Treatment method of wastewater containing heavy metals

Abstract

The invention provides a treatment method of wastewater containing heavy metals, and belongs to the technical field of wastewater treatment. The wastewater is firstly filtered, then iron-carbon micro-electrolysis is carried out on the wastewater to destroy the structure of organic matters in the wastewater, the complexing effect of the organic matters in the wastewater on heavy metal ions is reduced, and the subsequent adsorption reaction of the heavy metal ions and an adsorbent is facilitated; the bentonite, the chitosan, the polyaluminum chloride and the fly ash are compounded to serve as an adsorbent to remove heavy metal ions in the wastewater, and the bentonite has a large specific surface area and ion exchange performance and can adsorb the heavy metal ions; chitosan contains a large number of active groups such as amino groups and hydroxyl groups, and can be subjected to chelation reaction with heavy metal ions; polyaluminum chloride is used as a flocculating agent and can promote precipitation of heavy metal ions; the fly ash has a porous structure and can also have a certain adsorption effect on the heavy metal ions, and meanwhile, the four components have a synergistic effect, so that the removal rate of the heavy metal ions in the heavy metal-containing wastewater is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for treating wastewater containing heavy metals. Background Art

[0002] A certain amount of heavy metal wastewater is generally produced in the industrial production process. The heavy metals in it will cause serious harm to human health and the environment. Therefore, heavy metal wastewater must be treated before it can be discharged. At present, the main treatment methods for heavy metal wastewater include adsorption, ion exchange or membrane separation. Among them, adsorption is widely used in the treatment of heavy metal wastewater due to its simple method. Commonly used adsorbents are generally polymer aluminum chloride and polyacrylamide, but the removal rate of heavy metals in wastewater still needs to be further improved. Summary of the invention

[0003] The purpose of the present invention is to provide a method for treating heavy metal-containing wastewater. The treatment method provided by the present invention has a better removal effect on heavy metals in heavy metal wastewater.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for treating heavy metal-containing wastewater, comprising the following steps:

[0006] (1) filtering the heavy metal-containing wastewater to obtain filtered wastewater;

[0007] (2) subjecting the filtered wastewater obtained in step (1) to iron-carbon micro-electrolysis to obtain electrolyzed wastewater;

[0008] (3) mixing the electrolytic wastewater obtained in step (2) with an adsorbent, subjecting the mixture to adsorption treatment and then filtering the mixture to obtain purified water;

[0009] The adsorbent comprises the following components by weight: 8 to 12 parts of bentonite, 2 to 5 parts of chitosan, 9 to 13 parts of polyaluminium chloride and 5 to 9 parts of fly ash.

[0010] Preferably, the pH value of the heavy metal-containing wastewater in step (1) is 3-7.

[0011] Preferably, the heavy metal ions in the heavy metal-containing wastewater in step (1) include one or more of lead ions, copper ions and nickel ions; and the concentrations of lead ions, copper ions and nickel ions in the heavy metal-containing wastewater are independently 15 to 100 mg / L.

[0012] Preferably, in step (2), the temperature of the iron-carbon micro-electrolysis is 30-60° C., the time of the iron-carbon micro-electrolysis is 20-40 min, the iron-carbon mass ratio in the iron-carbon micro-electrolysis filler is 1-10:1, and the particle size of the iron-carbon micro-electrolysis filler is 1-30 mm.

[0013] Preferably, air is introduced during the iron-carbon micro-electrolysis process in step (2); the volume ratio of air to water is 3 to 6:1.

[0014] Preferably, the bentonite in step (3) is sodium bentonite; and the particle size of the bentonite is 50 to 75 μm.

[0015] Preferably, the particle size of chitosan in step (3) is 20-200 mesh.

[0016] Preferably, the particle size of the fly ash in step (3) is 10 to 100 meshes.

[0017] Preferably, in step (3), the ratio of the mass of the adsorbent to the volume of the electrolytic wastewater is (0.1-5) g:1L.

[0018] Preferably, the temperature of the adsorption treatment in step (3) is 10 to 30° C., and the time of the adsorption treatment is 20 to 30 minutes.

