Composite functional material for wastewater denitrification treatment and preparation method and application thereof

Abstract

The application discloses a composite functional material for sewage denitrification treatment and a preparation method and application thereof. Raw materials of the composite functional material include pyrite, sulfur, sucrose and auxiliary components, wherein the mass ratio of the pyrite, the sulfur, the sucrose and the auxiliary components is 3-5:0.7-1.1:0.25-0.45:0.06-0.22. The composite functional material can efficiently remove nitrate in water bodies and is suitable for sewage treatment of different types.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of environmental engineering, and specifically belongs to a composite functional material for wastewater denitrification treatment and a preparation method and application thereof. BACKGROUND

[0002] Nitrate mainly comes from agricultural fertilization, industrial wastewater and domestic sewage. In water bodies, nitrate not only causes water bloom and water quality deterioration, but also can enter the human body through drinking water, causing health problems such as infantile cyanosis and gastric cancer. Therefore, how to effectively and economically remove nitrate in water has become an important issue in the field of environmental protection and public health.

[0003] At present, common nitrate removal technologies in water include physical methods, chemical methods and biological methods. Physical methods, such as reverse osmosis and ion exchange, have high removal efficiency, but the cost is high, and secondary pollution may be caused. Chemical methods, such as electrochemical reduction, are relatively simple to operate, but consume a lot of energy and are not suitable for large-scale application. Biological denitrification method is the most widely used technology at present, which uses microorganisms to reduce nitrate to nitrogen under anaerobic conditions, thereby achieving denitrification. However, this method is sensitive to environmental conditions, and the treatment efficiency is limited by the concentration of organic matter and temperature.

[0004] In view of the limitations of the prior art, it is particularly important to develop a new type of high-efficiency and low-cost nitrate removal material. SUMMARY

[0005] In order to solve the problems existing in the prior art, the present application provides a composite functional material for wastewater denitrification treatment and a preparation method and application thereof, which is mainly prepared from pyrite, sulfur and sucrose, and can efficiently remove nitrate in water, and is suitable for different types of wastewater treatment.

[0006] To achieve the above purpose, the present application provides the following technical scheme: a composite functional material for wastewater denitrification treatment, the raw materials of which include pyrite, sulfur, sucrose and auxiliary ingredients.

[0007] Further, the mass ratio of pyrite, sulfur, sucrose and auxiliary ingredients is 3-5:0.7-1.1:0.25-0.45:0.06-0.22.

[0008] Further, the auxiliary ingredients are quartz sand and activated carbon powder, and the particle size of the quartz sand is 100-200 mesh; the particle size of the activated carbon powder is 100-200 mesh.

[0009] The present application also provides a preparation method of a composite functional material for wastewater denitrification treatment, and the specific steps are as follows:

[0010] S1 mixes pyrite powder, sulfur powder, sucrose and auxiliary ingredients, and heats to obtain a melt;

[0011] S2 cools and shapes the melt to obtain a composite functional material.

[0012] Further, in S1, the heating is melting and mixing at a temperature of 120-200 DEG C for 25-40 minutes.

[0013] Further, in S2, the melt is poured into a mold for cooling and shaping to obtain a spherical composite functional material.

[0014] Further, in S2, the cooling temperature is lower than 119 DEG C.

[0015] Further, in S1, the particle size of the pyrite powder and the sulfur powder is 100-200 mesh.

[0016] The application also provides the use of the above-mentioned composite functional material for wastewater denitrification treatment or the composite functional material prepared by the above-mentioned preparation method for removing nitrate in water bodies.

[0017] Further, the water body includes groundwater, sewage plant sewage and urban rivers.

[0018] Compared with the prior art, the application has at least the following beneficial effects:

[0019] The application provides a composite functional material for wastewater denitrification treatment, which uses pyrite-sulfur-sucrose as raw materials, utilizes the strong reducing property of pyrite and the chemical stability of sulfur, combines sucrose and other filling materials, effectively improves the removal efficiency of nitrate under the premise of economy and environmental friendliness, and is expected to be widely used in industrial and civil water treatment fields.

[0020] The composite functional material of the application also effectively solves the defects of traditional denitrification technology, such as high cost, low efficiency and complex operation, and plays an important role in improving water quality safety, protecting public health and promoting ecological balance. Therefore, the pyrite-sulfur-sucrose composite functional material of the application provides a new perspective and solution for the removal of nitrate in water, and has important practical application value and broad market prospect.

