Comprehensive electroplating wastewater treatment method

Abstract

The invention relates to a treatment method of comprehensive electroplating wastewater. The treatment method comprises the following steps: (1) discharging wastewater in an electroplating tank into a wastewater tank containing an adsorption resin compound; (3) carrying out adsorption treatment on the electroplating wastewater through the adsorption resin compound; (3) acid liquor recovery; the adsorption resin compound comprises lignin composite resin and chlorine ball composite resin, and the chlorine ball composite resin is prepared from carboxyl modified resin and 1, 2-dichloroethane. The method has the effect of improving the adsorption efficiency of the metal ions in the plating solution wastewater.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment, and in particular to a method for treating comprehensive electroplating wastewater. Background Technology

[0002] Electroplating is a process that uses electrolysis to deposit a layer of metal or alloy onto a metal surface. The resulting electroplating wastewater includes all wastewater generated in the workshop during each step of the electroplating production process. The electroplating process is generally divided into a pretreatment stage, an electroplating stage, and a post-treatment stage. The pretreatment stage mainly removes oil, oxide layers, and other substances from the surface of the workpiece, while the post-treatment stage cleans and passivates the electroplated workpiece.

[0003] However, during the electroplating process, less than 40% of the metal is successfully used in the plated parts. As a result, a large amount of high-concentration metal wastewater is generated in this process. With the continuous development of industry, the requirements for electroplating technology are constantly increasing, and the composition of electroplating wastewater is becoming more and more complex. It is difficult to further improve the treatment efficiency of electroplating wastewater doped with multiple metal ions. Summary of the Invention

[0004] To further improve the treatment efficiency of electroplating wastewater, this application provides a comprehensive method for treating electroplating wastewater.

[0005] The method for treating comprehensive electroplating wastewater provided in this application adopts the following technical solution: A comprehensive method for treating electroplating wastewater includes the following steps: (1) Discharge the wastewater from the electroplating tank into a wastewater tank containing an adsorption resin complex; (3) Electroplating wastewater is treated by adsorption of adsorption resin complex; (3) Acid recovery; The adsorption resin complex comprises lignin composite resin and chlorine ball composite resin, wherein the raw materials of the chlorine ball composite resin include carboxyl-modified resin and 1,2-dichloroethane.

[0006] By employing the above-mentioned technical solution, electroplating wastewater is adsorbed using an adsorption resin composite to remove metal ions from the wastewater. Specifically, the adsorption effect on different metal ions in the wastewater is further enhanced by combining lignin composite resin and chlorinated sphere composite resin. The lignin composite resin exhibits excellent adsorption performance for Cr ions, while the chlorinated sphere composite resin demonstrates good adsorption performance for Ni ions and other heavy metal ions. The combination of the two results in a synergistic adsorption effect. The chlorinated sphere composite resin is prepared by combining a carboxyl-modified resin with 1,2-dichloroethane. The carboxyl-modified resin increases the content of functional groups through group modification, and the post-crosslinking with 1,2-dichloroethane increases the specific surface area of ​​the chlorinated sphere composite resin, retaining more macroporous and mesoporous structures with more suitable pore sizes. This results in more functional groups in the chlorinated sphere resin structure and a more uniform distribution, thereby increasing the adsorption capacity of the adsorption resin composite, reducing the concentration of metal ions in the wastewater, and further improving the efficiency of the adsorption resin composite in wastewater treatment.

[0007] Preferably, the carboxyl-modified resin is prepared by the following method: The chloromethylated styrene-divinylbenzene copolymer was swollen in 1,2-dichloroethane, followed by the addition of hexamethylenetetramine. The mixture was heated and stirred to react. After the reaction was completed, the product was filtered out, mixed with sodium chloroacetate, and sodium hydroxide was added. The mixture was heated and stirred to react. After the reaction was completed, the mixture was filtered, washed to remove impurities, and dried to obtain the carboxyl-modified resin.