[0019] The present invention provides a method for treating heavy metal-containing wastewater, comprising the following steps: (1) filtering the heavy metal-containing wastewater to obtain filtered wastewater; (2) subjecting the filtered wastewater obtained in the step (1) to iron-carbon micro-electrolysis to obtain electrolyzed wastewater; (3) mixing the electrolyzed wastewater obtained in the step (2) with an adsorbent, subjecting the mixture to adsorption treatment and filtering to obtain purified water; the adsorbent comprises the following components by weight: 8 to 12 parts of bentonite, 2 to 5 parts of chitosan, 9 to 13 parts of polyaluminium chloride and 5 to 9 parts of fly ash. The invention first filters the wastewater to remove insoluble matter in the wastewater, then performs iron-carbon micro-electrolysis on the wastewater to destroy the structure of organic matter in the wastewater, reduces the complexing effect of organic matter in the wastewater on heavy metal ions, and is more conducive to the subsequent adsorption reaction between heavy metal ions and adsorbents. Bentonite, chitosan, polyaluminium chloride and fly ash are compounded as adsorbents to remove heavy metal ions in the wastewater. Bentonite has a large specific surface area and ion exchange performance and can adsorb heavy metal ions; chitosan contains a large number of active groups such as amino groups and hydroxyl groups and can react with heavy metal ions to form a chelate reaction; polyaluminium chloride is used as a flocculant and can promote the precipitation of heavy metal ions; fly ash The fly ash has a certain adsorption effect on heavy metal ions; after compound use, bentonite and fly ash provide the main adsorption sites and ion exchange sites, which can initially remove some heavy metal ions through adsorption and ion exchange, reduce the concentration of heavy metal ions in wastewater, and create better conditions for the chelation of chitosan. The polyaluminium chloride hydrolysate also provides new adsorption sites. The combination of the four further improves the adsorption opportunity of heavy metals. At the same time, the polyaluminium chloride hydrolysate can promote the coagulation of other substances, and synergize with chitosan to make the flocculation effect better. The four have a synergistic effect, thereby improving the removal rate of heavy metal ions in heavy metal-containing wastewater. The results of the embodiment show that after treatment by the treatment method of the present invention, the removal rate of heavy metal ions in wastewater is above 97%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the removal rate of heavy metals in heavy metal-containing wastewater of Examples 1 to 3 and Comparative Examples 1 to 6. DETAILED DESCRIPTION

[0021] The present invention provides a method for treating heavy metal-containing wastewater, comprising the following steps:

[0022] (1) filtering the heavy metal-containing wastewater to obtain filtered wastewater;

[0023] (2) subjecting the filtered wastewater obtained in step (1) to iron-carbon micro-electrolysis to obtain electrolyzed wastewater;

[0024] (3) mixing the electrolytic wastewater obtained in step (2) with an adsorbent, subjecting the mixture to adsorption treatment and then filtering the mixture to obtain purified water;

[0025] The adsorbent comprises the following components by weight: 8 to 12 parts of bentonite, 2 to 5 parts of chitosan, 9 to 13 parts of polyaluminium chloride and 5 to 9 parts of fly ash.

[0026] The invention filters the heavy metal-containing wastewater to obtain filtered wastewater.

[0027] The present invention has no special limitation on the source of the heavy metal-containing wastewater, and any heavy metal-containing wastewater well known to those skilled in the art may be used.

[0028] In the present invention, the heavy metal ions in the heavy metal-containing wastewater preferably include one or more of lead ions, copper ions and nickel ions.

[0029] In the present invention, the concentrations of lead ions, copper ions and nickel ions in the heavy metal-containing wastewater are preferably independently 15 to 100 mg / L. As an embodiment, the concentrations of lead ions, copper ions and nickel ions in the heavy metal-containing wastewater can be specifically 15 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, 50 mg / L, 60 mg / L, 70 mg / L, 80 mg / L, 90 mg / L or 100 mg / L, respectively.

[0030] In the present invention, the pH value of the heavy metal-containing wastewater is preferably 3 to 7. As an embodiment, the pH value of the heavy metal-containing wastewater may be specifically 3, 4, 5, 6 or 7. The present invention controls the pH value of the heavy metal-containing wastewater within the above range, which can further improve the removal rate of heavy metal ions in the wastewater.

