Manganese removal method based on synergistic activation of molecular oxygen by potassium permanganate and calcium sulfite

Abstract

The invention discloses a manganese removal method based on potassium permanganate and calcium sulfite synergistic activation molecular oxygen, and belongs to the technical field of water treatment. The method comprises the following steps: firstly, adding potassium permanganate into manganese-containing water for preliminary oxidation, then adding calcium sulfite with slow release performance, reacting sulfite ions slowly and continuously released by the calcium sulfite with dissolved oxygen in the water to generate sulfate free radicals, oxidizing the residual divalent manganese into manganese dioxide, and filtering and removing the manganese dioxide through coagulating sedimentation. According to the method, the dosage of potassium permanganate is reduced through free radical reaction of calcium sulfite, and potassium permanganate is reduced when the potassium permanganate is excessive, so that the problem of effluent chromaticity is avoided; in addition, the final product calcium sulfate oxidized by calcium sulfite has a coagulation aiding effect, is beneficial to instability and precipitation of manganese dioxide, and guarantees the manganese removal effect. The method is high in manganese removal efficiency, stable in operation and low in cost, is slightly influenced by the fluctuation of the manganese concentration of the inlet water, solves the problems that the dosage is difficult to control and the chromaticity is easy to exceed the standard in the traditional process, and is favorable for guaranteeing the water quality safety of supplied water.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology and relates to a method for removing divalent manganese ions from water. In particular, it relates to a process method that utilizes the synergistic redox system of potassium permanganate and calcium sulfite to remove excess manganese ions from water and effectively control the color of the effluent. It is particularly suitable for water treatment fields such as drinking water and industrial water. Specifically, it is a manganese removal method based on the synergistic activation of molecular oxygen by potassium permanganate and calcium sulfite. Background Technology

[0002] Manganese is a transition metal element widely distributed in the Earth's crust and an essential trace element for human metabolism. However, excessive manganese intake can harm human health, especially long-term excessive intake which may cause chronic damage to the nervous system. Excessive manganese concentration in water is one of the important ways the public ingests excessive manganese. Excessive manganese not only leads to the deterioration of water quality's sensory properties, such as the formation of "yellow water," and even the production of black sediment, but it can also deposit scale on water pipes and filter media, thus interfering with the normal operation of water treatment processes. Therefore, developing efficient and reliable manganese removal technologies is of great significance for ensuring drinking water safety.

[0003] Currently, the main technologies for removing divalent manganese from water include: Aeration filtration: This method involves aerating manganese-containing water and then allowing the water to flow through a manganese sand filter media layer. Over long-term operation, a manganese-based active filter membrane naturally forms on the surface of the media. This membrane catalyzes the oxidation of divalent manganese in the water to manganese dioxide, which is then removed. However, this method has a slow start-up time, is sensitive to water quality conditions such as pH and iron content, and the filter membrane is prone to permeation under high manganese loads.

[0004] Direct oxidation method: This method involves adding strong oxidants such as chlorine, potassium permanganate, or ozone to oxidize divalent manganese to manganese dioxide, which is then removed through solid-liquid separation. Among these methods, potassium permanganate is the most widely used pre-oxidation manganese removal process due to its moderate oxidation potential, wide pH range adaptability, and the formation of dense manganese dioxide flocs as reaction products. However, this technology has the following limitations: the dosage must be precisely matched to the transient manganese concentration in the water. Insufficient dosage will lead to incomplete manganese removal; excessive dosage will not only waste reagents but also cause color problems in the effluent due to residual potassium permanganate.

