Method for removing heavy metal ions in aluminum-containing wastewater

Abstract

The invention discloses a method for removing heavy metal ions in aluminum-containing wastewater, and relates to the technical field of wastewater treatment. The method for removing the heavy metal ions in the aluminum-containing wastewater comprises the following steps: S1, filtering and removing impurities: removing large-particle insoluble substances in the wastewater through a filter to obtain a primary filtrate; s2, the pH of the primary filtrate is adjusted to 2-5, the primary filtrate passes through an ion exchange column filled with chelating resin at the speed of 1-15 BV / h, BV is the volume of the chelating resin, heavy metal ions are adsorbed by the ion exchange resin, and aluminum-containing filtrate flows out; s3, the aluminum-containing filtrate is subjected to nanofiltration and reverse osmosis two-stage filtration treatment, and treated waste liquid is obtained. According to the method, the heavy metal ions in the aluminum-containing wastewater are efficiently removed, the removal rate of the heavy metal ions is 90% or above, the chromaticity of the wastewater can be effectively reduced, the chromaticity value of the treated wastewater is 15 or below, and the method can be widely applied to heavy metal ion removal and chromaticity reduction of the aluminum profile wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and more specifically, to a method for removing heavy metal ions from aluminum-containing wastewater. Background Art

[0002] With the rapid development of the aluminum profile industry, China has become a major manufacturing country of aluminum profiles. The aluminum profile products need to be surface-treated, and the main processes include degreasing, alkali etching, pickling, oxidation, coloring, and sealing holes, etc. A large amount of aluminum-containing wastewater is generated after each process. The wastewater mainly contains a large amount of aluminum ions, and also contains some metal ions such as chromium, nickel, and copper. After the wastewater is treated, a large amount of aluminum profile sludge containing heavy metals is produced. Since the wastewater from aluminum profile factories contains colored inorganic heavy metal ions, the subsequent products prepared from the sludge are difficult to meet the requirements of the chromaticity of high-quality resource utilization products. Therefore, there is an urgent need for a method for removing heavy metal ions from aluminum profile wastewater, which can effectively and fully perform deep chromium removal and nickel removal on the treated wastewater of aluminum profiles, so as to meet the requirements of the high-quality aluminum profile sludge market. The wastewater from aluminum profile processing contains relatively more heavy metal ions such as nickel, chromium, and copper. The heavy metal-containing wastewater is a type of pollutant, but at the same time, heavy metals such as nickel, chromium, and copper are also valuable metal resources and have important application scenarios. Therefore, it is of great significance to recover heavy metals for reuse while treating sewage.

[0003] The prior art discloses a method for biological adsorption and recovery of heavy metals in industrial wastewater, which is used to treat industrial wastewater with a chromium, nickel, copper, silver, and molybdenum content of less than 2 mg / L and a pH < 2. The specific method is as follows: Take the industrial wastewater containing heavy metal ions and mix it with the Pichia kudriavzevii biological adsorbent. By controlling the adsorption conditions, perform shaking adsorption treatment, centrifuge and filter to collect the supernatant, perform adsorption treatment again, centrifuge and filter, and detect the metal ion concentration in the supernatant; the heavy metal ions are chromium ions, nickel ions, copper ions, silver ions, and molybdenum ions; the Pichia kudriavzevii biological adsorbent is obtained by enriching and culturing Pichia kudriavzevii under high acidity conditions, centrifuging to collect the thalli, then adding 0.1 mol / L NaOH solution for pretreatment, boiling, and then centrifuging, drying, and grinding into powder. This method only treats low-concentration heavy metal industrial wastewater with a content of less than 2 mg / L, and the subsequent heavy metal recovery is difficult by adsorbing heavy metals with a biological adsorbent, and the problem of improving chromaticity is not solved at the same time. Summary of the Invention

[0004] The object of the present invention is to overcome the defects and deficiencies that the existing industrial wastewater with high heavy metal content cannot simultaneously achieve deep heavy metal removal and recovery and chromaticity requirements, and to provide a method for removing heavy metal ions from wastewater. Through the synergistic effect of the overall special treatment process, the high-content heavy metals in the industrial wastewater are significantly and effectively recovered, and the chromaticity of the industrial wastewater is significantly reduced to meet the chromaticity requirements of the product.