[0031] The present invention has no special limitation on the filtering operation, and the filtering technical schemes well known to those skilled in the art can be used. The present invention first filters the heavy metal-containing wastewater to remove insoluble matter in the wastewater, which is more conducive to the subsequent treatment process and improves the removal rate of heavy metal ions in the wastewater.

[0032] After obtaining the filtered wastewater, the present invention performs iron-carbon micro-electrolysis on the filtered wastewater to obtain electrolyzed wastewater.

[0033] In the present invention, the temperature of the iron-carbon micro-electrolysis is preferably 30-60° C. As an embodiment, the temperature of the iron-carbon micro-electrolysis can be specifically 30° C., 40° C., 50° C. or 60° C.

[0034] In the present invention, the time of the iron-carbon micro-electrolysis is preferably 20 to 40 minutes. As an embodiment, the time of the iron-carbon micro-electrolysis can be specifically 20 minutes, 25 minutes, 30 minutes, 35 minutes or 40 minutes.

[0035] In the present invention, the iron-carbon mass ratio in the iron-carbon micro-electrolysis filler is preferably 1 to 10: 1. As an embodiment, the iron-carbon mass ratio in the iron-carbon micro-electrolysis filler can be specifically 1: 1, 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1 or 10: 1.

[0036] In the present invention, the particle size of the iron-carbon micro-electrolysis filler is preferably 1 to 30 mm. As an embodiment, the particle size of the iron-carbon micro-electrolysis filler can be specifically 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm or 30 mm. The present invention has no special limitation on the source of the iron-carbon micro-electrolysis filler, and commercially available products with parameters within the above ranges well known to those skilled in the art can be used.

[0037] In the present invention, air is preferably introduced during the iron-carbon micro-electrolysis process; the volume ratio of air to water is preferably 3 to 6:1. As an embodiment, the volume ratio of air to water may specifically be 3:1, 4:1, 5:1 or 6:1. The present invention performs iron-carbon micro-electrolysis on the filtered wastewater. During the iron-carbon micro-electrolysis process, highly active substances and electric field effects are generated on the electrode surface, which can destroy the structure of organic matter in the wastewater, reduce the complexation of organic matter in the wastewater to heavy metal ions, and are more conducive to the subsequent adsorption reaction of heavy metal ions with adsorbents. The present invention controls the various parameters of iron-carbon micro-electrolysis within the above range, which can further improve the removal rate of heavy metal ions in the wastewater.

[0038] After obtaining the electrolytic wastewater, the present invention mixes the electrolytic wastewater with an adsorbent, performs adsorption treatment, and then filters to obtain purified water.

[0039] In terms of weight, the adsorbent of the present invention includes 8 to 12 parts of bentonite. As an embodiment, the amount of the bentonite can be specifically 8 parts, 9 parts, 10 parts, 11 parts or 12 parts. In the present invention, the bentonite has a large specific surface area and ion exchange performance, can adsorb heavy metal ions, and can have a synergistic effect with other substances to improve the removal rate of heavy metals.

[0040] In the present invention, the bentonite is preferably sodium bentonite; the particle size of the bentonite is preferably 50 to 75 μm. The present invention controls the amount and particle size of the bentonite within the above range, which can further improve the removal rate of heavy metal ions in wastewater.

[0041] The present invention has no special limitation on the source of the bentonite, and commercial products known to those skilled in the art can be used. In the embodiment of the present invention, the bentonite is purchased from Xinyang Genyuan Industrial Co., Ltd.

[0042] Based on 8 to 12 parts of bentonite, the adsorbent of the present invention further includes 2 to 5 parts of chitosan. As an embodiment, the amount of chitosan can be specifically 2 parts, 3 parts, 4 parts or 5 parts. In the present invention, the chitosan contains a large number of active groups such as amino and hydroxyl groups, which can react with heavy metal ions by chelation, and can have a synergistic effect with other substances to improve the removal rate of heavy metals.

[0043] In the present invention, the particle size of the chitosan is preferably 20 to 200 meshes. The present invention controls the dosage and particle size of the chitosan within the above range, which can further improve the removal rate of heavy metal ions in wastewater.

[0044] The present invention has no particular limitation on the source of the chitosan, and commercial products known to those skilled in the art can be used. In the embodiment of the present invention, the chitosan is industrial grade chitosan produced by Wuhan Jiyesheng Chemical Co., Ltd.