[0005] Therefore, developing a manganese removal technology that can adapt to fluctuations in manganese concentration, leaves no color residue, and is cost-effective and efficient is of great practical significance for improving the operational stability of waterworks, ensuring water quality safety, and controlling treatment costs. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing oxidation manganese removal technologies, such as difficulty in controlling the dosage of oxidant, easy secondary color pollution, and high operating costs, and to provide a highly efficient, stable, and economical manganese removal method based on the synergistic effect of potassium permanganate and calcium sulfite.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A manganese removal method based on the synergistic effect of potassium permanganate and calcium sulfite includes the following steps: S1. Add potassium permanganate to water containing divalent manganese and react for 1 minute to ensure that the primary oxidation reaction between potassium permanganate and divalent manganese is basically completed; the initial concentration of divalent manganese ions in the water is 0.15-2 mg / L, and the mass ratio of potassium permanganate dosage to the concentration of divalent manganese ions in the water sample is 1:1 to 1.5:1.

[0008] S2. Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the amount of calcium sulfite added is 10-15 mg / L.

[0009] S3. After 30 seconds, 15 mg / L of coagulant was added to the water sample containing calcium sulfite for coagulation and sedimentation treatment, and then the generated manganese dioxide was further separated and removed by filtration.

[0010] The reactions in steps S1 and S2 are both carried out under stirring conditions at a stirring speed of 400 r / min.

[0011] The coagulation and sedimentation treatment in step S3 is divided into the following segments: Segment 01, duration 30 seconds, rotation speed 400 r / min; Segment 02, duration 1 minute, rotation speed 300 r / min; Segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; Segment 04, duration 11 minutes, rotation speed 100 r / min; Segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; Segment 06, duration 30 seconds, rotation speed 0 r / min.

[0012] The coagulant in step S3 is polyaluminum chloride, polyferric sulfate, or polyaluminum ferric chloride.

[0013] The potassium permanganate, calcium sulfite, and coagulant are all pre-dissolved stock solutions, and the solvent used is distilled water or tap water.

[0014] The synergistic effect mechanism of the method of this invention is as follows: 1. When the concentration of divalent manganese in the water is high, potassium permanganate first oxidizes part of the divalent manganese to generate manganese dioxide. Manganese dioxide catalyzes the reaction of sulfite ions with dissolved oxygen. During this oxidation process, sulfate free radicals are generated, which further oxidize the remaining divalent manganese to manganese dioxide; 2. When the concentration of divalent manganese in the raw water is low, the sulfite ions slowly released by calcium sulfite can reduce the residual potassium permanganate in the water, avoiding the color problem of the effluent caused by the residual potassium permanganate; 3. The concentration of sulfite ions has an important impact on the enhancement of potassium permanganate manganese removal. The sulfate free radicals generated during the reaction of low-concentration sulfite ions with dissolved oxygen are conducive to the conversion of divalent manganese to manganese dioxide, while high-concentration sulfite ions reduce the sulfate free radicals generated in situ, resulting in the inability to exert the oxidation effect; 4. Enhanced co-precipitation: The manganese dioxide generated by the two dosings both act as excellent coagulant aids, which can enhance the formation and sedimentation performance of flocs in the subsequent solid-liquid separation process; 5. The final product of the calcium sulfite reaction is slightly soluble calcium sulfate, which has a coagulant aid effect.

