Method for removing CODMn in drinking water based on oxidative polymerization

Abstract

The invention discloses a method for removing CODMn in drinking water based on oxidative polymerization, relates to a method for removing CODMn in drinking water by oxidative polymerization of organic pollutants in drinking water in a process of activating permanganate with a carbon material, and relates to the field of drinking water treatment. The core technology of the invention is as follows: high-efficiency removal of CODMn in drinking water is realized by using a common oxidant permanganate in drinking water pretreatment and adding a carbon material at the same time. According to the method, the effective utilization rate of the oxidizing agent is increased, and pollutants are easier to be enriched on the surface of the catalyst in a polymer form, so that organic pollutants in water are efficiently oxidized, transferred and removed towards the surface of a solid, and the method has the characteristic of efficiently removing CODMn. The technology has the advantages of being easy and convenient to operate, low in cost, environmentally friendly, not prone to being interfered by background matrixes and the like, has wide application prospects in the field of drinking water pollution control, and is a new innovation based on pollutant characteristics and a drinking water pretreatment technology.

Description

Technical Field

[0001] This invention relates to the field of drinking water pretreatment, and in particular to a method for removing COD from drinking water based on oxidative polymerization. Mn The method. Background Technology

[0002] Ensuring safe drinking water is crucial for maintaining human health and promoting social progress. However, the problem of drinking water pollution remains severe globally. Data from 2023 shows that approximately 2.2 billion people worldwide still lack access to safe drinking water. With accelerating modernization and continued population growth, the environmental pressure on water sources is significantly increasing. It has been reported that in 2023, the permanganate index (COD) in my country's surface water... Mn The exceedance rate was as high as 4.8%, which not only affects the quality of drinking water but also potentially endangers human health. To ensure drinking water safety, effective treatment and purification measures must be taken. This is not only a necessary means to protect public health but also an important measure to achieve sustainable development.

[0003] Currently, the core treatment processes for conventional drinking water in my country mainly include coagulation, sedimentation, filtration, and disinfection units. However, the traditional coagulation process has limitations in COD control. Mn Its removal efficiency is limited, making it difficult to deal with COD. Mn The problem of excessive COD levels in drinking water necessitates the introduction of pretreatment processes. Mn The removal of pollutants is a common process. Permanganate (Mn(VII)) is a commonly used pre-oxidant with good oxidizing power over a wide pH range. Its reduction product, manganese dioxide, has adsorption and coagulation effects, enhancing pollutant removal. However, Mn(VII) has limited oxidizing power and is selective in oxidizing pollutants. Furthermore, its concentration must be limited to below 1.2 mg / L to avoid residual color. Therefore, to improve the oxidizing power of Mn(VII), many researchers have conducted studies on enhancing Mn(VII) in recent years. These enhanced Mn(VII) technologies include Lewis acid-catalyzed Mn(VII) oxidation, complexing agent-activated Mn(VII) oxidation, photoelectric activation of Mn(VII) oxidation, and reducing agent-activated Mn(VII) oxidation. However, while these enhanced Mn(VII) technologies can effectively degrade parent organic pollutants, they are difficult to mineralize them into carbon dioxide and water. Therefore, these enhanced Mn(VII) technologies are insufficient to address COD in water. Mn The problem of excessive levels of Mn(VII) is urgent. There is an urgent need to develop new Mn(VII) enhancement methods to improve COD levels in water. Mn The removal effect. Summary of the Invention

[0004] This invention provides a method for removing COD from drinking water based on oxidative polymerization. Mn The method involves a carbon material-activated permanganate process to oxidize and polymerize organic pollutants in drinking water, thereby removing COD from the drinking water. Mn The method includes the following steps: (1) Adjusting the pH of the reaction solution containing a certain concentration of natural organic matter to the range of 6.0 to 9.0; (2) Adding a certain amount of carbon material to the reaction solution to be treated, dispersing it ultrasonically and stirring for 30 min; (3) Adding a certain concentration of Mn(VII) to the reaction solution in step (2) and reacting for a period of time.

