An edta-based wastewater treatment method

Abstract

The application discloses an EDTA-based wastewater treatment method, which comprises the following steps: pretreating wastewater; wherein the wastewater contains heavy metal ions; adding a prepared EDTA solution into the pretreated wastewater, stirring uniformly, and obtaining a mixed solution after a preset reaction time; adding a flocculating agent into the mixed solution, stirring uniformly, so that the heavy metal ions form a complex with the EDTA and are flocculated and precipitated, and obtaining precipitated wastewater; and performing solid-liquid separation on the precipitated wastewater to remove the complex precipitate of the heavy metal ions, and obtaining treated wastewater. The technical scheme of the application can effectively remove the heavy metal ions in the wastewater, and has the advantages of high efficiency and low cost.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a wastewater treatment method based on EDTA. Background Technology

[0002] Heavy metal ions in industrial wastewater pose serious threats to the environment and human health, making their removal essential. Traditional methods for heavy metal ion removal typically employ processes such as chemical precipitation or ion exchange; however, these methods suffer from low efficiency and high costs. Summary of the Invention

[0003] The purpose of this invention is to provide a wastewater treatment method based on EDTA, which can effectively remove heavy metal ions from wastewater and has the advantages of high efficiency and low cost.

[0004] To achieve the above objectives, embodiments of the present invention provide a wastewater treatment method based on EDTA, comprising:

[0005] Wastewater is pretreated; wherein the wastewater contains heavy metal ions;

[0006] Add a pre-prepared EDTA solution to the pretreated wastewater, stir until homogeneous, and after a preset reaction time, obtain a mixture.

[0007] Add flocculant to the mixture and stir evenly so that the heavy metal ions form a complex with EDTA and undergo flocculation and precipitation to obtain the precipitated wastewater.

[0008] The precipitated wastewater is subjected to solid-liquid separation to remove the complex precipitate of the heavy metal ions, thereby obtaining treated wastewater.

[0009] Furthermore, the pretreatment of the wastewater specifically includes:

[0010] Remove impurities from the wastewater and adjust the pH of the wastewater to the preset pH value.

[0011] Furthermore, the preset pH value is 6 to 8.

[0012] Furthermore, the concentration of the EDTA solution is 10–50 g / L.

[0013] Furthermore, the reaction time is 30–60 min.

[0014] Furthermore, the flocculant is at least polyaluminum chloride or polyacrylamide.

[0015] Furthermore, the solid-liquid separation of the precipitated wastewater specifically involves:

[0016] The wastewater after sedimentation is separated into solids and liquids using a sedimentation tank or a filter press.

[0017] Furthermore, the method also includes:

[0018] The treated wastewater is tested, and the wastewater is discharged after passing the test.

[0019] Compared with existing technologies, this invention provides a wastewater treatment method based on EDTA. First, the wastewater, containing heavy metal ions, is pretreated. Next, a pre-prepared EDTA solution is added to the pretreated wastewater, stirred until homogeneous, and after a preset reaction time, a mixed solution is obtained. Then, a flocculant is added to the mixed solution, stirred until homogeneous, allowing the heavy metal ions to form complexes with EDTA and undergo flocculation and precipitation, resulting in precipitated wastewater. Finally, the precipitated wastewater undergoes solid-liquid separation to remove the heavy metal ion complex precipitate, obtaining treated wastewater. This invention effectively removes heavy metal ions from wastewater and has advantages such as high efficiency and low cost. Attached Figure Description

[0020] Figure 1 This is a flowchart of a preferred embodiment of a wastewater treatment method based on EDTA provided by the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention provides a wastewater treatment method based on EDTA, see [link to relevant documentation]. Figure 1 The diagram shown is a flowchart of a preferred embodiment of a wastewater treatment method based on EDTA provided by the present invention, the method comprising steps S11 to S14:

[0023] Step S11: Pre-treat the wastewater; wherein the wastewater contains heavy metal ions;

[0024] Step S12: Add the pre-prepared EDTA solution to the pretreated wastewater, stir until homogeneous, and obtain a mixture after a preset reaction time;

[0025] Step S13: Add flocculant to the mixture and stir evenly so that the heavy metal ions form a complex with EDTA and undergo flocculation and precipitation to obtain the precipitated wastewater.

[0026] Step S14: Perform solid-liquid separation on the precipitated wastewater to remove the complex precipitate of the heavy metal ions and obtain treated wastewater.