[0015] Compared with the prior art, the present invention has the following outstanding advantages: The calcium sulfite mentioned in step S2 is a chemical agent with sulfite ions as the main component. Calcium sulfite can slowly release sulfite ions, avoiding the reduction of manganese dioxide generated by sulfite ions due to excessively high local instantaneous concentration of sulfite ions, thus ensuring the manganese removal effect. Stable treatment effect and strong resistance to shock load: Within a wide range of influent manganese concentration (0.15~2 mg / L), the addition of potassium permanganate at a mass ratio of 1:1 and calcium sulfite at a mass ratio of 10~15 mg / L can achieve stable compliance of effluent manganese, without relying on expensive online monitoring and real-time feedback control systems, thus simplifying operation and management. Solving the problem of excessive effluent color: By using calcium sulfite to directionally reduce residual potassium permanganate, the problem of excessive effluent color caused by excessive oxidant is fundamentally avoided; Significantly reduces reagent costs and overall operating expenses: Thanks to the introduction of calcium sulfite and its synergistic oxidation effect of free radicals, the amount of potassium permanganate used can be reduced by 40% to 60%. At the same time, since no additional decolorization unit is required, it saves on equipment investment and operating energy consumption. The method is highly adaptable to the process and easy to implement: It can be directly embedded into various existing water treatment processes. Only two simple chemical dosing points need to be added in appropriate locations (such as distribution wells, mixing tanks, etc.). It requires little modification to existing facilities, has low investment costs, and is easy to promote and apply in water plants. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of the method of the present invention; Figure 2The graph shows the effect of potassium permanganate dosage on the total manganese removal efficiency in Examples 1-3. The water samples used were all reservoir water from Example 1, with an initial total manganese concentration of 0.8 mg / L. Figure 3 The graphs show the total manganese removal effect of water samples with different initial manganese concentrations when the mass ratio of potassium permanganate dosage to initial manganese content is 1:1 in Examples 4-7. Figure 4 The diagrams show the effect of the present invention on the removal of total manganese from reservoir water when polyaluminum chloride, polyferric sulfate, and polyaluminum ferric sulfate are used as coagulants in Examples 1, 8, and 9, respectively. Detailed Implementation

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0018] Example 1 The manganese concentration in the reservoir of a certain water plant is 0.8 mg / L, the pH is 6.5-7.0, and the water temperature is 12 ℃.

[0019] Processing steps: Step 1: Take 500 ml of manganese-containing reservoir water, add potassium permanganate at a dosage of 0.8 mg / L, and react for 1 minute.

[0020] Step 2: Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the dosage of calcium sulfite is 10 mg / L.

[0021] Step 3: After 30 seconds, add 15 mg / L polyaluminum chloride to the water sample for coagulation and sedimentation treatment, and then further separate and remove the generated manganese dioxide by filtration.

[0022] The reactions in steps 1 and 2 are both carried out under stirring at a speed of 400 r / min.

[0023] The coagulation and sedimentation process in step 3 is divided into the following segments: Segment 01, duration 30 seconds, rotation speed 400 r / min; Segment 02, duration 1 minute, rotation speed 300 r / min; Segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; Segment 04, duration 11 minutes, rotation speed 100 r / min; Segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; Segment 06, duration 30 seconds, rotation speed 0 r / min.

[0024] The potassium permanganate, calcium sulfite, and polyaluminum chloride mentioned above are all pre-dissolved stock solutions in distilled water or tap water.

[0025] Test results: The total manganese concentration in the effluent was 0.044 mg / L, and there was no pink color.

[0026] Example 2 The manganese concentration in the reservoir of a certain water plant is 0.8 mg / L, the pH is 6.5-7.0, and the water temperature is 12 ℃.

[0027] Processing steps: Step 1: Take 500 ml of manganese-containing reservoir water, add potassium permanganate at a dosage of 1.0 mg / L, and react for 1 minute.

[0028] Step 2: Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the dosage of calcium sulfite is 10 mg / L.

[0029] Step 3: After 30 seconds, add 15 mg / L polyaluminum chloride to the water sample for coagulation and sedimentation treatment, and then further separate and remove the generated manganese dioxide by filtration.

[0030] The reactions in steps 1 and 2 are both carried out under stirring at a speed of 400 r / min.

[0031] The coagulation and sedimentation treatment in step 3 is divided into the following segments: segment 01, duration 30 seconds, rotation speed 400 r / min; segment 02, duration 1 minute, rotation speed 300 r / min; segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; segment 04, duration 11 minutes, rotation speed 100 r / min; segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; segment 06, duration 30 seconds, rotation speed 0 r / min.

[0032] The potassium permanganate, calcium sulfite, and polyaluminum chloride mentioned above are all pre-dissolved stock solutions in distilled water or tap water.

[0033] Test results: The total manganese concentration in the effluent was 0.005 mg / L, which is below the national drinking water standard limit, and there was no pink color.

