Method for removing manganese ions in sewage

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a method for removing manganese ions in sewage. The method for removing the manganese ions in the sewage comprises the following steps: adding sodium sulfide, a flocculating agent and magnetic powder into the manganese-containing sewage, mixing, and filtering. The method for removing the manganese ions in the sewage has the beneficial effects that the sodium sulfide is added into the sewage, so that the manganese ions and the sulfur ions in the sewage generate the manganese sulfide precipitate, the solubility of the manganese sulfide is far lower than that of other manganese compounds, and the magnetic powder is added in the flocculation process, so that the magnetic powder is mixed into the flocculating constituent, and the magnetic powder is separated from the flocculating constituent; the mass of the flocculating constituent is increased, the flocculating constituent is easier to settle, the solid-liquid separation efficiency is improved, and the final manganese ion removal rate can reach 99% or above.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sewage treatment, and particularly relates to a method for removing manganese ions in sewage. BACKGROUND

[0002] Manganese-containing wastewater entering the environment can pollute soil and groundwater and affect the growth and development of animals and plants. Excessive manganese intake can cause animal and plant poisoning and destroy the ecological balance. Long-term drinking of water with excessive manganese can cause damage to the nervous system and may cause symptoms such as memory loss, emotional instability, insomnia, and headache.

[0003] Existing methods for treating manganese-containing wastewater include strong oxidant method, biological manganese removal method, and chemical precipitation method. The strong oxidant method oxidizes Mn 2+ into manganese dioxide and the like by adding strong oxidants such as potassium permanganate and chlorine, and then removes manganese in water through coagulation sedimentation and filtration. However, the use of strong oxidants can cause secondary pollution, and the operation is complex. The biological manganese removal method oxidizes Mn 2+ into manganese dioxide and the like by using the action of microorganisms, and then removes it through biological membrane filtration. However, the treatment effect of this method is greatly affected by the environment, and the treatment time is relatively long. The chemical precipitation method generates manganese carbonate precipitate by adjusting the pH value of wastewater, adding carbonates and flocculants, and then performing filtration treatment. However, this method requires precise control of the pH and reaction conditions of wastewater, and the treatment effect is affected by many factors. SUMMARY

[0004] The application provides a method for removing manganese ions in sewage, aiming to solve the problems of complex process, easy secondary pollution, and high cost of existing methods for removing manganese ions in sewage.

[0005] The application provides a method for removing manganese ions in sewage, which comprises the following steps: adding sodium sulfide, flocculants, and magnetic powder mixture into manganese-containing wastewater, and then filtering.

[0006] The method for removing manganese ions in sewage described in the application adds sodium sulfide into wastewater, so that manganese ions in the wastewater form manganese sulfide precipitate with sulfur ions. The solubility of manganese sulfide is much lower than that of other manganese compounds, and magnetic powder is added in the flocculation process to mix magnetic powder into the flocculation body. The mass of the flocculation body becomes larger, which is more easily settled, and the solid-liquid separation efficiency is improved. Finally, the removal rate of manganese ions can reach more than 99%.

[0007] According to some embodiments of the method for removing manganese ions in sewage described in the application, the content of manganese ions in the wastewater is ≥200 mg / L.

[0008] According to some embodiments of the method for removing manganese ions in sewage described in the application, the addition amount of sodium sulfide is 150-650 mg / L.

[0009] According to some embodiments of the method for removing manganese ions in sewage according to the application, the flocculant comprises one or more of polyacrylamide, polyaluminum chloride and polyferric sulfate.

[0010] According to some embodiments of the method for removing manganese ions in sewage according to the application, the flocculant is added in an amount of 50-250 mg / L.

[0011] According to some embodiments of the method for removing manganese ions in sewage according to the application, the magnetic powder comprises iron oxide magnetic powder and / or chromium dioxide magnetic powder.

[0012] According to some embodiments of the method for removing manganese ions in sewage according to the application, the magnetic powder is added in an amount of 500-2000 mg / L.

[0013] According to some embodiments of the method for removing manganese ions in sewage according to the application, the particle size of the magnetic powder is 0.1-0.3 mm.

[0014] According to some embodiments of the method for removing manganese ions in sewage according to the application, the temperature of the mixing is 20-30℃, and the mixing time is 5-10 min.

