A method for simultaneously removing manganese and organic pollutants in manganese-containing groundwater by using a complexing agent and sodium sulfite

Abstract

The present application relates to a kind of method for simultaneously removing manganese and organic pollutants in manganese-containing groundwater using complexing agent and sodium sulfite.The present application provides a kind of groundwater containing Mn (II) and organic pollutants;Complexing agent and sodium sulfite are added to the groundwater, and mixed to obtain a mixed solution, the pH of the mixed solution is adjusted to acidic or neutral, the reaction is continued, and the simultaneous removal of manganese and organic pollutants in groundwater is realized.The method of the present application can effectively remove manganese and organic pollutants in groundwater simultaneously.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a method for simultaneously removing manganese and organic pollutants from manganese-containing groundwater using a complexing agent and sodium sulfite. Background Technology

[0002] Manganese is a trace element essential for human metabolism, but excessive intake can have chronic toxic effects, causing abnormalities in the nervous system and endocrine disorders. While organic pollutants may not be present in high concentrations in water, they are prone to bioaccumulation and have strong toxic side effects, posing risks of cancer and birth defects. Therefore, the simultaneous removal of manganese and organic pollutants from groundwater is of great significance for human health and the ecological environment.

[0003] Currently, manganese removal methods include: natural contact oxidation, but this method is time-consuming and has low manganese removal efficiency; chlorination removal is too costly; and biological manganese fixation removal has a long time cycle and cannot simultaneously remove organic matter. Organic pollutants are difficult to degrade in conventional water treatment processes. Currently, commonly used methods for treating organic pollutants in water mainly include biodegradation and chemical oxidation. Biodegradation generally has disadvantages such as long processing time, significant environmental influence on microorganisms, and difficulty in guaranteeing effluent quality. Commonly used chemical oxidation methods, such as ozone oxidation, have drawbacks such as high energy consumption, low ozone utilization rate, risk of producing bromate byproducts, a narrow applicable pH range for Fenton oxidation, significant pH influence, and easy precipitation of ferrous ions, making it impossible to simultaneously and efficiently remove manganese and organic matter. Therefore, a green, environmentally friendly, and easy-to-operate method is needed to simultaneously remove manganese and organic matter from groundwater.

[0004] To effectively remove manganese and organic pollutants from groundwater, this invention proposes a method for simultaneously removing manganese and organic pollutants from manganese-containing groundwater using a complexing agent and sodium sulfite. Summary of the Invention

[0005] To address the above technical problems, this invention provides a method for simultaneously removing manganese and organic pollutants from manganese-containing groundwater using a complexing agent and sodium sulfite.

[0006] The purpose of this invention is to provide a method for simultaneously removing manganese and organic pollutants from manganese-containing groundwater using a complexing agent and sodium sulfite, comprising the following steps:

[0007] Provide a groundwater containing Mn(II) and organic pollutants;

[0008] Complexing agent and sodium sulfite are added to groundwater and mixed to obtain a mixture. The pH of the mixture is adjusted to acidic or neutral, and the reaction continues to achieve the simultaneous removal of manganese and organic pollutants from groundwater.

[0009] In some embodiments of the present invention, the Mn(II) content in the groundwater is 0.5 mg / L to 1 mg / L.

[0010] In some embodiments of the present invention, the content of organic pollutants in the groundwater is 100 ng / L to 200 ng / L.

[0011] In some embodiments of the present invention, the organic pollutants include antibiotics and endocrine disruptors, including one or more of sulfamethoxazole, sulfamethazine, levofloxacin, norfloxacin, bisphenol A, triclosan, and nonylphenol.

[0012] In some embodiments of the present invention, the molar ratio of Mn(II) to complexing agent in the groundwater is 1:2 to 1:10; the molar ratio of Mn(II) to sodium sulfite is 1:2 to 1:20.

[0013] In some embodiments of the present invention, the sodium sulfite is selected from sodium sulfite and / or potassium sulfite.

[0014] In some embodiments of the present invention, the complexing agent is selected from one or more of tannic acid, gallic acid, gallic acid, hypozinogenin, citric acid, protocatechuic acid, vanillic acid, ethylenediaminetetraacetic acid, and 2-pyridinecarboxylic acid.

[0015] In some embodiments of the present invention, the reaction time is 15 min to 30 min. Exemplarily, it can be 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, etc., or any interval between any two values.