[0008] By adopting the above technical solution, imino and carboxyl groups are introduced into the resin, which can interact with metal ions in the wastewater, thereby complexing the metal ions and reducing the concentration of metal ions in the electroplating wastewater, thus improving the treatment and adsorption effect of the electroplating wastewater.

[0009] Preferably, the adsorption resin is prepared by the following method: The carboxyl-modified resin was swollen in 1,2-dichloroethane, followed by the addition of ferric chloride. The mixture was heated and stirred to react. After the reaction was completed, the mixture was cooled and washed to obtain the chlorine-based composite resin.

[0010] By adopting the above technical solution, after the carboxyl-modified resin is crosslinked with 1,2-dichloroethylene, a large number of chloromethyl groups participate in the reaction, which further increases the specific surface area of ​​the crosslinked resin. The microporous structure of the prepared chlorosphere composite resin is richer, which has a significant promoting effect on the adsorption capacity of nickel complexes in wastewater and can further improve the adsorption rate of chlorosphere resin, thereby improving the treatment rate of electroplating wastewater.

[0011] Preferably, the lignin composite resin includes lignin, pyrogallol, and tetraethylenepentamine.

[0012] By adopting the above technical solution, lignin is mainly composed of three phenylpropane units. The polycatechin contained in pyrogallol is a novel polymer inspired by mussel adhesion proteins. The lignin composite resin is prepared by reacting materials containing catechol groups with materials containing amino groups. It has a large number of active groups and can capture target particles through chelation or electrostatic attraction, thereby further improving the adsorption performance of metal ions in electroplating wastewater.

[0013] Preferably, the lignin composite resin is prepared by the following method: After mixing lignin with pyrogallol, sulfuric acid was added, and after stirring, acetone was added to react. Then, excess acetone was removed by dialysis, followed by centrifugation and freeze-drying to obtain phenolic lignin. Phenolic lignin was mixed with water, ultrasonically dispersed, and tetraethylenepentamine was added. The mixture was magnetically stirred and reacted, followed by centrifugation and freeze-drying to obtain lignin composite resin.

[0014] By adopting the above technical solution, pyrogallol is used to phenolize lignin in the presence of acetone. The phenolized lignin is then reacted with tetraethylenepentamine to prepare lignin composite resin. The lignin composite resin has a large specific surface area and good adsorption performance for Cr ions in electroplating wastewater. It can convert hexavalent Cr ions into trivalent Cr ions and further remove them, thereby effectively reducing the concentration of metal ions in the waste liquid.

[0015] Preferably, the mass ratio of lignin, pyrogallol and tetraethylenepentamine is 1:(1.05-1.15):3.8.

[0016] By adopting the above technical solution, and optimizing the mass ratio of lignin, pyrogallol and tetraethylenepentamine within the above range, the overall performance of the prepared lignin composite resin can be further improved.

[0017] Preferably, the concentration of the lignin composite resin during the adsorption treatment is 140-160 mg / g.

[0018] By adopting the above technical solution, and preferably within the above-mentioned range, the concentration of lignin composite resin can further promote the adsorption efficiency and adsorption stability of metal ions in electroplating waste liquid.

[0019] Preferably, the concentration of the chlorine-based composite resin during the adsorption treatment is 200-250 mg / g.

[0020] By adopting the above technical solution, and preferably using a concentration of chlorine-based composite resin within the above range, the adsorption efficiency and adsorption stability of metal ions in electroplating wastewater can be further improved.

[0021] Preferably, the temperature during the adsorption treatment is 27-31℃.

[0022] By adopting the above technical solution, and preferably keeping the temperature during adsorption treatment within the above range, the adsorption efficiency for wastewater treatment can be further improved.

[0023] Preferably, the pH value of the electroplating wastewater is 3.5-4 during the adsorption treatment.

[0024] By adopting the above-mentioned technical methods, the pH value of electroplating wastewater is preferably within the above-mentioned range when it is treated, which can further enhance the adsorption of metal ions in the electroplating solution, thereby improving the treatment efficiency of electroplating wastewater.