[0034] Example 3 The manganese concentration in the reservoir of a certain water plant is 0.8 mg / L, the pH is 6.5-7.0, and the water temperature is 12 ℃.

[0035] Processing steps: Step 1: Take 500 ml of manganese-containing reservoir water, add potassium permanganate at a dosage of 1.2 mg / L, and react for 1 minute.

[0036] Step 2: Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the dosage of calcium sulfite is 10 mg / L.

[0037] Step 3: After 30 seconds, add 15 mg / L polyaluminum chloride to the water sample for coagulation and sedimentation treatment, and then further separate and remove the generated manganese dioxide by filtration.

[0038] The reactions in steps 1 and 2 are both carried out under stirring at a speed of 400 r / min.

[0039] The coagulation and sedimentation treatment in step 3 is divided into the following segments: segment 01, duration 30 seconds, rotation speed 400 r / min; segment 02, duration 1 minute, rotation speed 300 r / min; segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; segment 04, duration 11 minutes, rotation speed 100 r / min; segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; segment 06, duration 30 seconds, rotation speed 0 r / min.

[0040] The potassium permanganate, calcium sulfite, and polyaluminum chloride mentioned above are all pre-dissolved stock solutions in distilled water or tap water.

[0041] Test results: No manganese was detected in the effluent, meeting the national drinking water standards, and there was no pink color.

[0042] Example 4 The manganese concentration in the reservoir of a certain water plant is 0.15 mg / L, the pH is 6.5-7.0, and the water temperature is 12 ℃.

[0043] Processing steps: Step 1: Take 500 ml of manganese-containing reservoir water, add potassium permanganate at a dosage of 0.15 mg / L, and react for 1 minute.

[0044] Step 2: Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the dosage of calcium sulfite is 10 mg / L.

[0045] Step 3: After 30 seconds, add 15 mg / L polyaluminum chloride to the water sample for coagulation and sedimentation treatment, and then further separate and remove the generated manganese dioxide by filtration.

[0046] The reactions in steps 1 and 2 are both carried out under stirring at a speed of 400 r / min.

[0047] The coagulation and sedimentation treatment in step 3 is divided into the following segments: segment 01, duration 30 seconds, rotation speed 400 r / min; segment 02, duration 1 minute, rotation speed 300 r / min; segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; segment 04, duration 11 minutes, rotation speed 100 r / min; segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; segment 06, duration 30 seconds, rotation speed 0 r / min.

[0048] The potassium permanganate, calcium sulfite, and polyaluminum chloride mentioned above are all pre-dissolved stock solutions in distilled water or tap water.

[0049] Test results: No manganese was detected in the effluent, meeting the national drinking water standards, and there was no pink color.

[0050] Example 5 The manganese concentration in the reservoir of a certain water plant is 1.0 mg / L, the pH is 6.5-7.0, and the water temperature is 12 ℃.

[0051] Processing steps: Step 1: Take 500 ml of manganese-containing reservoir water, add potassium permanganate at a dosage of 1.0 mg / L, and react for 1 minute.

[0052] Step 2: Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the dosage of calcium sulfite is 10 mg / L.

[0053] Step 3: After 30 seconds, add 15 mg / L polyaluminum chloride to the water sample for coagulation and sedimentation treatment, and then further separate and remove the generated manganese dioxide by filtration.

[0054] The reactions in steps 1 and 2 are both carried out under stirring at a speed of 400 r / min.

[0055] The coagulation and sedimentation treatment in step 3 is divided into the following segments: segment 01, duration 30 seconds, rotation speed 400 r / min; segment 02, duration 1 minute, rotation speed 300 r / min; segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; segment 04, duration 11 minutes, rotation speed 100 r / min; segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; segment 06, duration 30 seconds, rotation speed 0 r / min.

[0056] The potassium permanganate, calcium sulfite, and polyaluminum chloride mentioned above are all pre-dissolved stock solutions in distilled water or tap water.