[0027] In practice, the wastewater containing heavy metal ions is first pretreated. Then, a pre-prepared EDTA (ethylenediaminetetraacetic acid) solution is added to the pretreated wastewater, stirred thoroughly, and allowed to react for a predetermined time at room temperature to obtain a mixture of EDTA solution and wastewater. Next, a flocculant is added to the mixture and stirred until homogeneous, allowing the heavy metal ions in the mixture to react with EDTA, forming complexes that then flocculate and precipitate, resulting in precipitated wastewater. Finally, the precipitated wastewater undergoes solid-liquid separation to separate the heavy metal ion complex precipitates and remove them, yielding treated wastewater (i.e., wastewater with heavy metal ions removed).

[0028] It should be noted that the embodiments of the present invention can efficiently and effectively remove heavy metal ions from wastewater by using EDTA to form a stable complex with heavy metal ions. Furthermore, EDTA is inexpensive, which can effectively reduce wastewater treatment costs. At the same time, EDTA is a biodegradable and environmentally friendly reagent that will not cause secondary pollution to the environment. In addition, the process flow of the embodiments of the present invention is simple, easy to implement, and does not require complex equipment or technology.

[0029] In one optional embodiment, the pretreatment of wastewater specifically includes:

[0030] Remove impurities from the wastewater and adjust the pH of the wastewater to the preset pH value.

[0031] Specifically, in conjunction with the above embodiments, the present invention can remove suspended solids, grease and other impurities from wastewater during wastewater pretreatment, and adjust the pH value of the wastewater to a preset pH value.

[0032] In one optional embodiment, the preset pH value is 6 to 8.

[0033] Specifically, in conjunction with the above embodiments, when adjusting the pH value of wastewater to a preset pH value, the preset pH value can be 6 to 8. That is, when pretreating wastewater, the present invention can remove suspended solids, grease and other impurities from the wastewater and adjust the pH value of the wastewater to 6 to 8.

[0034] For example, the preset pH value can be 6, 7 or 8, or it can be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0035] In one optional embodiment, the concentration of the EDTA solution is 10–50 g / L.

[0036] Specifically, in conjunction with the above embodiments, when preparing the EDTA solution in advance, the concentration of the EDTA solution can be prepared to be 10 g / L to 50 g / L. That is, the concentration of the EDTA solution used in the embodiments of the present invention can be 10 g / L to 50 g / L.

[0037] For example, the concentration of the EDTA solution can be 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L, 20 g / L, 21 g / L, 22 g / L, 23 g / L, 24 g / L, 25 g / L, 26 g / L, 27 g / L, 28 g / L, 29 g / L, or 30 g / L. The concentrations can be 31g / L, 32g / L, 33g / L, 34g / L, 35g / L, 36g / L, 37g / L, 38g / L, 39g / L, 40g / L, 41g / L, 42g / L, 43g / L, 44g / L, 45g / L, 46g / L, 47g / L, 48g / L, 49g / L, or 50g / L, and can also be set according to actual needs. This embodiment of the invention does not impose specific limitations.

[0038] It should be noted that the amount of EDTA solution used in the embodiments of the present invention can be determined according to the concentration and type of heavy metal ions in the wastewater, and the embodiments of the present invention do not impose specific limitations.

[0039] In one optional embodiment, the reaction time is 30 to 60 minutes.

[0040] Specifically, in conjunction with the above embodiments, in this embodiment of the invention, a pre-prepared EDTA solution is added to pretreated wastewater, stirred thoroughly, and after a reaction time of 30 to 60 minutes at room temperature, a mixture of EDTA solution and wastewater is obtained.

[0041] For example, the reaction time can be 30 minutes, 31 minutes, 32 minutes, 33 minutes, 34 minutes, 35 minutes, 36 minutes, 37 minutes, 38 minutes, 39 minutes, 40 minutes, 41 minutes, 42 minutes, 43 minutes, 44 minutes, 45 minutes, 46 minutes, 47 minutes, 48 ​​minutes, 49 minutes, 50 minutes, 51 minutes, 52 minutes, 53 minutes, 54 minutes, 55 minutes, 56 minutes, 57 minutes, 58 minutes, 59 minutes, or 60 minutes, and can also be set according to actual needs. This embodiment of the invention does not impose specific limitations.

[0042] In one alternative embodiment, the flocculant is at least polyaluminum chloride or polyacrylamide.