[0025] In summary, this application includes at least one of the following beneficial technical effects: 1. In this application, metal ions in electroplating wastewater are adsorbed using an adsorption resin composite. The adsorption resin composite is prepared by combining lignin composite resin and chlorine sphere composite resin, which can synergistically adsorb metal ions in the plating wastewater. The lignin composite resin exhibits good adsorption performance for Cr ions in the electroplating wastewater, while the chlorine sphere composite resin has a good adsorption effect on Ni ions. Furthermore, by modifying the carboxyl group of the resin with 1,2-dichloroethane, the specific surface area of ​​the chlorine sphere composite resin can be further increased, resulting in a more uniform distribution of functional groups in the chlorine sphere resin structure. This enhances the adsorption capacity of the chlorine sphere resin and further improves the treatment efficiency of the electroplating wastewater. 2. Lignin is mainly composed of three phenylpropane units. Pyrogallol contains polycatechin, a novel polymer inspired by mussel adhesive proteins. It is prepared by reacting materials containing catechin groups with materials containing amino groups. It has a large number of active groups and can capture target particles through chelation or electrostatic attraction, thereby further improving the adsorption performance of metal ions in electroplating wastewater.

[0026] 3. Pyrogallol phenolizes lignin in the presence of acetone. The phenolized lignin is then reacted with tetraethylenepentamine to prepare lignin composite resin. The lignin composite resin has a large specific surface area and good adsorption performance for Cr ions in electroplating wastewater. It can convert hexavalent Cr ions into trivalent Cr ions and remove them, thereby improving the treatment efficiency of electroplating wastewater. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the embodiments: Raw material description: All raw materials used in the examples are commercially available.

[0028] Example 1 Preparation of lignin composite resin: 17.09 g of lignin (CAS No.: 8068-05-1) and 17.95 g of pyrogallol (CAS No.: 87-66-1) were mixed, and 80 mL of 72% sulfuric acid was added. After stirring, 10 mL of acetone was added, and the mixture was reacted for 2 h. Then, excess acetone was removed by dialyzing until the system became neutral. After centrifugation, the mixture was freeze-dried at -20 °C for 12 h to obtain phenolic lignin. The prepared phenolic lignin was added to 3 L of deionized water, ultrasonically dispersed, and then 64.96 g of tetraethylenepentamine (CAS No.: 112-57-2) was added. The mixture was magnetically stirred for 72 h, and then centrifuged and freeze-dried at -20 °C for 12 h to obtain lignin composite resin.

[0029] Preparation of carboxyl-modified resins: 40g of chloromethylated styrene-divinylbenzene copolymer (CAS No.: 55844-94-5) was swollen in 1,2-dichloroethane (CAS No.: 107-06-2) for 12h. 4000mL of hexamethylenetetramine (CAS No.: 100-97-0) was added, the temperature was raised to 50℃, and the reaction was stirred for 4h. After the reaction was completed, the product was filtered out. The product was mixed with 50g of sodium chloroacetate (CAS No.: 3926-62-3), and 1600mL of sodium hydroxide was added. The temperature was raised to 60℃, and the reaction was stirred for 5h. After the reaction was completed, the product was filtered out, and impurities were removed by washing three times alternately with deionized water and ethanol. The product was dried at 60℃ to obtain carboxyl-modified resin.

[0030] Preparation of chlorinated sphere composite resin: The carboxyl-modified resin was swollen in 1,2-dichloroethane for 12 hours, followed by the addition of 25 g of ferric chloride. The mixture was stirred at 80 °C for 5 hours. After the reaction was completed, the mixture was cooled to 25 °C and washed alternately with deionized water and ethanol to prepare the chlorinated sphere composite resin.

[0031] Adsorption resin complex After mixing chlorine-based composite resin and lignin-based composite resin, an adsorption resin complex is obtained.