[0015] The beneficial effects of the application include: the method for removing manganese ions in sewage according to the application adds sodium sulfide into sewage, so that manganese ions in the sewage generate manganese sulfide precipitate with sulfur ions, because the solubility of manganese sulfide is much lower than that of other manganese compounds, and magnetic powder is added in the process of flocculation, so that the magnetic powder is mixed into the flocculation body, the mass of the flocculation body becomes larger, and it is easier to settle, the solid-liquid separation efficiency is improved, and finally the removal rate of manganese ions can reach more than 99%. DETAILED DESCRIPTION

[0016] The embodiments of the application are described in detail below, and the examples of the embodiments are exemplary and are intended to explain the application, and cannot be understood as a limitation of the application.

[0017] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the application. In the present specification, the illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0018] The method for removing manganese ions in sewage provided by the embodiments of the present application comprises the following steps: adding sodium sulfide, a flocculant and magnetic powder into manganese-containing sewage, and filtering.

[0019] The method for removing manganese ions in sewage provided by the embodiments of the present application adds sodium sulfide into sewage, so that manganese ions in the sewage react with sulfur ions to form manganese sulfide precipitate. Since the solubility of manganese sulfide is much lower than that of other manganese compounds, and magnetic powder is added in the flocculation process, the magnetic powder is mixed into the flocculation body, the mass of the flocculation body becomes larger, the flocculation body is more likely to settle, the solid-liquid separation efficiency is improved, and finally the removal rate of manganese ions can reach more than 99%.

[0020] In some embodiments of the present application, the content of manganese ions in the sewage is ≥200 mg / L, such as 200 mg / L, 250 mg / L, 280 mg / L, 320 mg / L, 360 mg / L, 430 mg / L, 500 mg / L, etc.

[0021] In some embodiments of the present application, the addition amount of sodium sulfide is 150-650 mg / L, such as 150 mg / L, 230 mg / L, 320 mg / L, 380 mg / L, 430 mg / L, 560 mg / L, 650 mg / L, etc. Controlling the addition amount of sodium sulfide in this range can make manganese ions in the sewage fully react with sulfur ions.

[0022] In some embodiments of the present application, the flocculant comprises one or more of polyacrylamide, polyaluminum chloride and polyferric sulfate.

[0023] The flocculant can promote the aggregation of suspended matter and colloidal particles in water to form flocculation body, thereby efficiently realizing solid-liquid separation.

[0024] In some embodiments of the present application, the addition amount of the flocculant is 50-250 mg / L, such as 50 mg / L, 120 mg / L, 180 mg / L, 220 mg / L, 250 mg / L, etc. The addition of the flocculant can make the suspended matter flocculate and precipitate quickly.

[0025] In some embodiments of the present application, the magnetic powder comprises iron oxide magnetic powder and / or chromium dioxide magnetic powder. Mixing the magnetic powder into the flocculation body can make the mass of the flocculation body larger, so that the flocculation body is more likely to settle and the solid-liquid separation efficiency is improved.

[0026] In some embodiments of the present application, the addition amount of the magnetic powder is 500-2000 mg / L, such as 500 mg / L, 800 mg / L, 1000 mg / L, 1200 mg / L, 1500 mg / L, 1800 mg / L, 2000 mg / L, etc.

[0027] In some embodiments of the present application, the particle size of the magnetic powder is 0.1-0.3mm, such as 0.1mm, 0.15mm, 0.20mm, 0.26mm, 0.30mm, etc.

[0028] In some embodiments of the present application, the temperature of the mixing is 20-30℃, such as 20℃, 22℃, 25℃, 28℃, 30℃, etc., and the time of the mixing is 5-10min, such as 5min, 6min, 8min, 10min, etc.

[0029] The technical solutions of the present application are further described below in combination with specific embodiments.

[0030] Embodiment 1

[0031] A method for removing manganese ions in sewage, comprising the following steps:

[0032] Sodium sulfide is added to manganese-containing sewage with a manganese content of 300mg / L at a dosage of 450mg / L, and then 50mg / L of polyacrylamide flocculant and 800mg / L of iron oxide magnetic powder with a particle size of 0.1mm are added to the sewage, which is mixed and stirred for 5min at a temperature of 25℃, and then filtered.

[0033] Embodiment 2

[0034] The difference between the method for removing manganese ions in sewage according to Embodiment 2 and Embodiment 1 is that the dosage of the magnetic powder in the method according to Embodiment 2 is 500mg / L.

[0035] The specific operation steps include:

[0036] Sodium sulfide is added to manganese-containing sewage with a manganese content of 300mg / L at a dosage of 450mg / L, and then 50mg / L of polyacrylamide flocculant and 500mg / L of iron oxide magnetic powder with a particle size of 0.1mm are added to the sewage, which is mixed and stirred for 5min at a temperature of 25℃, and then filtered.