[0005] The above object of the present invention is achieved by the following technical solutions:

[0006] A method for removing heavy metal ions from aluminum-containing wastewater, comprising the following steps:

[0007] S1. Filtration and impurity removal: Pass the wastewater through a filter to remove large particulate insoluble substances in the wastewater, and obtain a primary filtrate;

[0008] S2. Adjust the pH of the primary filtrate to 2-5, and pass it through an ion exchange column filled with chelating resin at a rate of 1-15 BV / h, where BV is the volume of the chelating resin. The heavy metal ions are adsorbed by the ion exchange resin, and the aluminum-containing filtrate flows out;

[0009] S3. Subject the aluminum-containing filtrate to two-stage filtration treatment of nanofiltration and reverse osmosis to obtain the treated waste liquid,

[0010] where the nanofiltration pressure is 0.5-2 Mpa and the reverse osmosis pressure is 1-2 Mpa.

[0011] Among them, it should be noted that:

[0012] The aluminum profile wastewater contains a large amount of aluminum, and aluminum is amphoteric in solution. Adjusting the pH value of the primary filtrate can control the main existence form of aluminum as [Al(H2O)6] 3+ , which is more conducive to subsequent chelation and two-stage filtration treatment.

[0013] Chelating resin mainly removes heavy metals by replacing metal ions in water. The atoms on the functional groups of the chelating resin coordinate with metal ions to produce coordination covalent bonds, and more stably adsorb metal ions. The flow rate is controlled at 1-15 BV / h. If the adsorption flow rate is too large, the contact is insufficient, the resin adsorption is insufficient, and the adsorption capacity of the resin decreases. If the adsorption flow rate is too slow, the residence time of the solution in the resin mass transfer will increase, and the adsorption time will increase.

[0014] Nanofiltration is a membrane separation process between reverse osmosis and ultrafiltration driven by transmembrane pressure difference, with a higher rejection rate for ions with a valence of two or more. Reverse osmosis is a higher-level separation technology. The present invention combines chelating resin with NF-RO two-stage membrane cascade technology, controls the nanofiltration pressure and reverse osmosis pressure in S3 to act synergistically, more efficiently separates heavy metal ions, realizes heavy metal removal and meets the chromaticity requirements of the product.

[0015] The method for removing heavy metal ions from aluminum-containing wastewater in the present invention effectively separates heavy metal ions from aluminum in the aluminum-containing wastewater by controlling specific chelating resin ion adsorption process conditions and combining two-stage filtration treatment of nanofiltration and reverse osmosis, obtaining treated wastewater containing aluminum sludge, in which heavy metal ions are effectively removed through chelating resin ion adsorption treatment and two-stage filtration treatment of nanofiltration and reverse osmosis.

[0016] In the present invention, the content of heavy metal ions in the wastewater before and after treatment can be determined by inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0017] The chromaticity of the wastewater solution before and after treatment is determined by platinum-cobalt visual colorimetry.

[0018] In the method for removing heavy metal ions from aluminum-containing wastewater in the present invention, the pH value can be adjusted by adding a 30-32 wt% sodium hydroxide solution or a 30-32 wt% hydrochloric acid solution.

[0019] In a specific embodiment, in order to improve the interception effect of heavy metals, preferably, the nanofiltration pressure in S3 is 1.8-2 Mpa.

[0020] A high operating pressure will cause pollutants in the wastewater to more easily adhere to the membrane surface, form a pollution layer, increase the membrane resistance, reduce the water permeability and increase the energy consumption. If the pressure is too low, the membrane interception rate of the wastewater is low.

[0021] In a specific embodiment, in order to improve the interception effect of heavy metals, preferably, the osmotic pressure in S3 is 1-1.5 Mpa.

