Nanomaterials prepared using manganese slag, methods and applications thereof

Abstract

The application discloses a nanometer material prepared from manganese slag and a preparation method and application thereof, and belongs to the technical field of environmental material preparation and application. The preparation method comprises the following steps: drying, crushing, ball milling and sieving manganese slag to obtain manganese slag powder A; dissolving the manganese slag powder A in a sulfuric acid solution, centrifuging and filtering to obtain a filtrate; adjusting the pH value of the filtrate and standing to obtain an iron-manganese-containing filtrate B; stirring the filtrate B and adjusting the pH value, filtering to obtain a ferric hydroxide filter residue, drying the ferric hydroxide filter residue to obtain solid ferric hydroxide particles, dissolving the solid ferric hydroxide particles in a hydrochloric acid solution to obtain a ferric chloride solution, adding nickel chloride hexahydrate to the ferric chloride solution to obtain a nickel-iron mixed solution C; preparing green tea extract D, dropping the green tea extract D into the solution C and standing to obtain an iron-nickel mixed suspension E; and after the iron-nickel mixed suspension E is extracted, washed and dried, nZVN-I@Fe2O3 with an Fe2O3 shell on the surface is obtained. The material has good stability and storage performance, can effectively activate persulfate to degrade antibiotics in water, and provides a new method for manganese slag resource utilization and antibiotic pollution treatment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of environmental material preparation and application, and particularly relates to a nanomaterial prepared from manganese slag and a method and application thereof. BACKGROUND

[0002] Antibiotics have been widely used in human production and life, and part of them have entered the environment. At present, antibiotics have become a typical new pollutant in the environment. The antibiotics in aquaculture wastewater, hospital wastewater and municipal wastewater have the problem of low treatment efficiency when treated by the current conventional biological method and chemical oxidation method.

[0003] Based on Fenton and persulfate (hereinafter referred to as PS), the advanced oxidation technology gradually attracts attention in the treatment of antibiotic wastewater due to its strong oxidation, but the oxidation efficiency needs to be further improved. The key way to improve the oxidation efficiency should be to improve the efficiency of free radicals generated by Fenton reagent or persulfate in the oxidation process. Therefore, how to efficiently activate PS has become one of the research hotspots in the treatment of antibiotic pollution.

[0004] PS can be activated by transition metals, and iron ions and zero-valent iron become the first choice of transition metal materials for activating PS due to their high activity, wide source and low price, especially nano zero-valent iron (hereinafter referred to as nZVI) can slowly release ferrous ions Fe 2+ , so as to prevent the generation of excessive Fe 2+ , SO4 - ˙ and OH - ˙ free radicals in a short time during the oxidation process, and nZVI can directly activate PS, which is a very ideal PS activator. However, nZVI is easy to agglomerate and be oxidized by oxygen in the air during storage and use, which affects its activity. SUMMARY

[0005] In view of the problems in the prior art that nZVI is easy to agglomerate and be oxidized by oxygen in the air during storage and use, which leads to a decrease in activity, these problems seriously affect the application efficiency and stability of nZVI in the treatment of antibiotic pollution. The present application provides a nanomaterial prepared from manganese slag and a method and application thereof, which aims to extract iron elements from manganese slag, a solid waste produced by wet smelting of manganese ore, in an open environment with oxygen by an innovative method, and use these iron elements to prepare nano zero-valent iron with a Fe2O3 shell covered on the surface by using green tea extract as a green reducing agent. The Fe2O3 shell can not only protect the Fe 0The organic components in the green tea extract can also play the role of dispersant and masking agent in the synthesis process of the material, thereby relieving the agglomeration of the nano zero-valent iron, and significantly improving the dispersibility and stability of the material. In addition, nickel is a transition non-noble metal, and because its 3d orbit is not filled, it can form a primary cell with the nano zero-valent iron material during the degradation of pollutants, thereby accelerating the electron transfer and reducing the reaction activation energy. In addition, the material can efficiently activate PS, and significantly improve the effect of degrading antibiotics in water. The experimental results show that when the material is used to activate PS to degrade antibiotics (such as norfloxacin) in water, the degradation efficiency can reach 99.82%, and after being stored in air for 45 days, the degradation efficiency can still reach 93.10%, which is significantly better than the nZVI material prepared by using sodium borohydride as a reducing agent and the nZVN-I material without Fe2O3 in the prior art. For example, the nZVI@Fe2O3 material prepared by the prior art has a degradation efficiency of 64.48% for norfloxacin, and the nZVN-I material has a degradation efficiency of norfloxacin decreased by 44.06% after being stored in air for 45 days, while the nZVN-I@Fe2O3 composite material of the present application only decreases by 6.73% under the same conditions, which shows significant stability and high efficiency.