[0057] Test results: The total manganese concentration in the effluent was 0.028 mg / L, and there was no pink color.

[0058] Example 6 The manganese concentration in the reservoir of a certain water plant is 1.5 mg / L, the pH is 6.5-7.0, and the water temperature is 12 ℃.

[0059] Processing steps: Step 1: Take 500 ml of manganese-containing reservoir water, add potassium permanganate at a dosage of 1.5 mg / L, and react for 1 minute.

[0060] Step 2: Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the dosage of calcium sulfite is 15 mg / L.

[0061] Step 3: After 30 seconds, add 15 mg / L polyaluminum chloride to the water sample for coagulation and sedimentation treatment, and then further separate and remove the generated manganese dioxide by filtration.

[0062] The reactions in steps 1 and 2 are both carried out under stirring at a speed of 400 r / min.

[0063] The coagulation and sedimentation treatment in step 3 is divided into the following segments: segment 01, duration 30 seconds, rotation speed 400 r / min; segment 02, duration 1 minute, rotation speed 300 r / min; segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; segment 04, duration 11 minutes, rotation speed 100 r / min; segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; segment 06, duration 30 seconds, rotation speed 0 r / min.

[0064] The potassium permanganate, calcium sulfite, and polyaluminum chloride mentioned above are all pre-dissolved stock solutions in distilled water or tap water.

[0065] Test results: The total manganese concentration in the effluent was 0.046 mg / L, and there was no pink color.

[0066] Example 7 The manganese concentration in the reservoir of a certain water plant is 2.0 mg / L, the pH is 6.5-7.0, and the water temperature is 12 ℃.

[0067] Processing steps: Step 1: Take 500 ml of manganese-containing reservoir water, add potassium permanganate at a dosage of 2.0 mg / L, and react for 1 minute.

[0068] Step 2: Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the dosage of calcium sulfite is 15 mg / L.

[0069] Step 3: After 30 seconds, add 15 mg / L polyaluminum chloride to the water sample for coagulation and sedimentation treatment, and then further separate and remove the generated manganese dioxide by filtration.

[0070] The reactions in steps 1 and 2 are both carried out under stirring at a speed of 400 r / min.

[0071] The coagulation and sedimentation treatment in step 3 is divided into the following segments: segment 01, duration 30 seconds, rotation speed 400 r / min; segment 02, duration 1 minute, rotation speed 300 r / min; segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; segment 04, duration 11 minutes, rotation speed 100 r / min; segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; segment 06, duration 30 seconds, rotation speed 0 r / min.

[0072] The potassium permanganate, calcium sulfite, and polyaluminum chloride mentioned above are all pre-dissolved stock solutions in distilled water or tap water.

[0073] Test results: The total manganese concentration in the effluent was 0.082 mg / L, and there was no pink color.

[0074] Example 8 The manganese concentration in the reservoir of a certain water plant is 2 mg / L, the pH is 6.5-7.0, and the water temperature is 12 ℃.

[0075] Processing steps: Step 1: Take 500 ml of manganese-containing reservoir water, add potassium permanganate at a dosage of 3 mg / L, and react for 1 minute.

[0076] Step 2: Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the dosage of calcium sulfite is 15 mg / L.

[0077] Step 3: After 30 seconds, add 15 mg / L polyferric sulfate to the water sample for coagulation and sedimentation treatment, and then further separate and remove the generated manganese dioxide by filtration.

[0078] The reactions in steps 1 and 2 are both carried out under stirring at a speed of 400 r / min.

[0079] The coagulation and sedimentation treatment in step 3 is divided into the following segments: segment 01, duration 30 seconds, rotation speed 400 r / min; segment 02, duration 1 minute, rotation speed 300 r / min; segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; segment 04, duration 11 minutes, rotation speed 100 r / min; segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; segment 06, duration 30 seconds, rotation speed 0 r / min.

