the cation exchange membrane is the same as that in Preparation Example 1, except that sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate is used instead of sodium p-chlorobenzoate in equimolar amounts.

[0040] Preparation Example 3 The preparation method of the cation exchange membrane is the same as that in Preparation Example 1, except that 0.07 mol of 4,4'-dihydroxybiphenyl and 0.03 mol of glycerol are used.

[0041] Example 1 A method for regenerating acidic etching waste liquid and recovering copper includes the following steps: mixing 1 kg of acidic etching waste liquid with 0.05 g of ascorbic acid as the anolyte; mixing 1 kg of acidic etching waste liquid with deionized water to achieve a copper ion concentration of 32 g / L as the catholyte; and adding the mixture to an electrolytic cell for electrolytic treatment (DC voltage 6V, current density 900 A / dm³). 2 The electrolysis temperature was 55°C and the electrolysis time was 7 hours. The anolyte and catholyte were mixed to obtain a regenerated acidic etching solution. The solid on the cathode was peeled off to obtain metallic copper. The anode chamber and cathode chamber of the electrolytic cell were separated by a cation exchange membrane. The cation exchange membrane was prepared by Preparation Example 1.

[0042] Example 2 A method for regenerating acidic etching waste liquid and recovering copper includes the following steps: mixing 1 kg of acidic etching waste liquid with 0.01 g of ascorbic acid as the anolyte; mixing 1 kg of acidic etching waste liquid with deionized water to achieve a copper ion concentration of 30 g / L as the catholyte; and adding the mixture to an electrolytic cell for electrolytic treatment (DC voltage 5V, current density 800 A / dm³). 2The electrolysis temperature was 50°C and the electrolysis time was 10 h. The anolyte and catholyte were mixed to obtain a regenerated acidic etching solution. The solid on the cathode was peeled off to obtain metallic copper. The anode chamber and cathode chamber of the electrolytic cell were separated by a cation exchange membrane. The cation exchange membrane was prepared by Preparation Example 1.

[0043] Example 3 A method for regenerating acidic etching waste liquid and recovering copper includes the following steps: mixing 1 kg of acidic etching waste liquid with 0.1 g of ascorbic acid as the anolyte; mixing 1 kg of acidic etching waste liquid with deionized water to achieve a copper ion concentration of 35 g / L as the catholyte; and adding the mixture to an electrolytic cell for electrolytic treatment (DC voltage 7V, current density 1000 A / dm³). 2 The electrolysis temperature was 60°C and the electrolysis time was 5 hours. The anolyte and catholyte were mixed to obtain a regenerated acidic etching solution. The solid on the cathode was peeled off to obtain metallic copper. The anode chamber and cathode chamber of the electrolytic cell were separated by a cation exchange membrane. The cation exchange membrane was prepared by Preparation Example 1.

[0044] Example 4 A method for regenerating acidic etching waste liquid and recovering copper is described, with the specific implementation method being the same as in Example 1, except that the cation exchange membrane is prepared in Preparation Example 2.

[0045] Example 5 A method for regenerating acidic etching waste liquid and recovering copper is described, with the specific implementation method being the same as in Example 1, except that the cation exchange membrane is prepared in Preparation Example 3.

[0046] Example 6 A method for regenerating acidic etching waste liquid and recovering copper, the specific implementation method is the same as in Example 1, except that the current density is 1200A / dm. 2 .

[0047] Comparative Example 1 A method for regenerating acidic etching waste liquid and recovering copper is described, with the specific implementation method being the same as in Example 1, except that a perfluorosulfonic acid membrane is used as the cation exchange membrane.

[0048] Comparative Example 2 A method for regenerating acidic etching waste liquid and recovering copper, the specific implementation method is the same as in Example 1, except that ascorbic acid is not added.

[0049] Performance testing: (1) Copper powder purity: Indirect iodometric method; (2) Etching rate of the regenerated etching solution: Tested according to paragraphs

[0077] to

[0082] of the CN116333744B specification; The process methods of each embodiment and comparative example were tested according to the above method, and the results are shown in Table 1.

[0050] Table 1

[0051] According to the data in Table 1, the etching solutions obtained by the methods in Examples 1-3 have a fast etching rate and high copper powder purity. In Example 4, the use of equimolar sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate instead of sodium p-chlorobenzoate resulted in a low amount of copper ions being deposited, thus reducing the performance of the regenerated etching solution and the etching rate. In Example 5, the change in the molar ratio of 1,4-difluorobenzene, 4,4'-dihydroxybiphenyl, and glycerol resulted in a low amount of copper ions being deposited, thus reducing the performance of the regenerated etching solution and the etching rate. In Example 6, the change in current density resulted in a decrease in the purity of the copper powder. In Comparative Example 1, the use of a perfluorosulfonic acid membrane as a cation exchange membrane resulted in a low amount of copper ions being deposited, thus reducing the performance of the regenerated etching solution and the etching rate. In Comparative Example 2, the absence of ascorbic acid resulted in a decrease in the purity of the copper powder, and the increase in byproduct impurities in the etching solution also reduced the performance of the etching solution.