[0021] The composite functional material has low material cost, avoids the problems of complex operation and high cost of traditional chemical and biological methods, has no secondary pollution, is easy to prepare, can significantly improve the nitrate removal rate in a short time, especially in groundwater, and is particularly prominent, which shows that the composite functional material can efficiently remove nitrate in water bodies, and is suitable for different types of water bodies, such as groundwater, sewage plant sewage and urban river, and has wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The nitrate removal efficiency diagram of the composite functional material for actual groundwater;

[0023] Figure 2 The nitrate removal efficiency diagram of the composite functional material for sewage plant sewage;

[0024] Figure 3 The nitrate removal efficiency diagram of the composite functional material for urban river sewage;

[0025] Figure 4 The effect diagram of the porosity of the composite functional material on the nitrate removal efficiency;

[0026] Figure 5 The preparation process of the composite functional material;

[0027] Figure 6 The entity diagram, electron microscope scanning diagram and entity diagram after use of the composite functional material before use. DETAILED DESCRIPTION

[0028] The application will be further described below in combination with the drawings and specific embodiments.

[0029] The application provides a composite functional material for sewage denitrification treatment, raw materials comprising: pyrite, sulfur, sucrose, quartz sand and activated carbon powder; wherein, the pyrite and sulfur are used as main denitrification components, the sucrose is used for forming pores at high temperature; and the quartz sand and activated carbon powder are used as auxiliary components to improve the mechanical strength and reaction efficiency of the material.

[0030] Preferably, the mass ratio of the pyrite, sulfur, sucrose and auxiliary components (quartz sand and activated carbon powder) is 3-5:0.7-1.1:0.25-0.45:0.06-0.22.

[0031] The prepared composite functional material is a porous spherical body with a diameter of 9-12 mm, and the weight of a single material is 2.8 g-2.1 g.

[0032] The application also provides a preparation method of the composite functional material for sewage denitrification treatment, and the specific steps are as follows:

[0033] S1 mixes the pyrite powder, sulfur powder, sucrose and auxiliary ingredients according to the above mass ratio to obtain a mixture.

[0034] S2 melts the mixture in an oil bath pot at a temperature of 120-200℃ for 25-40 minutes to obtain a melt;

[0035] S3 pours the melt into a mold to cool and shape, forming a spherical composite functional material with high mechanical strength, and the maximum specific surface area of the spherical composite functional material can improve the utilization rate of the material.

[0036] The present application utilizes the melting point characteristics of sulfur, which changes from solid to molten state at 120-200℃, and the foaming characteristics of sucrose at high temperature, mixes materials such as pyrite, and finally cools and shapes, so that the sucrose is fully mixed with the materials to form pores after foaming and breaking inside and outside the materials. After cooling below 119℃, the sulfur changes from molten state to solid state, thereby achieving the effect of material shaping, and also ensuring the mechanical strength of the material and the pore structure formed by the high-temperature foaming of sucrose.

[0037] Preferably, the particle size of the pyrite powder and the sulfur powder is 100-200 mesh; the particle size of the quartz sand is 100-200 mesh; the particle size of the activated carbon powder is 100-200 mesh;

[0038] Preferably, the particle size of the pyrite powder and the sulfur powder is 120 mesh; the particle size of the quartz sand is 120 mesh; the particle size of the activated carbon powder is 200 mesh;

[0039] The quality of the prepared composite functional material after removing nitrate is detected according to the standard GB / T 7314-2017, and the results are as follows:

[0040]

[0041] The calculated average compressive strength is 264.20 MPa. The minimum compressive strength value is 254.65 MPa, and the maximum value is 273.76 MPa. This fluctuation range (19.11 MPa) indicates that although all the test samples show similar compressive strength, there is still a certain degree of variation. This variation may be caused by the difference in microstructure of the sample, slight changes in test conditions or the inherent heterogeneity of the material. However, considering the average compressive strength and the fluctuation range, it can be concluded that the material shows good compressive performance under the test conditions. If these values meet the expectations of the sewage treatment application scenario, it can be considered that the material is suitable for the application of sewage treatment denitrification.

[0042] The composite functional material prepared above is suitable for removing nitrate in water bodies of different sources such as underground water, sewage of sewage plants and urban rivers. The composite functional material is put into a plastic tennis ball, and the amount of the composite functional material is determined according to the pool volume and the concentration of nitrate of the water body to be treated.