[0005] In the above method, the carbon material is single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, activated carbon, graphite, biochar, etc.; the Mn(VII) is potassium permanganate, sodium permanganate, calcium permanganate, etc.; the natural organic matter in the reaction solution is humic acid (HA), fulvic acid (FA), algal organic matter (AOM), etc.; the concentration of the natural organic matter is COD. Mn ≥6 mg / L; the mass ratio of Mn(VII) to natural organic matter in the reaction solution is 0.8:1 to 8:1; the amount of carbon material added in the reaction solution is 0.1 g / L to 1 g / L; the mixing method is magnetic stirring; the pH of the reaction system is 6.0 to 9.0.

[0006] The beneficial effects of the invention are as follows: (1) The present invention is a system constructed by coupling permanganate, a commonly used pre-oxidant in drinking water, and carbon materials, which has the advantages of simple operation, low cost and environmental friendliness; (2) The carbon material / Mn(VII) system in this invention overcomes the problem of low mineralization rate in the previous permanganate activation system, and can efficiently remove COD from the solution. Mn This improves the efficiency of the water treatment process; (3) The present invention can achieve COD under drinking water pH conditions. Mn It has a high efficiency in removing pollutants and will not cause drastic changes in the pH of the water during use; (4) The present invention has significant advantages in practical applications and can effectively avoid common problems such as color increase and manganese ion residue in the pre-oxidation process of permanganate. Attached Figure Description

[0007] Figure 1 In Example 1, when Mn(VII):HA = 1:1, the carbon nanotube / Mn(VII) system removes COD. Mn kinetic curve; Figure 2In Example 2, when Mn(VII):HA = 2:1, the carbon nanotube / Mn(VII) system removes COD. Mn kinetic curve; Figure 3 In Example 3, when Mn(VII):HA = 3:1, the carbon nanotube / Mn(VII) system removes COD. Mn kinetic curve; Figure 4 In Example 4, when carbon nanotubes = 0.25 g / L, the carbon nanotube / Mn(VII) system removes COD. Mn kinetic curve; Figure 5 In Example 5, when carbon nanotubes = 0.75 g / L, the carbon nanotube / Mn(VII) system removes COD. Mn kinetic curve; Figure 6 For the COD removal of the carbon nanotube / Mn(VII) system at pH = 8.0 in Example 6. Mn The dynamic curve. Detailed Implementation Example 1

[0008] Humic acid (HA) was selected as the target pollutant, and the effect of the system on COD under the condition of Mn(VII):HA = 1:1 was investigated. Mn The removal efficiency. The specific steps are as follows: (1) Add a certain concentration of HA to the reaction solution and adjust the pH to 7.5; (2) Add a certain amount of carbon nanotubes to the reaction solution in step (1), disperse by ultrasonication and mix for 30 min; (3) Add a certain concentration of Mn(VII) to the solution in step (2) and react for 1 h.

[0009] The natural organic compound is HA; the certain concentration is COD. Mn = 6 mg / L; the mixing method is magnetic stirring; the carbon nanotubes are multi-walled carbon nanotubes (MWCNTs); the specified amount is 0.5 g / L; the Mn(VII) is KMnO4, and the initial concentration of added Mn(VII) is 30 μmol•L. −1 The reaction solution has a reaction pH of 7.5.

[0010] Figure 1 The COD in the MWCNT / Mn(VII) system is shown. Mn The removal status. When Mn(VII):HA = 1:1, COD Mn The removal rate was 56%. Example 2

[0011] HA was selected as the target pollutant, and the effect of the system on COD was investigated under the condition that Mn(VII):HA = 2:1. Mn The removal efficiency was improved. Unlike the steps in Example 1, the initial concentration of Mn(VII) in the reaction solution was 60 μmol•L. −1 .