[0045] Based on 8 to 12 parts of bentonite, the adsorbent of the present invention also includes 9 to 13 parts of polyaluminium chloride. As an embodiment, the amount of the polyaluminium chloride can be specifically 9 parts, 10 parts, 11 parts, 12 parts or 13 parts. In the present invention, the polyaluminium chloride is used as a flocculant to promote the precipitation of heavy metal ions, and can have a synergistic effect with other substances to improve the removal rate of heavy metals. The present invention controls the amount of polyaluminium chloride within the above range, which can further improve the removal rate of heavy metal ions in wastewater.

[0046] The present invention has no particular limitation on the source of the polyaluminium chloride, and commercially available products known to those skilled in the art can be used. In an embodiment of the present invention, the polyaluminium chloride is an industrial grade polyaluminium chloride produced by Wuhan Jiyesheng Chemical Co., Ltd.

[0047] Based on 8 to 12 parts of bentonite, the adsorbent of the present invention further includes 5 to 9 parts of fly ash. As an embodiment, the amount of fly ash can be specifically 5 parts, 6 parts, 7 parts, 8 parts or 9 parts. In the present invention, the fly ash has a porous structure and can also play a certain adsorption role on heavy metal ions. At the same time, it can have a synergistic effect with other substances to improve the removal rate of heavy metals.

[0048] In the present invention, the particle size of the fly ash is preferably 10 to 100 meshes. The present invention controls the amount and particle size of the fly ash within the above range, which can further improve the removal rate of heavy metal ions in wastewater.

[0049] The present invention has no particular limitation on the source of the fly ash, and commercial products known to those skilled in the art can be used. In an embodiment of the present invention, the fly ash is secondary fly ash produced by Guodian Datong Power Generation Co., Ltd.

[0050] The present invention has no special limitation on the preparation method of the adsorbent, as long as the components can be mixed evenly.

[0051] In the present invention, the mass ratio of the adsorbent to the volume of the electrolytic wastewater is preferably (0.1-5) g: 1 L. As an embodiment, the mass ratio of the adsorbent to the volume of the electrolytic wastewater can be specifically 0.1 g: 1 L, 0.5 g: 1 L, 1 g: 1 L, 1.5 g: 1 L, 2 g: 1 L, 3 g: 1 L, 4 g: 1 L or 5 g: 1 L.

[0052] In the present invention, the temperature of the adsorption treatment is preferably 10 to 30° C. As an embodiment, the temperature of the adsorption treatment may be specifically 10° C., 15° C., 20° C., 25° C. or 30° C.

[0053] In the present invention, the time of the adsorption treatment is preferably 20 to 30 minutes. As an embodiment, the time of the adsorption treatment may be specifically 20 minutes, 25 minutes or 30 minutes. In the present invention, the adsorption treatment is preferably carried out under stirring conditions. The present invention has no special restrictions on the stirring method and rate, and the stirring technical scheme familiar to those skilled in the art can be adopted. The present invention controls the amount of adsorbent, the temperature and time of the adsorption treatment within the above range, which can further improve the removal rate of heavy metal ions in wastewater.

[0054] After the adsorption treatment is completed, the present invention preferably allows the product of the adsorption treatment to stand and then filter to obtain purified water.

[0055] In the present invention, the standing time is preferably 0.5 to 2 hours.

[0056] The present invention has no special limitation on the filtering operation, and the technical solutions well known to those skilled in the art can be adopted.

[0057] The invention first filters the wastewater, then performs iron-carbon micro-electrolysis, and then performs adsorption, controls various process parameters in the treatment process, and improves the removal rate of heavy metal ions in the heavy metal-containing wastewater.