[0022] In a specific embodiment, preferably, the pH of the filtered wastewater in S3 is adjusted to 7-7.5, and a flocculant is added for precipitation, and solid-liquid separation is carried out to obtain aluminum-containing sludge and treated wastewater.

[0023] Among them, in step S3, by adjusting the pH value of the filtered wastewater, the aluminum ions present in the filtrate can be adjusted to the form of Al(OH)3, a flocculant, such as flocculant PAM, is added, and after precipitation, the solid-liquid separation product is further added to a filter press for dehydration treatment, and aluminum profile sludge can be obtained, effectively recovering the aluminum ions therein.

[0024] Preferably, the initial filtrate in S2 passes through an ion exchange column filled with chelating resin at a rate of 1-15 BV / h.

[0025] In a specific embodiment, the ion exchange resin in S2 of the present invention can be regenerated by adding a 10% hydrochloric acid solution and a 10% sodium hydroxide solution at a rate of 0.5-2 BV / h, where BV is the volume of the chelating resin.

[0026] When the chelating resin fails during use and loses its adsorption effect on heavy metal ions, it needs to be regenerated. In the regeneration operation, hydrochloric acid solution and sodium hydroxide solution are used to regenerate and restore the chelating resin that has lost its adsorption effect.

[0027] In a specific embodiment, the chelating resin of the present invention can be any one of D401, D402, and D421.

[0028] The functional functional groups on the chelating resin can undergo a coordination reaction with heavy metal cations to form stable chelates, effectively removing heavy metal ions in wastewater.

[0029] The method for removing heavy metal ions from aluminum-containing wastewater of the present invention is applicable to the removal of heavy metal ions in various aluminum-containing industrial wastewaters, especially applicable to the removal of one or more heavy metals including nickel, copper, or chromium.

[0030] Similarly, the method for removing heavy metal ions from aluminum-containing wastewater of the present invention is applicable to the removal of heavy metal ions in various aluminum-containing industrial wastewaters, especially can effectively solve the recycling and regeneration of heavy metals in industrial wastewaters with high-concentration heavy metal ions. Among them, the content of nickel in the wastewater is ≤ 100 mg / L, the content of copper is ≤ 500 mg / L, and the content of chromium is ≤ 500 mg / L.

[0031] More preferably, the content of nickel in the wastewater is 20 - 100 mg / L, the content of copper is 300 - 500 mg / L, and the content of chromium is 300 - 500 mg / L.

[0032] The method for removing heavy metal ions from aluminum-containing wastewater of the present invention can effectively reduce the chromaticity of industrial wastewater while efficiently recovering various high-concentration heavy metal ions in aluminum-containing wastewater. Especially for treating industrial wastewater with high chromaticity, the chromaticity of the wastewater is greater than or equal to 200.

[0033] The aluminum-containing wastewater of the present invention can be, for example, aluminum profile wastewater. By the method for removing heavy metal ions from aluminum-containing wastewater of the present invention, not only can various high-concentration heavy metal ions in aluminum profile wastewater be effectively recovered, the chromaticity of aluminum profile wastewater be significantly reduced, but also the aluminum ions in aluminum profile wastewater can be separated and recovered to obtain aluminum profile sludge of Al(OH)3.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] The method for removing heavy metal ions from aluminum-containing wastewater of the present invention realizes the efficient removal of heavy metal ions in aluminum-containing wastewater through a specific chelating resin ion adsorption process combined with two-stage filtration treatment of nanofiltration and reverse osmosis. The removal rate of heavy metal ions is above 90%, and the chromaticity of the wastewater can be effectively reduced. The chromaticity value of the treated wastewater is 15 or below, and it can be widely applied to the removal of heavy metal ions and the reduction of chromaticity in aluminum profile wastewater. Detailed implementation manners

[0036] The present invention will be further described below in conjunction with specific implementation manners, but the embodiments do not impose any form of limitation on the present invention. Unless otherwise specified, the raw material reagents used in the embodiments of the present invention are conventionally purchased raw material reagents.