[0043] The concentration of nitrate is 100 mg / L, the pool volume is 100 m 3 , the amount of the composite functional material is 200 kg, and the removal rate can reach at least 95%, which is easy to be applied on a large scale.

[0044] The composite functional material provides an electron donor for microorganisms in water after being put into the water body, and is not easy to fall off, so there is basically no need to worry about the problem of material loss. Even if it falls off, it can still continue to play a role. The reaction is that pyrite (FeS2) reacts with nitrate (NO3 - ) to produce nitrite (NO2 - ), nitrogen (N2), sulfate (SO4 2- ) and iron ions (Fe 2+ ). The reaction equation is as follows:

[0045] 5FeS2+14NO3 - +4H2O→7N2+5SO4 2- +10Fe 2+ +16OH -

[0046] Sulfur (S) reacts with nitrate (NO3 - ) to produce nitrite (NO2 - ), nitrogen (N2) and sulfate (SO4 2 ). The reaction equation is as follows:

[0047] S+2NO3 - +2H2O→2N2+SO4 2- +4H +

[0048] It can be seen that the composite functional material of the present application can work effectively at natural room temperature, pH value of 6-7, without controlling dissolved oxygen.

[0049] Example 1

[0050] As shown in Figure 5 , a preparation method of a composite functional material for denitrification treatment of sewage, the specific steps are as follows:

[0051] S1: Mix pyrite powder, sulfur powder, sucrose and auxiliary ingredients in a mass ratio of 4:0.9:0.35:0.14 to obtain a mixture; the auxiliary ingredients are quartz sand and activated carbon powder;

[0052] S2 melt the mixture in an oil bath pot at a temperature of 140°C for 25 minutes to obtain a melt;

[0053] S3 pour the melt into a mold and cool to 60°C to shape, to form a composite functional material with high mechanical strength.

[0054] The composite functional material prepared in Example 1 was used to remove nitrate in actual groundwater, sewage plant sewage, and urban river sewage, and the efficiency of the composite functional material prepared in Example 1 in removing nitrate in water bodies of different sources was detected, as follows:

[0055] Control group setting: three control experiments do not add new materials, as a benchmark comparison.

[0056] Experimental group setting: three experiments each add 200 grams of the composite functional material prepared in Example 1 to 4 liters of water (sewage and sludge ratio 5:1).

[0057] Water source:

[0058] R0: blank control group (including three blank control groups, using actual groundwater, sewage plant sewage, and urban river sewage as blank controls, respectively)

[0059] R1: actual groundwater (nitrate concentration 25 mg / L).

[0060] R2: sewage plant sewage (nitrate concentration 57 mg / L).

[0061] R3: urban river sewage (nitrate concentration 17 mg / L).

[0062] Environmental conditions: pH 6-7, at room temperature, without special control of dissolved oxygen.

[0063] Experimental results

[0064] As shown in Table 1, the nitrate removal efficiency: Figures 1-4

[0065] Groundwater: the nitrate removal rate reached 100% when the residence time in water was 4.05 hours.

[0066] Sewage plant sewage: the removal rate reached more than 90% under the same residence time.

[0067] Urban river sewage: the removal rate also exceeded 90%.

[0068] Comparison: compared with the corresponding blank control group, respectively, the removal efficiency of nitrate was increased by about 70% after using the composite functional material of the application.

[0069] At the same time, as shown in Table 1, the nitrate removal efficiency: Figure 4 ​As shown, R0 is a composite material without pores, and R1 is a composite functional material with pores; through a continuous operation test for 130 consecutive days, it is shown that the presence or absence of pores in the composite material has a significant impact on the removal of nitrate, the nitrate removal rate of R1 is 71.4%, the nitrate removal rate of R0 is 30.4%, and the nitrate removal rate of R1 is nearly 40% higher than that of R0. Because the material has pores, the specific surface area of the material in contact with microorganisms can be increased, thereby shortening the removal time of nitrate, and at the same time, the increase in porosity also reduces the formation time of the microbial membrane, and the composite material without adding sucrose, that is, the composite material without pores, can also have a certain effect on the removal of nitrate, but its removal efficiency is not as high as that of the composite functional material with pores added with sucrose.

[0070] In summary, it can be seen that the composite functional material of the present application has excellent nitrate removal capability in different sources of water bodies (including groundwater, sewage plant sewage, urban river sewage), especially in groundwater, the composite functional material of the present application can completely remove nitrate in only 4.05 hours of hydraulic retention time, showing its rapid reaction characteristics.