[0037] Embodiment 3

[0038] The difference between the method for removing manganese ions in sewage according to Embodiment 3 and Embodiment 1 is that the dosage of the magnetic powder in the method according to Embodiment 3 is 1500mg / L.

[0039] The specific operation steps include:

[0040] The manganese content of the wastewater containing manganese is 300 mg / L, 450 mg / L of sodium sulfide is added to the wastewater containing manganese and mixed uniformly, then 50 mg / L of polyacrylamide flocculant and 1500 mg / L of iron oxide magnetic powder with a particle size of 0.1 mm are added to the wastewater, and the mixture is stirred for 5 min at a temperature of 25°C, and then filtered.

[0041] Example 4

[0042] The difference between the method for removing manganese ions in wastewater according to Example 4 and Example 1 is that the amount of magnetic powder added in the method according to Example 4 is 2000 mg / L.

[0043] The specific operation steps include:

[0044] The manganese content of the wastewater containing manganese is 300 mg / L, 450 mg / L of sodium sulfide is added to the wastewater containing manganese and mixed uniformly, then 50 mg / L of polyacrylamide flocculant and 2000 mg / L of iron oxide magnetic powder with a particle size of 0.1 mm are added to the wastewater, and the mixture is stirred for 5 min at a temperature of 25°C, and then filtered.

[0045] Comparative Example 1

[0046] The difference between the method for removing manganese ions in wastewater according to Comparative Example 1 and Example 1 is that no magnetic powder is added in the method according to Comparative Example 1.

[0047] The specific operation steps include:

[0048] The manganese content of the wastewater containing manganese is 300 mg / L, 450 mg / L of sodium sulfide is added to the wastewater containing manganese and mixed uniformly, then 50 mg / L of polyacrylamide flocculant and 2000 mg / L of iron oxide magnetic powder with a particle size of 0.1 mm are added to the wastewater, and the mixture is stirred for 5 min at a temperature of 25°C, and then filtered.

[0049] The effect of the methods for removing manganese ions in wastewater according to Examples 1-4 and Comparative Example 1 is studied, and the results are shown in Table 1.

[0050] Table 1

[0051] Sedimentation rate of suspended matter Sludge production Example 1 Fast Small amount Example 2 Slow Small amount Example 3 Very fast Large amount Example 4 Very fast Large amount Comparative example 1 Very slow Medium

[0052] As can be seen from Table 1, the addition of magnetic powder can promote the settling speed of suspended solids and reduce the amount of flocculant used. As the amount of magnetic powder added increases, the settling speed also increases, but the amount of sludge produced increases when the amount of magnetic powder added exceeds a certain amount. Although the settling speed of suspended solids is faster when the amount of magnetic powder added is 1-2 g / L, the amount of sludge produced is the least when the amount of magnetic powder added is 0.5-0.8 g / L, therefore, the optimal range of the amount of magnetic powder added is 0.8-1.0 g / L.

[0053] The method for removing manganese ions in sewage described in the present application can achieve a removal rate of manganese ions in sewage of 99% or more.

[0054] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limiting the present application, and any changes, modifications, replacements and variations made by those of ordinary skill in the art to the above embodiments are within the protection scope of the present application.

Claims

1. A method for removing manganese ions from sewage, characterized in that: The method comprises the following steps: adding sodium sulfide, flocculant and magnetic powder into manganese-containing wastewater, mixing the mixture and filtering the mixture.

2. The method for removing manganese ions from sewage according to claim 1, wherein The content of manganese ions in the sewage is ≥200 mg / L.

3. The method for removing manganese ions from sewage according to claim 1, wherein The amount of sodium sulfide added is 150-650 mg / L.

4. The method for removing manganese ions from sewage according to claim 1, wherein The flocculant includes one or more of polyacrylamide, polyaluminium chloride and polyferric sulfate.

5. The method for removing manganese ions from sewage according to claim 1, wherein The added amount of the flocculant is 50-250 mg / L.

6. The method for removing manganese ions from sewage according to claim 1, wherein The magnetic powder includes iron oxide magnetic powder and / or chromium dioxide magnetic powder.

7. The method for removing manganese ions from sewage according to claim 1, wherein The added amount of the magnetic powder is 500-2000 mg / L.

8. The method for removing manganese ions from sewage according to claim 1, wherein The particle size of the magnetic powder is 0.1-0.3 mm.

9. The method for removing manganese ions from sewage according to claim 1, wherein The mixing temperature is 20-30° C., and the mixing time is 5-10 minutes.