[0032] Electroplating wastewater treatment: (1) Discharge the wastewater from the electroplating tank into a wastewater tank containing an adsorption resin complex; (3) Electroplating wastewater is treated by adsorption of adsorption resin complex; (3) Acid recovery; The concentration of chlorinated polyol composite resin in the wastewater pool was 200 mg / g, and the concentration of lignin composite resin in the wastewater pool was 140 mg / g. During the adsorption treatment, the pH value of the waste liquid was 3.5, and the adsorption treatment temperature was 27℃.

[0033] Example 2 Preparation of lignin composite resin: 16.81g of lignin and 19.33g of pyrogallol were mixed, and 80mL of 72% sulfuric acid was added. After stirring, 50mL of acetone was added, and the mixture was reacted for 2h. Then, excess acetone was removed by dialysis until the system became neutral. After centrifugation, the mixture was freeze-dried at -20℃ for 12h to obtain phenolic lignin. The prepared phenolic lignin was added to 3L of deionized water, ultrasonically dispersed, and then 63.86g of tetraethylenepentamine was added. The mixture was magnetically stirred for 72h, and then centrifuged and freeze-dried at -20℃ for 12h to obtain lignin composite resin.

[0034] Preparation of carboxyl-modified resins: 40g of chloromethylated styrene-divinylbenzene copolymer was swollen in 1,2-dichloroethane for 12h, then 4000mL of hexamethylenetetramine was added, the temperature was raised to 50℃, and the reaction was stirred for 4h. After the reaction was completed, the product was filtered out, and the product was mixed with 50g of sodium chloroacetate and 1600mL of sodium hydroxide was added. The temperature was raised to 60℃, and the reaction was stirred for 5h. After the reaction was completed, the product was filtered out, and impurities were removed by washing three times alternately with deionized water and ethanol. The product was dried at 60℃ to obtain carboxyl-modified resin.

[0035] Preparation of chlorinated sphere composite resin: The carboxyl-modified resin was swollen in 1,2-dichloroethane for 12 hours, followed by the addition of 25 g of ferric chloride. The mixture was stirred at 80 °C for 5 hours. After the reaction was completed, the mixture was cooled to 25 °C and washed alternately with deionized water and ethanol to prepare the chlorinated sphere composite resin.

[0036] Adsorption resin complex After mixing chlorine-based composite resin and lignin-based composite resin, an adsorption resin complex is obtained.

[0037] Electroplating wastewater treatment: (1) Discharge the wastewater from the electroplating tank into a wastewater tank containing an adsorption resin complex; (3) Electroplating wastewater is treated by adsorption of adsorption resin complex; (3) Acid recovery; The concentration of chlorine-based composite resin in the wastewater pool was 250 mg / g, and the concentration of lignin-based composite resin in the wastewater pool was 160 mg / g. During the adsorption treatment, the pH value of the waste liquid was 4, and the adsorption treatment temperature was 31℃.

[0038] Example 3 Preparation of lignin composite resin: 16.95g of lignin and 18.64g of pyrogallol were mixed, and 80mL of 72% sulfuric acid was added. After stirring, 10mL of acetone was added, and the mixture was reacted for 2h. Then, excess acetone was removed by dialysis until the system became neutral. After centrifugation, the mixture was freeze-dried at -20℃ for 12h to obtain phenolic lignin. The prepared phenolic lignin was added to 3L of deionized water, ultrasonically dispersed, and then 64.41g of tetraethylenepentamine was added. The mixture was magnetically stirred for 72h, and then centrifuged and freeze-dried at -20℃ for 12h to obtain lignin composite resin.

[0039] Preparation of carboxyl-modified resins: 40g of chloromethylated styrene-divinylbenzene copolymer was swollen in 1,2-dichloroethane for 12h, then 4000mL of hexamethylenetetramine was added, the temperature was raised to 50℃, and the reaction was stirred for 4h. After the reaction was completed, the product was filtered out, and the product was mixed with 50g of sodium chloroacetate and 1600mL of sodium hydroxide was added. The temperature was raised to 60℃, and the reaction was stirred for 5h. After the reaction was completed, the product was filtered out, and impurities were removed by washing three times alternately with deionized water and ethanol. The product was dried at 60℃ to obtain carboxyl-modified resin.