[0071] Example 2

[0072] A preparation method of a composite functional material for sewage denitrification treatment, the specific steps are as follows:

[0073] S1, pyrite powder, sulfur powder, sucrose and auxiliary ingredients are mixed in a mass ratio of 3:1.1:0.45:0.22 to obtain a mixture; the auxiliary ingredients are quartz sand and activated carbon powder;

[0074] S2, the mixture is placed in an oil bath pot and melted at a temperature of 200 DEG C for 30 minutes to obtain a melt;

[0075] S3, the melt is poured into a mold and cooled and shaped to form a spherical composite functional material with high mechanical strength.

[0076] Example 3

[0077] A preparation method of a composite functional material for sewage denitrification treatment, the specific steps are as follows:

[0078] S1, pyrite powder, sulfur powder, sucrose and auxiliary ingredients are mixed in a mass ratio of 3:1.1:0.45:0.22 to obtain a mixture; the auxiliary ingredients are quartz sand and activated carbon powder;

[0079] S2, the mixture is placed in an oil bath pot and melted at a temperature of 200 DEG C for 30 minutes to obtain a melt;

[0080] S3, the melt is poured into a mold and cooled and shaped to form a spherical composite functional material with high mechanical strength.

[0081] Figure 6 For the composite functional material of the present application, entity graph, electron microscope scanning graph and entity graph after use are used, wherein Figure 6 a shows the material after molding treatment. The graph clearly shows that the material has spherical structure, rough surface and porous properties. These features are important for the attachment and utilization of microorganisms. Figure 6 b shows the surface microstructure of the same material by scanning electron microscope (SEM) technology. This graph reveals the roughness of the material surface, which further confirms its adsorption capacity for microorganisms. Figure 6 c is the state of the material after being used in water body for 120 days. From the graph, it can be observed that a thick biofilm has formed on the surface of the material, which indicates that microorganisms can effectively attach to the surface of the material and utilize the electrons provided by the material to carry out redox reactions, thereby removing nitrate in water. Figure 6 d uses scanning electron microscope technology to observe Figure 6 the surface of the material in c, which clearly shows the formation of biofilm. This observation directly proves the ability of the material to provide electrons for microorganisms in water body, thereby effectively removing nitrate in water.

[0082] The composite functional material of the present application is not only environmentally friendly but also cost-effective, with economic advantages in practical applications. Its application scenarios are wide, including but not limited to sewage treatment, groundwater treatment, household life and ecological water body improvement, etc. The development and application of this material provide a new and effective solution for sewage treatment and environmental remediation.

[0083] The present application not only highlights the technological innovation and environmental value of new materials, but also provides new ideas and methods for future research and application in related fields. Overall, the development of this material has important scientific significance and broad application prospects, marking an important progress in the field of environmental pollution control and resource recycling.

Claims

1. A composite functional material for wastewater denitrification treatment, characterized in that, The raw materials include pyrite, sulfur, sucrose and auxiliary ingredients; the mass ratio of pyrite, sulfur, sucrose and auxiliary ingredients is 3-5:0.7-1.1:0.25-0.45:0.06-0.22; The auxiliary ingredients are quartz sand and activated carbon powder, the particle size of the quartz sand is 100-200 meshes; the particle size of the activated carbon powder is 100-200 meshes; The preparation method of the composite functional material for sewage denitrification treatment comprises the following specific steps: S1: mixing pyrite powder, sulfur powder, sucrose and auxiliary ingredients and heating to obtain a melt; S2: cooling and shaping the melt to obtain the composite functional material; In S1, the heating is melting the mixture at a temperature of 120-200 DEG C for 25-40 minutes. 2.The composite functional material for denitrification treatment of sewage according to claim 1, characterized in that, In S2, the melt is poured into a mold for cooling and shaping to obtain the spherical composite functional material. 3.The composite functional material for denitrification treatment of sewage according to claim 1, characterized in that, In S2, the cooling temperature is lower than 119 DEG C. 4.The composite functional material for denitrification treatment of sewage according to claim 1, characterized in that, In S1, the particle size of the pyrite powder and the sulfur powder is 100-200 meshes.

5. The use of the composite functional material for sewage denitrification treatment according to any one of claims 1-4 in removing nitrate in water bodies.

6. Use according to claim 5, characterized in that, The water bodies include groundwater, sewage plant sewage and urban rivers.

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