[0043] Specifically, in conjunction with the above embodiments, the flocculant used in the embodiments of the present invention can be polyaluminum chloride or polyacrylamide. That is, in the embodiments of the present invention, polyaluminum chloride or polyacrylamide can be added to the mixture of EDTA solution and wastewater and stirred evenly, so that the heavy metal ions in the mixture react with EDTA to form complexes and flocculate and precipitate.

[0044] It is understood that, in addition to using polyaluminum chloride or polyacrylamide as flocculants, other types of flocculants may also be used in the embodiments of the present invention, and the embodiments of the present invention do not make specific limitations.

[0045] In one optional embodiment, the solid-liquid separation of the precipitated wastewater specifically involves:

[0046] The wastewater after sedimentation is separated into solids and liquids using a sedimentation tank or a filter press.

[0047] Specifically, in conjunction with the above embodiments, when performing solid-liquid separation treatment on the wastewater after sedimentation, the present invention can utilize a sedimentation tank or a filter press to perform solid-liquid separation treatment on the wastewater after sedimentation, so as to separate the complex precipitates of heavy metal ions contained in the wastewater after sedimentation, and remove the separated complex precipitates of heavy metal ions.

[0048] In one alternative embodiment, the method further includes:

[0049] The treated wastewater is tested, and the wastewater is discharged after passing the test.

[0050] Specifically, in conjunction with the above embodiments, after obtaining the treated wastewater, the present invention can also test the obtained treated wastewater, and after passing the test, the wastewater can be discharged.

[0051] Based on all the above embodiments, the implementation process of this scheme is described below through the first specific embodiment, including: (1) Wastewater pretreatment: pretreatment of wastewater containing heavy metal ions to remove suspended solids, grease and other impurities in the wastewater, and adjusting the pH value of the wastewater to 6; (2) EDTA treatment: adding a pre-prepared EDTA (ethylenediaminetetraacetic acid) solution with a concentration of 10g / L to the pretreated wastewater, stirring thoroughly, and after a reaction time of 60min at room temperature, a mixture of EDTA solution and wastewater is obtained accordingly; wherein, the amount of EDTA solution used can be determined according to the concentration and type of heavy metal ions in the wastewater; (3) Flocculation and sedimentation treatment: adding EDTA solution to the wastewater... Add flocculant (e.g., polyaluminum chloride or polyacrylamide) to the mixture of TA solution and wastewater, and stir evenly so that the heavy metal ions in the mixture react with EDTA to form complexes and flocculate and precipitate, thereby obtaining the precipitated wastewater; (4) Solid-liquid separation treatment: use a sedimentation tank or filter press to perform solid-liquid separation treatment on the precipitated wastewater to separate the complex precipitates of heavy metal ions contained in the precipitated wastewater, and remove the separated complex precipitates of heavy metal ions, thereby obtaining the treated wastewater (i.e., wastewater in which heavy metal ions have been removed); (5) Wastewater discharge: test the obtained treated wastewater, and discharge the wastewater after it passes the test.

[0052] Based on all the above embodiments, the implementation process of this scheme is described below through a second specific embodiment, including: (1) Wastewater pretreatment: pretreatment of wastewater containing heavy metal ions to remove suspended solids, grease and other impurities from the wastewater, and adjusting the pH of the wastewater to 7; (2) EDTA treatment: adding a pre-prepared EDTA (ethylenediaminetetraacetic acid) solution with a concentration of 30 g / L to the pretreated wastewater, stirring thoroughly, and after a reaction time of 45 min at room temperature, obtaining a mixture of EDTA solution and wastewater; wherein, the amount of EDTA solution used can be determined according to the concentration and type of heavy metal ions in the wastewater; (3) Flocculation and sedimentation treatment: adding EDTA solution to the wastewater... Add flocculant (e.g., polyaluminum chloride or polyacrylamide) to the mixture of TA solution and wastewater, and stir evenly so that the heavy metal ions in the mixture react with EDTA to form complexes and flocculate and precipitate, thereby obtaining the precipitated wastewater; (4) Solid-liquid separation treatment: use a sedimentation tank or filter press to perform solid-liquid separation treatment on the precipitated wastewater to separate the complex precipitates of heavy metal ions contained in the precipitated wastewater, and remove the separated complex precipitates of heavy metal ions, thereby obtaining the treated wastewater (i.e., wastewater in which heavy metal ions have been removed); (5) Wastewater discharge: test the obtained treated wastewater, and discharge the wastewater after it passes the test.