[0037] Example 1

[0038] A method for removing heavy metal ions from aluminum-containing wastewater, characterized by comprising the following steps:

[0039] S1. Filtration and impurity removal: The wastewater is passed through a filter to remove large particulate insoluble substances in the wastewater, and a primary filtrate is obtained;

[0040] S2. Adjust the pH of the aluminum profile wastewater containing heavy metals to 2, and pass it through an ion exchange column filled with D401 chelating resin at a rate of 2 BV / h. The heavy metal ions are adsorbed by the ion exchange resin, and the aluminum-containing filtrate flows out;

[0041] The resin with adsorption breakthrough is added with a 10 wt% hydrochloric acid solution and a 10 wt% sodium hydroxide solution as an eluent at a rate of 1 BV / h to regenerate the resin.

[0042] S3. When the aluminum-containing filtrate collected after resin adsorption is subjected to nanofiltration, the pressure is controlled at 1.8 Mpa, and when subjected to reverse osmosis, the pressure is controlled at 1 Mpa. After passing through the two-stage filtration treatment equipment of nanofiltration and reverse osmosis, the content of heavy metal ions in the wastewater is reduced to obtain the treated aluminum profile wastewater that meets the standards.

[0043] Since the aluminum profile wastewater obtained in step S3 contains a large amount of aluminum, the pH of the aluminum profile wastewater in S4 is adjusted to 7 - 7.5, passed into a sedimentation tank, and then a flocculant PAM is added. A solid-liquid separation product is obtained in the sedimentation tank, and the sediment is further added to a filter press for dehydration treatment to obtain aluminum profile sludge.

[0044] The content of heavy metal ions in the aluminum profile wastewater before and after treatment is measured by inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine the removal effect. The chromaticity of the aluminum profile wastewater solution before and after decolorization is measured by the platinum-cobalt visual colorimetry method.

[0045] Example 2

[0046] A method for removing heavy metal ions from aluminum-containing wastewater, characterized by comprising the following steps:

[0047] S1. Filtration and impurity removal: Pass the wastewater through a filter to remove large particulate insoluble substances in the wastewater, and obtain a primary filtrate;

[0048] S2. Adjust the pH of the aluminum profile wastewater containing heavy metals to 3, and pass it through an ion exchange column filled with D401 chelating resin at a rate of 3 BV / h. The heavy metal ions are adsorbed by the ion exchange resin, and the aluminum-containing filtrate flows out;

[0049] The resin with adsorption breakthrough is added with 10 wt% hydrochloric acid solution and 10 wt% sodium hydroxide solution as an eluent at a rate of 1.5 BV / h to regenerate the resin.

[0050] S3. When nanofiltration is carried out on the aluminum-containing filtrate collected after resin adsorption, the pressure is controlled at 1.9 Mpa, and when reverse osmosis is carried out, the pressure is controlled at 1.5 Mpa. After passing through a two-stage filtration treatment device of nanofiltration and reverse osmosis, the content of heavy metal ions in the wastewater is reduced, and the treated aluminum profile wastewater meeting the indexes is obtained.

[0051] Since the aluminum profile wastewater obtained in step S3 contains a large amount of aluminum, the pH of the aluminum profile wastewater in S3 is adjusted to 7-7.5, passed into a sedimentation tank, and then a flocculant PAM is added. A solid-liquid separation product is obtained in the sedimentation tank, and the precipitate is further added to a filter press for dehydration treatment to obtain aluminum profile sludge.

[0052] The content of heavy metal ions in the aluminum profile wastewater before and after treatment is measured by inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine the removal effect. The chromaticity of the aluminum profile wastewater solution before and after decolorization is determined by platinum-cobalt visual colorimetry.