[0040] Preparation of chlorinated sphere composite resin: The carboxyl-modified resin was swollen in 1,2-dichloroethane for 12 hours, followed by the addition of 25 g of ferric chloride. The mixture was stirred at 80 °C for 5 hours. After the reaction was completed, the mixture was cooled to 25 °C and washed alternately with deionized water and ethanol to prepare the chlorinated sphere composite resin.

[0041] Adsorption resin complex After mixing chlorine-based composite resin and lignin-based composite resin, an adsorption resin complex is obtained.

[0042] Electroplating wastewater treatment: (1) Discharge the wastewater from the electroplating tank into a wastewater tank containing an adsorption resin complex; (3) Electroplating wastewater is treated by adsorption of adsorption resin complex; (3) Acid recovery; The concentration of chlorine-based composite resin in the wastewater pool was 225 mg / g, and the concentration of lignin-based composite resin in the wastewater pool was 150 mg / g. During the adsorption treatment, the pH value of the waste liquid was 3.7, and the adsorption treatment temperature was 29℃.

[0043] Example 4 Example 4 is based on Example 3. The difference between Example 4 and Example 3 is that in Example 4, when preparing the lignin composite resin, the amount of lignin used is 17.54g, the amount of pyrogallol used is 15.79g, and the amount of tetraethylenepentamine used is 66.67g.

[0044] Example 5 Example 5 is based on Example 3. The difference between Example 5 and Example 3 is that in Example 5, when preparing the lignin composite resin, the amount of lignin used is 16.39g, the amount of pyrogallol used is 21.31g, and the amount of tetraethylenepentamine used is 62.3g.

[0045] Example 6 Example 6 is based on Example 3. The difference between Example 6 and Example 3 is that the concentration of lignin composite resin in Example 6 is 120 mg / g.

[0046] Example 7 Example 7 is based on Example 3. The difference between Example 7 and Example 3 is that the concentration of lignin composite resin in Example 7 is 180 mg / g.

[0047] Example 8 Example 8 is based on Example 3. The difference between Example 8 and Example 3 is that the concentration of the chlorine-based composite resin in Example 8 is 170 mg / g.

[0048] Example 9 Example 9 is based on Example 3. The difference between Example 9 and Example 3 is that the concentration of the chlorine complex in Example 9 is 280 mg / g.

[0049] Example 10 Example 10 is based on Example 3. The difference between Example 10 and Example 3 is that the treatment temperature for electroplating wastewater in Example 10 is 22°C.

[0050] Example 11 Example 11 is based on Example 3. The difference between Example 11 and Example 3 is that the treatment temperature for electroplating wastewater in Example 11 is 36°C.

[0051] Example 12 Example 12 is based on Example 3. The difference between Example 12 and Example 3 is that the pH value of the electroplating waste liquid in Example 12 is 3.

[0052] Example 13 Example 13 is based on Example 3. The difference between Example 13 and Example 3 is that the pH value of the electroplating waste liquid in Example 13 is 4.5.

[0053] Example 14 Comparative Example 14 is based on Example 3. The difference between Example 14 and Example 3 is that in Example 14, the lignin composite resin is replaced with ordinary lignin.

[0054] Comparative Example 1 Comparative Example 1 is based on Example 3. In Comparative Example 1, when preparing the chlorinated sphere composite resin, the carboxyl-modified resin was replaced with a common resin.

[0055] Comparative Example 2 Comparative Example 2 is based on Example 3, except that the adsorption resin complex is replaced with lignin composite resin.

[0056] Comparative Example 3 Comparative Example 3 is based on Example 3, except that the adsorption resin complex is replaced with chlorine ball composite resin.