[0006] In order to achieve the above-mentioned purpose, the specific schemes of the present application are as follows:

[0007] A method for preparing a nano material by using manganese slag, which is prepared in an open air environment, comprising the following steps:

[0008] Step 1, drying, crushing, ball milling and sieving the manganese slag to obtain manganese slag powder A;

[0009] Step 2, dissolving the manganese slag powder A in a sulfuric acid solution with a concentration of 15-25%, heating and stirring, and reacting, then cooling to room temperature in an air atmosphere, and then centrifugal filtration separation to obtain a filtrate, adding a sulfuric acid solution with a concentration of 15-25% to the filtrate to adjust the pH to ≤2, and then filtering through a filter membrane to obtain an iron and manganese-containing filtrate B;

[0010] Step 3, taking the iron and manganese-containing filtrate B and placing it in a beaker, and adjusting the pH of the iron and manganese-containing filtrate B to 5.9-6.1 with a NaOH solution, continuing to stir and then centrifugal filtration to obtain a ferric hydroxide filter residue, rinsing with deionized water and drying to obtain solid ferric hydroxide particles;

[0011] Step 4, taking the solid ferric hydroxide particles, adding them to a hydrochloric acid solution with a concentration of 8-12% to obtain a ferric chloride solution, and then adding nickel chloride hexahydrate to obtain a nickel-iron mixed solution C;

[0012] Step 5, grinding the green tea, adding it to distilled water, heating in a water bath, and then filtering the solution to obtain a green tea extract D after cooling to room temperature;

[0013] Step 6, using liquid reduction method, slowly drop green tea extract D into nickel-iron mixed solution C under open air environment, get iron-nickel mixed suspension E, after suction filtration, get nano zero-valent iron-nickel particles, wash the nano zero-valent iron-nickel particles with deionized water, then wash with anhydrous ethanol, then dry and grind the nano zero-valent iron-nickel particles to get nZVN-I@Fe2O3 coated with Fe2O3 shell, the nZVN-I@Fe2O3 coated with Fe2O3 shell has a particle size of 100-300 nm.

[0014] Further, the manganese slag in step 1 is a solid waste manganese slag produced by wet smelting, and the drying temperature is 100-110℃.

[0015] Further, in step 2, the solid-liquid ratio of manganese slag powder A to sulfuric acid solution with a concentration of 15-25% is 1:10, the heating and stirring temperature is 30-40℃, and the reaction time is 50-70min.

[0016] Further, in step 3, the deionized water is washed for 3 times, the drying temperature is 55-65℃, and the drying time is 12h.

[0017] Further, in step 4, the solid-liquid ratio of the iron hydroxide particles to hydrochloric acid with a concentration of 8-10% is 0.2675g:250mL, and the iron-nickel molar ratio of the ferric chloride solution to nickel chloride hexahydrate is 1:0.1-0.5.

[0018] Further, in step 5, the water bath temperature is 70-90℃, and the heating time is 1h.

[0019] Further, in step 6, the volume ratio of green tea extract D to nickel-iron mixed solution C is 1:5, the standing time is 30min, the drying temperature is 55-65℃, the drying time is 12h, and the washing with deionized water is 3 times and the washing with anhydrous ethanol is 3 times.

[0020] A nZVN-I@Fe2O3 coated with Fe2O3 shell prepared by the method.

[0021] A nZVN-I@Fe2O3 coated with Fe2O3 shell prepared by the method for use in activating persulfate to degrade antibiotics in water, the antibiotics including but not limited to norfloxacin.

[0022] Further, the method comprises the following steps:

[0023] Step S1, the prepared nZVN-I@Fe2O3 and persulfate are added to the norfloxacin solution to obtain a mixed solution F, and the mass ratio of nZVN-I@Fe2O3, persulfate and norfloxacin is 1g:2.4~4.3g:50~100mg;

[0024] Step S2, after adjusting the pH value of the mixed solution F in step S1 to 3~9, the mixed solution F is placed in a constant temperature oscillator for oscillation reaction, the temperature is set to 30℃, and the oscillation speed is 180r / min, and samples are taken at 5min, 10min, 20min, 30min, 60min, 90min, 120min, 150min and 180min after the reaction starts respectively, and the norfloxacin concentration is determined.

[0025] Advantages of the present application

[0026] 1, the method for preparing nanomaterials from manganese slag in the present application uses the solid waste manganese slag produced in the manganese ore wet smelting process, which has an iron content of 7~10%, extracts the iron in the manganese slag and utilizes it as a resource, which conforms to the development concept of comprehensive utilization of solid waste, and provides a new idea for the treatment and disposal of solid waste.