[0053] Example 3

[0054] A method for removing heavy metal ions from aluminum-containing wastewater, characterized by comprising the following steps:

[0055] S1. Filtration and impurity removal: Pass the wastewater through a filter to remove large particulate insoluble substances in the wastewater, and obtain a primary filtrate;

[0056] S2. Adjust the pH of the aluminum profile wastewater containing heavy metals to 4, and pass it through an ion exchange column filled with D401 chelating resin at a rate of 5 BV / h. The heavy metal ions are adsorbed by the ion exchange resin, and the aluminum-containing filtrate flows out;

[0057] The resin with adsorption breakthrough is added with 10% hydrochloric acid solution and 10% sodium hydroxide solution as an eluent at a rate of 2 BV / h to regenerate the resin.

[0058] S3. When nanofiltering the aluminum-containing filtrate collected after resin adsorption, the pressure is controlled at 2 Mpa, and when reverse osmosis is carried out, the pressure is controlled at 2 Mpa. Through the two-stage filtration treatment equipment of nanofiltration and reverse osmosis, the content of heavy metal ions in the wastewater is reduced, and the treated aluminum profile wastewater meeting the index is obtained.

[0059] Since the aluminum profile wastewater obtained in step S3 contains a large amount of aluminum, the pH of the aluminum profile wastewater in S3 is adjusted to 7 - 7.5, it is introduced into a sedimentation tank and then a flocculant PAM is added. A solid-liquid separation product is obtained in the sedimentation tank, and the sediment is further added to a filter press for dehydration treatment to obtain aluminum profile sludge.

[0060] The inductively coupled plasma atomic emission spectrometry (ICP-AES) is used to measure the content of heavy metal ions in the aluminum profile wastewater before and after treatment to determine the removal effect. The chromaticity of the aluminum profile wastewater solution before and after decolorization is measured by the platinum-cobalt visual colorimetry method.

[0061] Example 4

[0062] A method for removing heavy metal ions from aluminum-containing wastewater, characterized by comprising the following steps:

[0063] S1. Filtration and impurity removal: The wastewater is passed through a filter to remove large particulate insoluble substances in the wastewater, and a primary filtrate is obtained;

[0064] S2. Adjust the pH of the aluminum profile wastewater containing heavy metals to 2, and pass it through an ion exchange column filled with D401 chelating resin at a rate of 2 BV / h. The heavy metal ions are adsorbed by the ion exchange resin, and the aluminum-containing filtrate flows out;

[0065] The resin with adsorption breakthrough is added with 10% hydrochloric acid solution and 10% sodium hydroxide solution as eluents at a rate of 2 BV / h to regenerate the resin.

[0066] S3. When nanofiltering the aluminum-containing filtrate collected after resin adsorption, the pressure is controlled at 1 Mpa, and when reverse osmosis is carried out, the pressure is controlled at 1 Mpa. Through the two-stage filtration treatment equipment of nanofiltration and reverse osmosis, the content of heavy metal ions in the wastewater is reduced, and the treated aluminum profile wastewater meeting the index is obtained.

[0067] Since the aluminum profile wastewater obtained in step S3 contains a large amount of aluminum, the pH of the aluminum profile wastewater in S3 is adjusted to 7 - 7.5, it is introduced into a sedimentation tank and then a flocculant PAM is added. A solid-liquid separation product is obtained in the sedimentation tank, and the sediment is further added to a filter press for dehydration treatment to obtain aluminum profile sludge.

[0068] The inductively coupled plasma atomic emission spectrometry (ICP-AES) is used to measure the content of heavy metal ions in the aluminum profile wastewater before and after treatment to determine the removal effect. The chromaticity of the aluminum profile wastewater solution before and after decolorization is measured by the platinum-cobalt visual colorimetry method.