[0052] (3) Bursting strength: The cation exchange membranes and perfluorosulfonic acid membranes prepared in Examples 1 to 3 were soaked in 0.5 mol / L sodium chloride solution for 5 h, and thoroughly washed with ion-exchanged water. Without drying the membranes, the bursting strength was tested using a Mullen bursting tester according to JIS-P8112. The results are shown in Table 2.

[0053] Table 2

[0054] According to the data in Table 2, the cation exchange membranes prepared in Examples 1-3 of this application have higher burst strength and better mechanical properties than commercially available perfluorosulfonic acid membranes.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for regenerating acidic etching waste liquid and recovering copper, characterized in that, The process includes the following steps: mixing the first acidic etching waste liquid with ascorbic acid as the anolyte, mixing the second acidic etching waste liquid with deionized water as the catholyte, adding the mixture to an electrolytic cell for electrolytic treatment, mixing the anolyte and catholyte to obtain a regenerated acidic etching solution, and stripping the solid from the cathode to obtain metallic copper. The anode chamber and cathode chamber of the electrolytic cell are separated by a cation exchange membrane; The cation exchange membrane is prepared from a compound represented by Formula I. （Ⅰ）； Where z = x + y, and x, y, and z are integers.

2. The method for regenerating acidic etching waste liquid and recovering copper according to claim 1, characterized in that, The mass ratio of the first acidic etching waste liquid to ascorbic acid is 1:(0.00001~0.0001).

3. The method for regenerating acidic etching waste liquid and recovering copper according to claim 1, characterized in that, The second acidic etching waste liquid is mixed with deionized water to make the copper ion concentration in the catholyte 30~35g / L.

4. The method for regenerating acidic etching waste liquid and recovering copper according to claim 1, characterized in that, The DC voltage for electrolysis is 5~7V.

5. The method for regenerating acidic etching waste liquid and recovering copper according to claim 1, characterized in that, The current density of the electrolysis is 800~1000 A / dm³. 2 .

6. The method for regenerating acidic etching waste liquid and recovering copper according to claim 1, characterized in that, The electrolysis temperature is 50~60℃.

7. The method for regenerating acidic etching waste liquid and recovering copper according to claim 1, characterized in that, The method for preparing the cation exchange membrane includes the following steps: S1. Under an inert protective gas atmosphere, 1,4-difluorobenzene, 4,4'-dihydroxybiphenyl, glycerol and potassium carbonate are mixed, N,N-dimethylformamide and toluene are added and stirred, the mixture is heated to 140~150℃ and stirred at a constant temperature for 24~28h, cooled to room temperature, added to deionized water, filtered, washed and dried to obtain product A; S2. Under an inert protective gas atmosphere, product A obtained in step S1 is mixed with N-methylpyrrolidone and added to N,N-dimethylformamide, followed by potassium carbonate, sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate and sodium p-chlorobenzoate. The mixture is heated to 140~150℃ and stirred for 3~4 hours. After cooling to room temperature, the mixture is dialyzed through a dialysis bag and dried to obtain product B. S3. The product B obtained in step S2 is mixed with methacrylic acid and acrylate and added to toluene. Then an initiator is added, the temperature is raised to 70~80℃ and stirred for 1~3h. Then centrifuge, filter, wash and dry to obtain the compound shown in Formula I. S4. Dissolve the compound of formula I obtained in step S3 in N-methylpyrrolidone, cast it into a film in a flat glass tank, dry it, remove it and soak it in dilute hydrochloric acid solution for 20-24 hours, wash it with deionized water to obtain a cation exchange membrane.

8. The method for regenerating acidic etching waste liquid and recovering copper according to claim 7, characterized in that, In step S1, the molar ratio of 1,4-difluorobenzene, 4,4'-dihydroxybiphenyl and glycerol is 1:(0.4~0.6):(0.4~0.6).

9. The method for regenerating acidic etching waste liquid and recovering copper according to claim 7, characterized in that, In step S2, the molar ratio of product A to sodium 2-(4-chlorophenoxy)-1,1,2,2-tetrafluoroethane-1-sulfonate is 1:(1~1.2).

10. The method for regenerating acidic etching waste liquid and recovering copper according to claim 7, characterized in that, In step S2 and step S3, the mass ratio of product B, methacrylic acid, and acrylate is 1:(0.1~0.3):(0.1~0.3).

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