[0053] Based on all the above embodiments, the implementation process of this scheme is described below through a third specific embodiment, including: (1) Wastewater pretreatment: pretreatment of wastewater containing heavy metal ions to remove suspended solids, grease and other impurities from the wastewater, and adjusting the pH value of the wastewater to 8; (2) EDTA treatment: adding a pre-prepared EDTA (ethylenediaminetetraacetic acid) solution with a concentration of 50 g / L to the pretreated wastewater, stirring thoroughly, and after a reaction time of 30 min at room temperature, obtaining a mixture of EDTA solution and wastewater; wherein, the amount of EDTA solution used can be determined according to the concentration and type of heavy metal ions in the wastewater; (3) Flocculation and sedimentation treatment: adding EDTA solution to the wastewater... Add flocculant (e.g., polyaluminum chloride or polyacrylamide) to the mixture of TA solution and wastewater, and stir evenly so that the heavy metal ions in the mixture react with EDTA to form complexes and flocculate and precipitate, thereby obtaining the precipitated wastewater; (4) Solid-liquid separation treatment: use a sedimentation tank or filter press to perform solid-liquid separation treatment on the precipitated wastewater to separate the complex precipitates of heavy metal ions contained in the precipitated wastewater, and remove the separated complex precipitates of heavy metal ions, thereby obtaining the treated wastewater (i.e., wastewater in which heavy metal ions have been removed); (5) Wastewater discharge: test the obtained treated wastewater, and discharge the wastewater after it passes the test.

[0054] In summary, the wastewater treatment method based on EDTA provided by this invention involves: first, pretreating the wastewater, which contains heavy metal ions; then, adding a pre-prepared EDTA solution to the pretreated wastewater, stirring until homogeneous, and obtaining a mixture after a preset reaction time; next, adding a flocculant to the mixture, stirring until homogeneous, so that the heavy metal ions form complexes with EDTA and undergo flocculation and precipitation, obtaining precipitated wastewater; finally, performing solid-liquid separation on the precipitated wastewater to remove the heavy metal ion complex precipitate, obtaining treated wastewater; and finally, testing the obtained treated wastewater, and discharging it after passing the test. This invention has the following beneficial effects:

[0055] (1) High efficiency in removing heavy metals: By using EDTA to form a stable complex with heavy metal ions, heavy metal ions in wastewater can be removed efficiently and effectively.

[0056] (2) Low cost: EDTA is inexpensive and can effectively reduce wastewater treatment costs;

[0057] (3) Environmental protection and safety: EDTA is a biodegradable and environmentally friendly reagent that will not cause secondary pollution to the environment;

[0058] (4) Easy to operate: The process is simple and easy to implement, without the need for complex equipment or technology.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wastewater treatment method based on EDTA, characterized in that, include: Wastewater is pretreated; wherein the wastewater contains heavy metal ions; Add a pre-prepared EDTA solution to the pretreated wastewater, stir until homogeneous, and after a preset reaction time, obtain a mixture. Add flocculant to the mixture and stir evenly so that the heavy metal ions form a complex with EDTA and undergo flocculation and precipitation to obtain the precipitated wastewater. The precipitated wastewater is subjected to solid-liquid separation to remove the complex precipitate of the heavy metal ions, thereby obtaining treated wastewater.

2. The wastewater treatment method based on EDTA as described in claim 1, characterized in that, The pretreatment of wastewater specifically includes: Remove impurities from the wastewater and adjust the pH of the wastewater to the preset pH value.

3. The wastewater treatment method based on EDTA as described in claim 2, characterized in that, The preset pH value is 6 to 8.

4. The wastewater treatment method based on EDTA as described in claim 1, characterized in that, The concentration of the EDTA solution is 10–50 g / L.

5. The wastewater treatment method based on EDTA as described in claim 1, characterized in that, The reaction time is 30–60 min.

6. The wastewater treatment method based on EDTA as described in claim 1, characterized in that, The flocculant is at least polyaluminum chloride or polyacrylamide.

7. The wastewater treatment method based on EDTA as described in claim 1, characterized in that, The solid-liquid separation of the precipitated wastewater specifically involves: The wastewater after sedimentation is separated into solids and liquids using a sedimentation tank or a filter press.

8. The wastewater treatment method based on EDTA as described in any one of claims 1 to 7, characterized in that, The method further includes: The treated wastewater is tested, and the wastewater is discharged after passing the test.

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