[0069] Comparative Example 1

[0070] A method for removing heavy metal ions from aluminum-containing wastewater, characterized by comprising the following steps:

[0071] S1. Filtration and impurity removal: Pass the wastewater through a filter to remove large particulate insoluble substances in the wastewater, obtaining a primary filtrate;

[0072] S2. Adjust the pH of the aluminum profile wastewater containing heavy metals to 7, and pass it through an ion exchange column filled with D401 chelating resin at a rate of 2 BV / h. The heavy metal ions are adsorbed by the ion exchange resin, and the aluminum-containing filtrate flows out;

[0073] The resin with adsorption breakthrough is added with 10 wt% hydrochloric acid solution and 10 wt% sodium hydroxide solution as an eluent at a rate of 1 BV / h to regenerate the resin,

[0074] S3. When nanofiltration of the aluminum-containing filtrate collected after resin adsorption, the pressure is controlled at 1.8 Mpa, and when reverse osmosis, the pressure is controlled at 1 Mpa. Through a two-stage filtration treatment device of nanofiltration and reverse osmosis, the content of heavy metal ions in the wastewater is reduced to obtain treated aluminum profile wastewater meeting the standards.

[0075] Since the aluminum profile wastewater obtained in step S3 contains a large amount of aluminum, adjust the pH of the aluminum profile wastewater in S4 to 7 - 7.5, pass it into a sedimentation tank and then add the flocculant PAM. A solid-liquid separation product is obtained in the sedimentation tank, and the precipitate is further added to a filter press for dehydration treatment to obtain aluminum profile sludge.

[0076] The content of heavy metal ions in the aluminum profile wastewater before and after treatment is determined by inductively coupled plasma atomic emission spectrometry (ICP - AES) to determine the removal effect. The chromaticity of the aluminum profile wastewater solution before and after decolorization is determined by the platinum-cobalt visual colorimetric method.

[0077] Comparative Example 2

[0078] A method for removing heavy metal ions from aluminum-containing wastewater, characterized by comprising the following steps:

[0079] S1. Filtration and impurity removal: Pass the wastewater through a filter to remove large particulate insoluble substances in the wastewater, obtaining a primary filtrate;

[0080] S2. Adjust the pH of the aluminum profile wastewater containing heavy metals to 2, and pass it through an ion exchange column filled with D401 chelating resin at a rate of 2 BV / h. The heavy metal ions are adsorbed by the ion exchange resin, and the aluminum-containing filtrate flows out;

[0081] The resin with adsorption breakthrough is added with 10 wt% hydrochloric acid solution and 10 wt% sodium hydroxide solution as an eluent at a rate of 1 BV / h to regenerate the resin,

[0082] S3. When nanofiltering the aluminum-containing filtrate collected after resin adsorption, the pressure is controlled at 2.5 Mpa, and when reverse osmosis is carried out, the pressure is controlled at 1 Mpa. Through the two-stage filtration treatment equipment of nanofiltering and reverse osmosis, the heavy metal ion content in the wastewater is reduced to obtain the treated aluminum profile wastewater that meets the indicators.

[0083] Since the aluminum profile wastewater obtained in step S3 contains a large amount of aluminum, the pH of the aluminum profile wastewater in S4 is adjusted to 7 - 7.5, then it is introduced into the sedimentation tank and the flocculant PAM is added. The solid-liquid separation product is obtained in the sedimentation tank, and the sediment is further dehydrated by a filter press to obtain aluminum profile sludge.

[0084] The inductively coupled plasma atomic emission spectrometry (ICP-AES) is used to determine the heavy metal ion content of the aluminum profile wastewater before and after treatment to determine the removal effect. The chromaticity of the aluminum profile wastewater solution before and after decolorization is determined by the platinum-cobalt visual colorimetry method.

[0085] Result detection

[0086] The aluminum profile wastewater obtained by the treatment methods of Examples 1 - 4 and the aluminum profile wastewater obtained by the treatment methods of Comparative Examples 1 - 2 are detected, and the results are shown in Table 1 below.