[0057] Performance testing The acid solutions treated in Examples 1-14 and Comparative Examples 1-3 were subjected to the following tests: Using the "GB 21900-2008 Electroplating Pollutant Emission Standard" as the standard, the components in the electroplating wastewater before treatment and the acid solution of the treated wastewater were tested and compared with the standard. The test results were filled in Table 1.

[0058] Table 1. Test results of acid samples after treatment in Examples 1-14 and Comparative Examples 1-3. As shown in Table 1, the acid concentration decreased after treatment in Examples 1-3, indicating that the electroplating wastewater treatment method of this application has good metal ion adsorption efficiency, thereby improving the treatment performance of electroplating wastewater.

[0059] As shown in Table 1, in Examples 4 and 5, the mass ratio of lignin, pyrogallol, and tetraethylenepentamine during the preparation of lignin composite resin was not within the range specified in this application. When the content of pyrogallol was too low, the content of phenolic groups in the resin was too low, and the content of active groups in the resin decreased significantly. It was difficult to further enhance the attraction of metal ions in the electroplating wastewater, and therefore the concentration of metal ions in the electroplating wastewater was difficult to further decrease. When the content of pyrogallol was too high, the molecular weight of the prepared lignin composite resin decreased, thereby reducing the yield and affecting the adsorption stability of the lignin resin, which in turn affected the adsorption performance of metal ions in the electroplating wastewater. Therefore, the performance of Examples 4 and 5 was reduced.

[0060] In Examples 6 and 7, the concentrations of lignin composite resin in the wastewater tank were not within the range defined in this application. In Examples 8 and 9, the concentrations of chlorine-based composite resin were not within the range defined in this application. When the concentration of lignin composite resin or chlorine-based composite resin was too high, it affected the adsorption capacity of the adsorption resin composite, making it difficult to achieve equilibrium adsorption and thus affecting the overall adsorption efficiency. When the concentration of lignin composite resin or chlorine-based composite resin was too low, the adsorption resin composite system could not provide more adsorption sites to bind with metal ions in the waste liquid, thus affecting the adsorption performance of metal ions in the electroplating waste liquid and making it difficult to further achieve an equilibrium adsorption state. Therefore, the metal ion concentrations in Examples 6-9 were difficult to decrease further.

[0061] In Examples 10 and 11, the treatment temperatures for electroplating wastewater were not within the range specified in this application. When the temperature was too low, the adsorption active sites in the adsorption resin complex were difficult to be further exposed, making it difficult to further promote the adsorption performance of metal ions in the electroplating wastewater. When the temperature was too high, the adsorption treatment temperature would be too high, affecting the overall stability of the adsorption resin complex and making it difficult to promote the adsorption efficiency of metal ions. Therefore, the metal ion concentration of the acid solution after wastewater treatment in Examples 10 and 11 was difficult to further decrease.

[0062] In Examples 12 and 13, the pH values ​​of the wastewater treated during electroplating wastewater treatment were not within the range defined in this application; when the pH value of the electroplating wastewater is too low, it is difficult to further promote the adsorption of HCrO4 by the adsorption resin complex. - The electrostatic interaction between ions makes it difficult to further improve the adsorption capacity of Cr ions, which affects the treatment efficiency of metal ions in electroplating wastewater. When the pH value of the wastewater is too high during electroplating wastewater treatment, nickel ions in the wastewater undergo hydrolysis to generate nickel hydroxide precipitate, which is not conducive to the adsorption performance of metal ions in the electroplating wastewater. Therefore, in Examples 12 and 13, the concentration of metal ions in the treated acid solution is difficult to decrease further.

[0063] In Example 14, the lignin composite resin was replaced with ordinary lignin. The lignin that has not undergone phenolic modification is difficult to crosslink further, and the active groups on the surface of the system are difficult to be further enhanced. Moreover, the lignin that has not undergone phenolic modification is difficult to capture metal ions through chelation or electrostatic capture. Therefore, the absorption performance of metal ions in electroplating waste liquid is difficult to be further enhanced. Hence, the concentration of metal ions in the acid solution after treatment in Example 14 is difficult to be further reduced.