[0058] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Example 1

[0060] A method for treating heavy metal-containing wastewater: (1) filtering heavy metal-containing wastewater (wastewater containing copper, lead and nickel, with a lead ion concentration of 58 mg / L, a copper ion concentration of 75 mg / L, a nickel ion concentration of 49 mg / L, and a pH value of 5) to obtain filtered wastewater;

[0061] (2) subjecting the filtered wastewater to iron-carbon micro-electrolysis, wherein the temperature of the iron-carbon micro-electrolysis is 40° C., the time of the iron-carbon micro-electrolysis is 30 min, the iron-carbon mass ratio in the iron-carbon micro-electrolysis filler is 6:1, the particle size of the iron-carbon micro-electrolysis filler is 2 to 6 mm, and air is introduced during the iron-carbon micro-electrolysis process, and the volume ratio of air to water is 3:1, thereby obtaining electrolyzed wastewater;

[0062] (3) The electrolytic wastewater is mixed with an adsorbent, subjected to adsorption treatment, and filtered after standing for 1 hour to obtain purified water; the adsorbent is composed of the following components by weight: 8 parts of sodium bentonite (particle size 50-75 μm, Xinyang Genyuan Industrial Co., Ltd.), 2 parts of chitosan (20-200 mesh, industrial-grade chitosan produced by Wuhan Jiyesheng Chemical Co., Ltd.), 9 parts of polyaluminum chloride (industrial-grade polyaluminum chloride produced by Wuhan Jiyesheng Chemical Co., Ltd.) and 5 parts of fly ash (10-100 mesh, secondary fly ash produced by Guodian Power Datong Power Generation Co., Ltd.); the mass ratio of the adsorbent to the volume of the electrolytic wastewater is 1 g:1 L, the temperature of the adsorption treatment is 25°C, and the time of the adsorption treatment is 30 min.

[0063] Example 2

[0064] The composition of the adsorbent in Example 1 was replaced by: 10 parts of sodium bentonite, 3 parts of chitosan, 11 parts of polyaluminium chloride and 7 parts of fly ash; the other parameters were the same as those in Example 1.

[0065] Example 3

[0066] The composition of the adsorbent in Example 1 was replaced by: 12 parts of sodium bentonite, 3 parts of chitosan, 11 parts of polyaluminium chloride and 9 parts of fly ash; the other parameters were the same as those in Example 1.

[0067] Embodiments 4 to 7

[0068] The pH values ​​of the heavy metal-containing wastewater in Example 3 were replaced with 3, 4, 6 and 7 respectively, and the other parameters were the same as those in Example 3.

[0069] Embodiments 8 to 10

[0070] The temperatures of the iron-carbon micro-electrolysis in Example 3 were replaced with 30°C, 50°C and 60°C respectively, and the other parameters were the same as those in Example 3.

[0071] Examples 11 to 13

[0072] The iron-carbon mass ratios in the iron-carbon micro-electrolysis filler in Example 3 were replaced with 4:1, 5:1 and 7:1 respectively, and the other parameters were the same as those in Example 3.

[0073] Embodiments 14 to 16

[0074] The mass ratio of the adsorbent to the volume of the electrolyzed wastewater in Example 3 was replaced with 0.5 g:1 L, 2 g:1 L and 3 g:1 L, respectively, and the other parameters were the same as those in Example 3.

[0075] Comparative Example 1

[0076] The fly ash in the adsorbent of Example 3 was omitted, the amount of sodium bentonite was changed to 21 parts, and the other parameters were the same as those of Example 3.

[0077] Comparative Example 2

[0078] The polyaluminium chloride in the adsorbent of Example 3 was omitted, the amount of sodium bentonite was changed to 23 parts, and the other parameters were the same as those of Example 3.

[0079] Comparative Example 3

[0080] The chitosan in the adsorbent of Example 3 was omitted, the amount of sodium bentonite was changed to 15 parts, and the other parameters were the same as those of Example 3.

[0081] Comparative Example 4

[0082] The sodium bentonite in the adsorbent of Example 3 was omitted, the amount of polyaluminium chloride was changed to 23 parts, and the other parameters were the same as those of Example 3.

[0083] Comparative Example 5

[0084] The polyaluminium chloride in the adsorbent of Example 3 was replaced by polyacrylamide, and the other parameters were the same as those of Example 3.

[0085] Comparative Example 6

[0086] Step (2) in Example 3 was omitted, and other parameters were the same as those in Example 3.

[0087] The removal rates of heavy metals in heavy metal-containing wastewaters in Examples 1 to 3 and Comparative Examples 1 to 6 are as follows: Figure 1 And as shown in Table 1.