[0087] Table 1

[0088]

[0089] It can be seen from Table 1 above that the method for removing heavy metal ions from aluminum-containing wastewater of the present invention effectively separates heavy metal ions from aluminum in the aluminum-containing wastewater by controlling specific chelating resin ion adsorption process conditions and combining two-stage filtration treatment of nanofiltering and reverse osmosis. Through treatment, the contents of nickel, copper, and chromium in the aluminum profile wastewater are all reduced to relatively low values. Among them, the nickel content is reduced from the original 28.30 mg / L to 4.33 mg / L or less, and the lowest can reach 2.14 mg / L; the copper content is reduced from the original 329.35 mg / L to 36.39 mg / L or less, and the lowest can reach 30.92 mg / L; the chromium content is reduced from the original 300.89 mg / L to 35.78 mg / L or less, and the lowest can reach 28.12 mg / L, effectively achieving the removal of multiple heavy metal ions in the aluminum profile wastewater, and at the same time controlling the wastewater chromaticity at 15.

[0090] In Comparative Example 1, the pH value of the initial filtrate was not adjusted to the protection range of the present invention after the filtration and impurity removal treatment, and the pH value was too high, which affected the ion exchange effect of the subsequent chelating resin and the two-stage filtration treatment effect of nanofiltering and reverse osmosis. The final contents of nickel, copper, and chromium could not reach the treatment effect of the present invention.

[0091] The conditions of the two-stage filtration of nanofiltration and reverse osmosis in Comparative Example 2 are controlled within the protection scope of the present invention, which also directly affects the removal effect of heavy metal ions in the aluminum profile wastewater. The final contents of nickel, copper and chromium cannot be reduced to achieve the treatment effect of the present invention either.

[0092] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or alterations can be made on the basis of the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A method for removing heavy metal ions from aluminum-containing wastewater, characterized in that, It includes the following steps: S1. Filtration and impurity removal: Pass the wastewater through a filter to remove insoluble substances in the wastewater, and obtain a primary filtrate; S2. Adjust the pH of the primary filtrate to 2 - 5, and pass it through an ion exchange column filled with chelating resin at a rate of 1 - 15 BV / h, where BV is the volume of the chelating resin, to obtain an aluminum-containing filtrate; S3. Subject the aluminum-containing filtrate to two-stage filtration treatment of nanofiltration and reverse osmosis to obtain the treated waste liquid, where the nanofiltration pressure is 0.5 - 2 Mpa and the reverse osmosis pressure is 1 - 2 Mpa.

2. The method for removing heavy metal ions from aluminum-containing wastewater according to claim 1, characterized in that, In S3, the nanofiltration pressure is 1.8 - 2 Mpa.

3. The method for removing heavy metal ions from aluminum-containing wastewater according to claim 1, characterized in that In S3, the reverse osmosis pressure is 1 - 1.5 Mpa.

4. The method for removing heavy metal ions from aluminum-containing wastewater according to claim 1, characterized in that, In S2, the ion exchange resin is regenerated by adding a 5 - 15 wt% hydrochloric acid solution and a 5 - 15 wt% sodium hydroxide solution at a rate of 0.5 - 2 BV / h, where BV is the volume of the chelating resin.

5. The method for removing heavy metal ions from aluminum-containing wastewater according to claim 1, wherein The chelating resin is any one of D401, D402, and D421.

6. The method for removing heavy metal ions from aluminum-containing wastewater according to any one of claims 1 to 5, characterized in that, The heavy metal includes one or more of nickel, copper, or chromium.

7. The method for removing heavy metal ions from aluminum-containing wastewater according to claim 6, characterized in that, The content of nickel in the wastewater is ≤ 100 mg / L, the content of copper is ≤ 500 mg / L, and the content of chromium is ≤ 500 mg / L.

8. The method for removing heavy metal ions from aluminum-containing wastewater according to claim 7, characterized in that, The content of nickel in the wastewater is 20 - 100 mg / L, the content of copper is 300 - 500 mg / L, and the content of chromium is 300 - 500 mg / L.

9. The method for removing heavy metal ions from aluminum-containing wastewater according to any one of claims 1 to 5, characterized in that, The chromaticity of the wastewater is ≥ 200.

10. The method for removing heavy metal ions from aluminum-containing wastewater according to any one of claims 1 to 5, characterized in that, The wastewater is aluminum profile wastewater.

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