[0080] The potassium permanganate, calcium sulfite, and polyaluminum chloride mentioned above are all pre-dissolved stock solutions in distilled water or tap water.

[0081] Test results: The total manganese concentration in the effluent was 0.053 mg / L, and there was no pink color.

[0082] Example 9 The manganese concentration in the reservoir of a certain water plant is 2 mg / L, the pH is 6.5-7.0, and the water temperature is 12 ℃.

[0083] Processing steps: Step 1: Take 500 ml of manganese-containing reservoir water, add potassium permanganate at a dosage of 3 mg / L, and react for 1 minute.

[0084] Step 2: Then, calcium sulfite is added to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; the dosage of calcium sulfite is 15 mg / L.

[0085] Step 3: After 30 seconds, add 15 mg / L of polyaluminum iron to the water sample for coagulation and sedimentation treatment, and then further separate and remove the generated manganese dioxide by filtration.

[0086] The reactions in steps 1 and 2 are both carried out under stirring at a speed of 400 r / min.

[0087] The coagulation and sedimentation treatment in step 3 is divided into the following segments: segment 01, duration 30 seconds, rotation speed 400 r / min; segment 02, duration 1 minute, rotation speed 300 r / min; segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; segment 04, duration 11 minutes, rotation speed 100 r / min; segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; segment 06, duration 30 seconds, rotation speed 0 r / min.

[0088] The potassium permanganate, calcium sulfite, and polyaluminum chloride mentioned above are all pre-dissolved stock solutions in distilled water or tap water.

[0089] Test results: The total manganese concentration in the effluent was 0.061 mg / L, and there was no pink color.

Claims

1. A method for removing manganese based on the synergistic activation of molecular oxygen by potassium permanganate and calcium sulfite, comprising the following steps: S1. Add potassium permanganate to water containing divalent manganese, wherein the mass ratio of potassium permanganate added to the concentration of divalent manganese ions in the water sample is 1:1 to 1.5:1, and react for 1 minute; S2. Then add 10-15 mg / L calcium sulfite to the water to continuously release sulfite ions, which react with dissolved oxygen in the water to generate highly reactive sulfate free radicals; S3. After 30 seconds, 15 mg / L of coagulant was added to the water sample containing calcium sulfite for coagulation and sedimentation treatment, and then the generated manganese dioxide was further separated and removed by filtration.

2. The manganese removal method based on the synergistic activation of molecular oxygen by potassium permanganate and calcium sulfite according to claim 1, characterized in that, The initial concentration of divalent manganese ions in the water in step S1 is 0.15–2 mg / L.

3. The manganese removal method based on the synergistic activation of molecular oxygen by potassium permanganate and calcium sulfite according to claim 1, characterized in that, The reactions in steps S1 and S2 are both carried out under stirring conditions at a stirring speed of 400 r / min.

4. The manganese removal method based on the synergistic activation of molecular oxygen by potassium permanganate and calcium sulfite according to claim 1, characterized in that, The coagulation and sedimentation treatment in step S3 is divided into the following segments: Segment 01, duration 30 seconds, rotation speed 400 r / min; Segment 02, duration 1 minute, rotation speed 300 r / min; Segment 03, duration 5 minutes 30 seconds, rotation speed 150 r / min; Segment 04, duration 11 minutes, rotation speed 100 r / min; Segment 05, duration 5 minutes 30 seconds, rotation speed 60 r / min; Segment 06, duration 30 seconds, rotation speed 0 r / min.

5. The manganese removal method based on the synergistic activation of molecular oxygen by potassium permanganate and calcium sulfite according to claim 1, characterized in that, The coagulant in step S3 is polyaluminum chloride, polyferric sulfate, or polyaluminum ferric chloride.

6. The manganese removal method based on the synergistic activation of molecular oxygen by potassium permanganate and calcium sulfite according to claim 1, characterized in that, The potassium permanganate, calcium sulfite, and coagulant are all pre-dissolved stock solutions, and the solvent used is distilled water or tap water.

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