Method for synchronously removing manganese and organic pollutants in manganese-containing underground water by using complexing agent and sodium sulfite

Abstract

The invention relates to a method for synchronously removing manganese and organic pollutants in manganese-containing underground water by using a complexing agent and sodium sulfite. The invention provides underground water containing Mn (II) and organic pollutants. The method comprises the following steps: adding a complexing agent and sodium sulfite into underground water, mixing to obtain a mixed solution, adjusting the pH value of the mixed solution to be acidic or neutral, and continuously reacting to realize simultaneous removal of manganese and organic pollutants in the underground water. According to the method, manganese and organic pollutants in underground water can be effectively removed at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, in particular to a method for synchronously removing manganese and organic pollutants in manganese-containing groundwater by using a complexing agent and sodium sulfite. Background Art

[0003] Manganese is a trace element required for human metabolism, but excessive intake of manganese has a chronic toxic effect on the human body, causing abnormalities in the nervous system and endocrine function. Although the concentration of organic pollutants in water is not high, they are easy to bioaccumulate and have strong toxic side effects, posing the risk of carcinogenicity and teratogenicity. Therefore, the simultaneous removal of manganese and organic pollutants in groundwater is of great significance to human health and the ecological environment.

[0004] At present, the methods for manganese removal are: natural contact oxidation method, but this method is time-consuming and has low manganese removal efficiency; chlorine oxidation removal method is too expensive; biological manganese solidification and removal method has a long time cycle, and none of them can remove organic matter simultaneously. Organic pollutants are difficult to degrade in conventional water treatment processes. Currently, the commonly used methods for treating organic pollutants in water mainly include biodegradation and chemical oxidation. The biodegradation method is generally time-consuming, microorganisms are greatly affected by the environment, and the water quality of the effluent is difficult to guarantee. Commonly used chemical oxidation methods such as ozone oxidation have high energy consumption, low ozone utilization rate and the risk of producing bromate by-products, Fenton oxidation method has a narrow applicable pH range, is greatly affected by pH, and ferrous ions are easy to precipitate. It is not possible to remove manganese and organic matter simultaneously in a green and efficient manner. Therefore, a green, environmentally friendly and easy-to-operate method is needed to achieve the simultaneous removal of manganese and organic matter in groundwater.

[0005] In order to effectively remove manganese and organic pollutants in groundwater, the present invention provides a method for simultaneously removing manganese and organic pollutants in manganese-containing groundwater by using a complexing agent and sodium sulfite. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for simultaneously removing manganese and organic pollutants in manganese-containing groundwater by using a complexing agent and sodium sulfite.

[0007] The object of the present invention is to provide a method for simultaneously removing manganese and organic pollutants in manganese-containing groundwater by using a complexing agent and sodium sulfite, comprising the following steps:

[0008] Provide a groundwater containing Mn(II) and organic contaminants;

[0009] The chelating agent and sodium sulfite are added into the groundwater and mixed to obtain a mixed solution. The pH value of the mixed solution is adjusted to acidic or neutral, and the reaction is continued to achieve the simultaneous removal of manganese and organic pollutants in the groundwater.

[0010] In some embodiments of the present invention, the content of Mn(II) in the groundwater is 0.5 mg / L to 1 mg / L.

[0011] In some embodiments of the present invention, the content of organic pollutants in the groundwater is 100 ng / L to 200 ng / L.

[0012] In some embodiments of the present invention, the organic pollutants include antibiotics and endocrine disruptors, including one or more of sulfamethoxazole, sulfamethoxazole, levofloxacin, norfloxacin, bisphenol A, triclosan, and nonylphenol.

[0013] In some embodiments of the present invention, the molar ratio of Mn(II) to the complexing agent in the groundwater is 1:2-1:10; the molar ratio of Mn(II) to sodium sulfite is 1:2-1:20.

[0014] In some embodiments of the present invention, the sodium sulfite is selected from sodium sulfite and / or potassium sulfite.

[0015] In some embodiments of the present invention, the complexing agent is selected from one or more of tannic acid, gallic acid, gallic acid, nitrilotriacetic acid, citric acid, protocatechuic acid, vanillic acid, ethylenediaminetetraacetic acid, and 2-picolinic acid.