[0088] Table 1 Removal rate of heavy metals in heavy metal-containing wastewater of Examples 1 to 3 and Comparative Examples 1 to 6

[0089]

[0090] The removal rates of heavy metals in the heavy metal-containing wastewater of Examples 3 and 4 to 7 are shown in Table 2.

[0091] Table 2 Removal rate of heavy metals in heavy metal-containing wastewater in Examples 3 and 4 to 7

[0092]

[0093] The removal rates of heavy metals in heavy metal-containing wastewaters of Examples 3 and 8 to 10 are shown in Table 3.

[0094] Table 3 Removal rate of heavy metals in heavy metal-containing wastewater of Examples 3 and 8 to 10

[0095]

[0096] The removal rates of heavy metals in heavy metal-containing wastewaters of Examples 3 and 11 to 13 are shown in Table 4.

[0097] Table 4 Removal rate of heavy metals in heavy metal-containing wastewater in Examples 3 and 11 to 13

[0098]

[0099] The removal rates of heavy metals in heavy metal-containing wastewaters of Examples 3 and 14 to 13 are shown in Table 5.

[0100] Table 5 Removal rate of heavy metals in heavy metal-containing wastewater of Examples 3 and 14 to 16

[0101]

[0102] It can be seen from Tables 1 to 5 that under the same treatment conditions, when the total amount of adsorbent is the same, adding sodium bentonite, chitosan, polyaluminium chloride and fly ash at the same time has a better heavy metal ion removal rate than adding only three of them or replacing one of them with other substances, which proves that sodium bentonite, chitosan, polyaluminium chloride and fly ash have a synergistic effect and can further improve the removal rate of heavy metals; adding the iron-carbon micro-electrolysis step can further improve the removal rate of heavy metal ions, because iron-carbon micro-electrolysis can destroy the binding form of heavy metal ions in wastewater, which is more conducive to the subsequent adsorption process; each parameter in the treatment process has a certain influence on the removal effect of heavy metal ions.

[0103] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for treating heavy metal-containing wastewater, comprising the following steps: (1) filtering the heavy metal-containing wastewater to obtain filtered wastewater; (2) subjecting the filtered wastewater obtained in step (1) to iron-carbon micro-electrolysis to obtain electrolyzed wastewater; (3) mixing the electrolytic wastewater obtained in step (2) with an adsorbent, subjecting the mixture to adsorption treatment and then filtering the mixture to obtain purified water; The adsorbent comprises the following components by weight: 8 to 12 parts of bentonite, 2 to 5 parts of chitosan, 9 to 13 parts of polyaluminium chloride and 5 to 9 parts of fly ash.

2. The processing method according to claim 1, characterized in that: The pH value of the heavy metal-containing wastewater in step (1) is 3-7.

3. The processing method according to claim 1, characterized in that: The heavy metal ions in the heavy metal-containing wastewater in step (1) include one or more of lead ions, copper ions and nickel ions; the concentrations of lead ions, copper ions and nickel ions in the heavy metal-containing wastewater are independently 15 to 100 mg / L.

4. The processing method according to claim 1, characterized in that: In the step (2), the temperature of the iron-carbon micro-electrolysis is 30-60° C., the time of the iron-carbon micro-electrolysis is 20-40 min, the iron-carbon mass ratio in the iron-carbon micro-electrolysis filler is 1-10:1, and the particle size of the iron-carbon micro-electrolysis filler is 1-30 mm.

5. The processing method according to claim 4, characterized in that: In the step (2), air is introduced during the iron-carbon micro-electrolysis process; the volume ratio of air to water is 3 to 6:

1.

6. The processing method according to claim 1, characterized in that: The bentonite in step (3) is sodium-based bentonite; the particle size of the bentonite is 50 to 75 μm.

7. The processing method according to claim 1, characterized in that: The particle size of chitosan in step (3) is 20-200 meshes.

8. The processing method according to claim 1, characterized in that: The particle size of the fly ash in step (3) is 10 to 100 meshes.

9. The processing method according to claim 1, characterized in that: In the step (3), the ratio of the mass of the adsorbent to the volume of the electrolytic wastewater is (0.1-5) g:1L.

10. The processing method according to claim 1, characterized in that: The temperature of the adsorption treatment in step (3) is 10 to 30° C., and the time of the adsorption treatment is 20 to 30 minutes.

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