[0012] Figure 2 The COD in the MWCNT / Mn(VII) system is shown. Mn The removal status. When Mn(VII):HA = 2:1, COD Mn The removal rate was 73%. Example 3

[0013] HA was selected as the target pollutant, and the effect of the system on COD was investigated under the condition that Mn(VII):HA = 3:1. Mn The removal efficiency was improved. Unlike the steps in Example 1, the initial concentration of Mn(VII) in the reaction solution was 90 μmol•L. −1 .

[0014] Figure 2 The COD in the MWCNT / Mn(VII) system is shown. Mn The removal status. When Mn(VII):HA = 3:1, COD Mn The removal rate was 82.27%. Example 4

[0015] HA was selected as the target pollutant, and the effect of the system on COD was investigated under the condition of Mn(VII):HA = 3:1 and a MWCNT dosage of 0.25 g / L. Mn The removal efficiency was improved. Unlike the steps in Example 1, the initial concentration of Mn(VII) in the reaction solution was 90 μmol•L. −1 The dosage of MWCNT is 0.25 g / L.

[0016] Figure 4 The COD in the MWCNT / Mn(VII) system is shown. Mn The removal status. When Mn(VII):HA = 3:1 and the MWCNT dosage is 0.25 g / L, COD Mn The removal rate was 45%. Example 5

[0017] HA was selected as the target pollutant, and the effect of the system on COD was investigated under the condition of Mn(VII):HA = 3:1 and a MWCNT dosage of 0.75 g / L. MnThe removal efficiency was improved. Unlike the steps in Example 1, the initial concentration of Mn(VII) in the reaction solution was 90 μmol•L. −1 The dosage of MWCNT is 0.75 g / L.

[0018] Figure 5 The COD in the MWCNT / Mn(VII) system is shown. Mn The removal status. When Mn(VII):HA = 3:1 and the MWCNT dosage is 0.75 g / L, COD Mn The removal rate was 70%. Example 6

[0019] HA was selected as the target pollutant, and the effect of the system on COD was investigated at pH = 8.0, Mn(VII):HA = 3:1, and MWCNT dosage of 0.5 g / L. Mn The removal efficiency was improved. Unlike the steps in Example 1, the initial concentration of Mn(VII) in the reaction solution was 90 μmol•L. −1 The dosage of MWCNT is 0.5 g / L, and the pH of the reaction solution is 8.0.

[0020] Figure 6 The COD in the MWCNT / Mn(VII) system is shown. Mn The removal status. When pH = 8.0, Mn(VII):HA = 3:1, and MWCNT dosage is 0.5 g / L, COD Mn The removal rate was 79%.

Claims

1. A method for removing COD from drinking water based on oxidative polymerization Mn The method is characterized by, The steps include: (1) adjusting the pH of the reaction solution containing a certain concentration of natural organic matter to the range of 6.0 to 9.0; (2) adding a certain amount of carbon material to the reaction solution to be treated, dispersing it ultrasonically and stirring for 30 min; (3) adding a certain concentration of permanganate to the reaction solution in step (2) and reacting for a period of time.

2. The method for removing COD from drinking water based on oxidative polymerization according to claim 1 Mn The method is characterized by: The carbon materials mentioned include single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, activated carbon, graphite, biochar, etc.

3. The method for removing COD from drinking water based on oxidative polymerization according to claim 1 Mn The method is characterized by: The permanganate mentioned above is potassium permanganate, sodium permanganate, calcium permanganate, etc.

4. The method for removing COD from drinking water based on oxidative polymerization according to claim 1 Mn The method is characterized by: The stirring method described is magnetic stirring.

5. A method for removing COD from drinking water based on oxidative polymerization as described in claim 1. Mn The method is characterized by: The reaction pH of the method described is 6.0~9.

0.

6. The method for removing COD from drinking water based on oxidative polymerization according to claim 1 Mn The method is characterized by: The reaction solution contains Mn(VII) and natural organic matter (in the form of COD). Mn The mass ratio of (calculated) is 0.8:1 to 8:

1.

7. A method for removing COD from drinking water based on oxidative polymerization as described in claim 1 Mn The method is characterized by: The amount of carbon material added to the reaction solution is 0.1 g / L to 1 g / L.

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