[0016] 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. It can be 15 min to 20 min; 20 min to 30 min, etc., or any interval value between any two values.

[0017] In some embodiments of the present invention, the pH value of the mixed solution is adjusted to 5 to 7. For example, it can be 5, 5.5, 6, 6.5, 7, etc., or any interval between any two values.

[0018] Preferably, the pH value of the mixed solution is adjusted to 5.5-6.

[0019] Preferably, the pH value of the mixed solution is adjusted to 6-6.5.

[0020] The principle of the present invention is as follows: using soluble Mn(II) in groundwater, adding appropriate amounts of complexing agent and sodium sulfite, Mn(II) and complexing agent react to produce Mn(II)-complexing agent. Sodium sulfite is catalyzed by the generated Mn(II)-complexing agent to undergo self-oxidation and undergo a chain reaction to be converted into SO5 with oxidizing properties.·- With HSO 5- At the same time, the Mn(II)-complexing agent will be oxidized to form a Mn(III)-complexing agent, and the Mn(III)-complexing agent can be further oxidized to form a Mn(V)-complexing agent.

[0021] Active Mn(III) and Mn(V) can rapidly oxidize and decompose organic pollutants, and 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 on the surface, thereby achieving the simultaneous removal of manganese and organic pollutants in groundwater.

[0022] The above technical solution of the present invention has the following advantages compared with the prior art:

[0023] The present invention can directly oxidize Mn(II) in groundwater into Mn(V) by adding a complexing agent and sodium sulfite, thereby realizing rapid oxidation and decomposition of organic pollutants. The intermediate manganese product MnO2 can effectively adsorb the remaining Mn(II), thereby realizing the simultaneous removal of manganese and organic pollutants in groundwater.

[0024] The invention is suitable for water quality conditions of pH 3-8, and the method is simple, the use of chemicals is green and environmentally friendly, the cost is low, and the operability is strong. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0026] Embodiment 1:

[0027] This embodiment provides a method for simultaneously removing manganese and organic pollutants in manganese-containing groundwater using a complexing agent and sodium sulfite, as follows:

[0028] Step 1: providing groundwater, wherein the content of Mn(II) in the groundwater is 0.5 mg / L, and the content of sulfamethoxazole is 150 ng / L.

[0029] Step 2: According to the content of Mn(II) in step 1, the molar concentration ratio of Mn(II): tannic acid: sodium sulfite is 1:5:10, the dosage of tannic acid and sodium sulfite is determined, the groundwater, tannic acid and sodium sulfite are mixed to obtain a mixed solution, the pH of the mixed solution is adjusted to 6, the reaction time is continued for 20 minutes, and the reaction solution is filtered to obtain a filtrate and a filter residue. After the reaction is completed, the residual content of Mn(II) in the filtrate (filtered groundwater) is quantitatively detected by ICP-OES, and the content of sulfamethoxazole in the filtrate (filtered groundwater) is quantitatively detected by a high performance liquid chromatography device, and a comparative analysis is performed with the original groundwater to determine the removal rate of Mn(II) and sulfamethoxazole. The experimental results are shown in Table 1.

[0030] Embodiment 2:

[0031] The difference from Example 1 is that the pH of the mixed solution is adjusted to pH 5. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0032] Embodiment 3:

[0033] The difference from Example 1 is that the pH of the mixed solution is adjusted to pH 7. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0034] Embodiment 4:

[0035] The difference from Example 1 is that the reaction time in this example is 15 min. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0036] Embodiment 5:

[0037] The difference from Example 1 is that the reaction time in this example is 30 min. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0038] Embodiment 6:

[0039] Different from Example 1, the complexing agent in this example is gallic acid. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0040] Embodiment 7:

[0041] Different from Example 1, gallic acid was selected as the complexing agent. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0042] Embodiment 8:

[0043] Different from Example 1, the complexing agent is nitrilotriacetic acid. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0044] Embodiment 9:

[0045] Different from Example 1, the molar ratio of Mn(II): complexing agent: sodium sulfite is 1:2:10. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0046] Embodiment 10:

[0047] Different from Example 1, the molar ratio of Mn(II): complexing agent: sodium sulfite is 1:10:10. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0048] Embodiment 11:

[0049] Different from Example 1, the molar ratio of Mn(II): complexing agent: sodium sulfite is 1:5:2. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0050] Embodiment 12:

[0051] Different from Example 1, the molar ratio of Mn(II): complexing agent: sodium sulfite is 1:5:5. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0052] Embodiment 13:

[0053] Different from Example 1, the molar ratio of Mn(II): complexing agent: sodium sulfite is 1:5:20. The removal rates of Mn(II) and sulfamethoxazole after treatment are shown in Table 1 below.