[0064] In Comparative Example 1, the carboxyl-modified resin was replaced with ordinary resin. The active groups on the surface of the unmodified resin were difficult to further enhance, making it difficult to further adsorb metal ions in the electroplating wastewater. Therefore, the concentration of metal ions in the acid solution in Comparative Example 1 was difficult to further decrease.

[0065] In Comparative Example 2, no chlorine-based composite resin was involved in the adsorption of metal ions in the plating wastewater. In Comparative Example 3, no lignin-based composite resin was involved in the adsorption of metal ions in the electroplating wastewater. The adsorption efficiency of a single resin material for metal ions in the plating wastewater is difficult to further improve. Therefore, in Comparative Examples 2 and 3, the concentration of metal ions in the acid solution after treatment of the electroplating wastewater is difficult to further decrease.

[0066] This specific embodiment is merely an explanation of this application and is not intended to limit it. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification but must be determined according to the scope of the claims.

Claims

1. A method for treating comprehensive electroplating wastewater, characterized in that: The steps include: (1) Discharging wastewater from the electroplating tank into a wastewater tank containing an adsorption resin complex; (3) Adsorption treatment of electroplating wastewater by adsorption resin complex; (3) Acid recovery; The adsorption resin complex comprises lignin composite resin and chlorine ball composite resin, and the raw materials of the chlorine ball composite resin comprise carboxyl modified resin and 1,2-dichloroethane.

2. The method for treating comprehensive electroplating wastewater according to claim 1, characterized in that: The carboxyl modified resin is prepared by the following method: The chloromethylated styrene-divinylbenzene copolymer is swollen in 1,2-dichloroethane, and then hexamethylenetetramine is added. The temperature is raised and stirred for reaction. After the reaction is completed, the product is filtered out, and the product is mixed with sodium chloroacetate, and sodium hydroxide is added. The temperature is raised and stirred for reaction. After the reaction is completed, the impurities are removed by filtering and washing, and then the carboxyl-modified resin is obtained by drying.

3. The method for treating comprehensive electroplating wastewater according to claim 2, characterized in that: The adsorption resin is prepared by the following method: The carboxyl modified resin is swollen in 1,2-dichloroethane, and then ferric chloride is added, heated and stirred for reaction, cooled after the reaction is completed, and washed to obtain a chlorine ball composite resin.

4. The method for treating comprehensive electroplating wastewater according to claim 1, characterized in that: The lignin composite resin comprises lignin, pyrogallol and tetraethylenepentamine.

5. A method for treating comprehensive electroplating wastewater according to claim 4, characterized in that: The lignin composite resin is prepared by the following method: After mixing lignin with pyrogallol, sulfuric acid is added, and acetone is added after stirring to react, followed by dialysis to remove excess acetone, followed by centrifugation and freeze-drying to obtain phenolic lignin; phenolic lignin is mixed with water, ultrasonically dispersed, tetraethylenepentamine is added, magnetic stirring is performed to react, followed by centrifugation and freeze-drying to obtain lignin composite resin.

6. A method for treating comprehensive electroplating wastewater according to claim 5, characterized in that: The mass ratio of the lignin, pyrogallol and tetraethylenepentamine is 1:(1.05-1.15):3.

8.

7. The method for treating comprehensive electroplating wastewater according to claim 1, characterized in that: The concentration of the lignin composite resin during the adsorption treatment is 140-160 mg / g.

8. The method for treating comprehensive electroplating wastewater according to claim 1, characterized in that: The concentration of the chlorine ball composite resin during the adsorption treatment is 200-250 mg / g.

9. The method for treating comprehensive electroplating wastewater according to claim 1, characterized in that: The temperature during the adsorption treatment is 27-31°C.

10. The method for treating comprehensive electroplating wastewater according to claim 1, characterized in that: During the adsorption treatment, the pH value of the electroplating wastewater is 3.5-4.

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