[0016] In some embodiments of the present invention, the pH value of the mixture is adjusted to 5 to 7. In particular, it can be 5, 5.5, 6, 6.5, 7, or any range between any two values.

[0017] Preferably, the pH of the mixture is adjusted to 5.5–6.

[0018] Preferably, the pH of the mixture is adjusted to 6 to 6.5.

[0019] The principle of this invention is as follows: Soluble Mn(II) in groundwater is utilized, and appropriate amounts of a complexing agent and sodium sulfite are added. Mn(II) reacts with the complexing agent to produce a Mn(II)-complexing agent. The sodium sulfite is then catalyzed by the generated Mn(II)-complexing agent and undergoes a chain reaction to transform into SO5, which has oxidizing properties.·- With HSO5 - Meanwhile, Mn(II)-complexing agents are oxidized to Mn(III)-complexing agents, and Mn(III)-complexing agents can be further oxidized to Mn(V)-complexing agents.

[0020] Active Mn(III) and Mn(V) can rapidly oxidize and decompose organic pollutants. In addition, active manganese is converted into MnO2. As the reaction proceeds, MnO2 gradually aggregates into particles, which can adsorb the remaining Mn(II) in the water onto the surface, thereby achieving the simultaneous removal of manganese and organic pollutants from groundwater.

[0021] The technical solution of the present invention has the following advantages compared with the prior art:

[0022] This invention, by adding a complexing agent and sodium sulfite, can directly oxidize Mn(II) in groundwater to Mn(V), thereby achieving rapid oxidative decomposition of organic pollutants. The intermediate manganese product MnO2 can effectively adsorb the remaining Mn(II), thus achieving simultaneous removal of manganese and organic pollutants from groundwater.

[0023] This invention is suitable for water quality conditions of pH 3 to 8, and the method is simple, the reagents used are green and environmentally friendly, the cost is low, and the operation is highly operable. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0025] Example 1:

[0026] This embodiment provides a method for simultaneously removing manganese and organic pollutants from manganese-containing groundwater using a complexing agent and sodium sulfite, as detailed below:

[0027] Step 1: Provide a groundwater, wherein the content of Mn(II) in the groundwater is 0.5 mg / L and the content of sulfamethoxazole is 150 ng / L.

[0028] Step 2: Based on the Mn(II) content in Step 1, determine the dosage of tannic acid and sodium sulfite using a molar ratio of Mn(II):tannic acid:sodium sulfite of 1:5:10. Mix the groundwater, tannic acid, and sodium sulfite to obtain a mixed solution. Adjust the pH of the mixed solution to 6 and continue the reaction for 20 minutes. Filter the reaction solution to obtain filtrate and filter residue. After the reaction is complete, use ICP-OES to quantitatively detect the remaining Mn(II) content in the filtrate (filtered groundwater), and use high performance liquid chromatography to quantitatively detect the sulfamethoxazole content in the filtrate (filtered groundwater). Compare the results with the original groundwater to determine the removal rates of Mn(II) and sulfamethoxazole. The experimental results are shown in Table 1.

[0029] Example 2:

[0030] Unlike Example 1, the pH of the mixture was adjusted to pH 5. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0031] Example 3:

[0032] Unlike Example 1, the pH of the mixture was adjusted to pH 7. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0033] Example 4:

[0034] Unlike Example 1, the reaction time in this example was 15 min. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0035] Example 5:

[0036] Unlike Example 1, the reaction time in this example was 30 min. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0037] Example 6:

[0038] Unlike Example 1, the complexing agent selected in this example is gallic acid. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0039] Example 7:

[0040] Unlike Example 1, gallic acid was chosen as the complexing agent. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0041] Example 8:

[0042] Unlike Example 1, the complexing agent was selected as hyponitrotriacetic acid. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0043] Example 9:

[0044] Unlike Example 1, the molar ratio of Mn(II):complexing agent:sodium sulfite was 1:2:10. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0045] Example 10:

[0046] Unlike Example 1, the molar ratio of Mn(II):complexing agent:sodium sulfite was 1:10:10. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0047] Example 11:

[0048] Unlike Example 1, the molar ratio of Mn(II):complexing agent:sodium sulfite was 1:5:2. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0049] Example 12:

[0050] Unlike Example 1, the molar ratio of Mn(II):complexing agent:sodium sulfite was 1:5:5. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0051] Example 13:

[0052] Unlike Example 1, the molar ratio of Mn(II):complexing agent:sodium sulfite was 1:5:20. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0053] Comparative Example 1:

[0054] Unlike Example 1, no complexing agent was added in this comparative example. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0055] Comparative Example 2:

[0056] Unlike Example 1, sodium sulfite was not added in this comparative example. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0057] Table 1

[0058]

[0059]

[0060] As shown in the table above, examples 1-3 demonstrate that pH affects the removal rates of Mn(II) and sulfamethoxazole in this invention. The removal effect of sulfamethoxazole is better at pH=6. Lower pH affects the conversion of MnO2 in the reaction system, inhibiting the removal of Mn(II), while higher pH affects the formation and stability of active species in the reaction system, resulting in poor removal of sulfamethoxazole. The optimal treatment effect is achieved at pH=6.

[0061] As can be seen from Examples 1, 4, and 5, the reaction time of the system affects the removal effect. When the reaction time is 20 min, not only is the removal rate good, but time costs are also saved. If the reaction time is insufficient, the active species cannot effectively remove organic pollutants, and the conversion rate of MnO2 is low, resulting in insufficient adsorption capacity for Mn(II).

[0062] As can be seen from Examples 1, 6, 7, and 8, the four complexing agents have similar removal effects on sulfamethoxazole and Mn(II), and each has its own advantages.

[0063] Examples 1 and 9-13 show that the molar ratio of Mn(II), complexing agent, and sodium sulfite has a certain impact on the removal rates of manganese and sulfamethoxazole. A molar ratio of 1:5:10 for Mn(II), complexing agent, and sodium sulfite yields the best results. Lower concentrations of the complexing agent reduce the conversion and stability of the active intermediate, leading to an overall decrease in removal rate. Lower concentrations of sodium sulfite result in lower HSO5 concentrations. - Insufficient sodium sulfite formation can hinder subsequent reactions. When the concentration of sodium sulfite is high, it competes with HSO5 for its own energy. - The presence of active intermediates leads to poor removal efficiency.

[0064] As can be seen from Example 1 and Comparative Examples 1-2, without a complexing agent, Mn(II) cannot effectively activate sodium sulfite to generate HSO5. - Therefore, Mn(V) and MnO2 cannot be generated. Without sodium sulfite, HSO3 cannot be generated. - Subsequent reactions cannot proceed, and simultaneous removal of manganese and organic matter cannot be achieved.

[0065] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for simultaneously removing manganese and organic pollutants from manganese-containing groundwater using a complexing agent and sodium sulfite, characterized in that, Includes the following steps: Provide a groundwater containing Mn(II) and organic pollutants; A complexing agent and sodium sulfite were added to groundwater and mixed to obtain a mixture. During this process, Mn(II) reacted with the complexing agent to produce a Mn(II) complexing agent. Sodium sulfite was then catalyzed by the generated Mn(II) complexing agent and ablated, undergoing a chain reaction to transform into SO5, which has oxidizing properties. ·- With HSO5 - Meanwhile, Mn(II) complexing agents are oxidized to Mn(III) complexing agents, and Mn(III) complexing agents can be further oxidized to Mn(V) complexing agents. The pH of the mixture is adjusted to acidic or neutral. Active Mn(III) and Mn(V) oxidize and decompose organic pollutants, and active manganese is converted into MnO2. As the reaction proceeds, MnO2 gradually agglomerates into particles, adsorbing the remaining Mn(II) in the water onto the surface. The reaction continues, achieving the simultaneous removal of manganese and organic pollutants from groundwater. The Mn(II) content in the groundwater is 0.1 mg / L to 1 mg / L; The content of organic pollutants in the groundwater is 100 ng / L to 200 ng / L; The molar ratio of Mn(II) to complexing agent in the groundwater is 1:2-1:10; the molar ratio of Mn(II) to sodium sulfite is 1:2-1:

20. The complexing agent is selected from one or more of tannic acid, gallic acid, gallic acid, and hypozinogen triacetic acid; The reaction time is 15 min to 30 min; Adjust the pH of the mixture to 5-7.

2. The method according to claim 1, characterized in that, The organic pollutants include antibiotics and endocrine disruptors.

3. The method according to claim 1, characterized in that, The sodium sulfite was replaced with potassium sulfite.

4. The method according to claim 1, characterized in that, Adjust the pH of the mixture to 5.5-6.

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