[0054] Comparative Example 1:

[0055] Different from 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.

[0056] Comparative Example 2:

[0057] Different from 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.

[0058] Table 1

[0059]

[0060]

[0061] As can be seen from the above table, from Examples 1-3, it can be seen that pH affects the removal rate of Mn(II) and sulfamethoxazole in the present invention. The present invention has a better removal effect on sulfamethoxazole under the condition of pH=6. A lower pH will affect the conversion of MnO2 in the reaction system and inhibit the removal of Mn(II). A higher pH will affect the formation and stability of active species in the reaction system, thereby having a poor removal effect on sulfamethoxazole. The treatment effect is best when pH=6.

[0062] It can be seen from Examples 1, 4, and 5 that the reaction time of the system affects the removal effect. When the reaction time is 20 min, not only is there a better removal rate, but also time cost can be saved. If the reaction time is insufficient, the active species cannot effectively remove the organic pollutants, and the conversion rate of MnO2 is low, and the adsorption capacity for Mn(II) is also insufficient.

[0063] It can be seen from Examples 1, 6, 7 and 8 that the removal effects of these four complexing agents on sulfamethoxazole and Mn(II) are similar, and each of the four has its own advantages.

[0064] As can be seen from Examples 1, 9-13, the molar ratio of Mn (II), complexing agent, and sodium sulfite has a certain influence on the removal rate of manganese and sulfamethoxazole. Wherein the molar ratio of Mn (II), complexing agent, and sodium sulfite is 1:5:10, and the effect is best. The low concentration of complexing agent can reduce the conversion and stability of active intermediates, thereby causing the overall reduction of the removal rate. The concentration of sodium sulfite is low, and the deficiency of HSO5-generation affects the occurrence of subsequent reactions. When the concentration of sodium sulfite is high, sodium sulfite will participate in the competition for HSO5- and active intermediates, resulting in poor removal effect.

[0065] It can be seen from Examples 1, 14-15 that in the absence of a complexing agent, Mn(II) cannot effectively activate sodium sulfite to generate HSO5 - , thus Mn(V) and MnO2 cannot be generated. Lack of sodium sulfite will result in HSO 3- , the subsequent reactions cannot proceed and the simultaneous removal of manganese and organic matter cannot be achieved.

[0066] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the 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: The following steps are involved: Provide a groundwater containing Mn(II) and organic contaminants; The chelating agent and sodium sulfite are added into the groundwater and mixed to obtain a mixed solution. The pH value of the mixed solution is adjusted to acidic or neutral, and the reaction is continued to achieve the simultaneous removal of manganese and organic pollutants in the groundwater.

2. The method according to claim 1, characterized in that The content of Mn(II) in the groundwater is 0.1 mg / L to 1 mg / L.

3. The method according to claim 1, characterized in that The content of organic pollutants in the groundwater is 100ng / L to 200ng / L.

4. The method according to claim 3, characterized in that The organic pollutants include antibiotics and endocrine disruptors.

5. The method according to claim 1, characterized in that The molar ratio of Mn(II) to the complexing agent in the groundwater is 1:2-1:10; the molar ratio of Mn(II) to sodium sulfite is 1:2-1:

20.

6. The method according to claim 1, characterized in that The sodium sulfite is selected from sodium sulfite and / or potassium sulfite.

7. The method according to claim 1, characterized in that The complexing agent is selected from one or more of tannic acid, gallic acid, gallic acid, nitrilotriacetic acid, citric acid, protocatechuic acid, vanillic acid, ethylenediaminetetraacetic acid, and 2-picolinic acid.

8. The method according to claim 1, characterized in that The reaction time is 15 min to 30 min.

9. The method according to claim 1, characterized in that: Adjust the pH value of the mixed solution to 5-7.

10. The method according to claim 9, characterized in that Adjust the pH value of the mixed solution to 5.5-6.

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