[0027] 2, the present application uses manganese slag for resource utilization, and the preparation process does not require a nitrogen atmosphere, but is carried out in an aerobic environment under an air atmosphere, and uses environmentally friendly green tea extract as a reducing agent, compared with the traditional method of reducing zero-valent iron by sodium borohydride, the method of the present application is relatively environmentally friendly, the preparation process is relatively simple to manage, and the organic components in the green tea extract can also play the role of dispersing agent and masking agent in the synthesis process of the material, thereby alleviating the agglomeration phenomenon of nano zero-valent iron and improving the dispersibility and stability of the material.

[0028] 3, the preparation method of the present application is carried out in an aerobic environment under an air atmosphere, and a nano iron-nickel bimetallic composite material with a Fe2O3 shell on the surface is prepared. On the one hand, the Fe2O3 shell can effectively protect the Fe 0 and Ni 0 core inside, prevent them from being rapidly oxidized in the air during use and storage, thereby significantly improving the stability and storage time of the material, effectively delaying the oxidation process of the internal iron core, and at the same time, the Fe2O3 shell can accelerate the transfer of electrons from the Fe 0 core to the Fe2O3 shell; on the other hand, the material is composed of iron and nickel, and nickel is a transition non-precious metal, which has not been filled in the 3d orbital, and can form a primary cell with Fe 0 in nZVI to accelerate electron transfer and reduce reaction activation energy during the degradation of pollutants, which is an ideal modified material of zero-valent iron. The nano zero-valent iron modified by nickel can alleviate the agglomeration phenomenon of nano zero-valent iron, and also promote the activation of PS and the degradation of antibiotics.

[0029] 4. The application of the nano zero-valent iron nickel composite material, through nZVN-I@Fe2O3 activated PS in the production of SO4 - ˙and OH - ˙free radicals, adjust the pH value of the reaction solution, the reaction temperature, the PS dosage, the degradation rate of NOR in water is up to 99.82%. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The electron microscope characterization diagram of nZVN-I@Fe2O3 prepared in example 3 of the application, wherein a and b are scanning electron microscope images, c and d are transmission electron microscope images.

[0031] Figure 2 The X-ray photoelectron spectrogram and X-ray diffraction diagram of nZVN-I@Fe2O3 prepared in example 3 of the application; wherein, Figure I and Ⅱ are O1s and Fe 2p spectra of material X-ray photoelectron spectroscopy characterization respectively, Figure III is the X-ray diffraction diagram of material nZVN-I@Fe2O3 activated PS before and after degradation of NOR (a) and (b).

[0032] Figure 3 The degradation efficiency diagram of nZVN-I@Fe2O3 prepared in example 3 of the application to NOR when activated by different PS concentrations.

[0033] Figure 4 The degradation efficiency diagram of nZVN-I@Fe2O3 prepared in example 3 of the application to NOR when activated by PS under different pH conditions.

[0034] Figure 5 The degradation efficiency diagram of nZVN-I@Fe2O3 prepared in example 3 of the application to NOR when activated by PS and other comparative materials.

[0035] Figure 6 The degradation efficiency diagram of nZVN-I@Fe2O3 prepared in example 3 of the application to NOR when activated by PS after 45 days of storage in air. DETAILED DESCRIPTION

[0036] The application will be further explained and described below in conjunction with the drawings and specific embodiments, and it should be noted that the specific embodiments are not used to limit the scope of the application.

[0037] Example 1

[0038] The method for extracting nano material solid iron hydroxide particles from manganese slag is as follows:

[0039] Step 1, the solid waste manganese slag produced by hydrometallurgy was dried in a blast drying oven at 105℃, crushed, ball milled, and sieved through a 200 mesh sieve to obtain manganese slag powder A;

[0040] Step 2, 100g of manganese slag powder A was added to a 20% sulfuric acid solution at a solid-liquid ratio of 1:10, and placed in a constant temperature water bath stirrer to heat and stir at a temperature of 35℃. After 60 minutes of reaction, the heating was stopped, and the mixture was cooled to room temperature in an air atmosphere, then centrifuged, and then a 20% sulfuric acid solution was added to the filtrate to adjust the pH to 2, then left to stand for 24 hours, and then filtered through a 0.45µm filter membrane to remove colloidal substances such as calcium sulfate from the solution, obtaining a filtrate B containing iron and manganese;

[0041] Step 3, the filtrate B containing iron and manganese obtained in step 2 was placed in a beaker, a rotor was added, and placed on a magnetic stirrer. Under rapid stirring, a 12.5mol / L NaOH solution was used to adjust the pH of the filtrate B containing iron and manganese to 6. This is based on the fact that iron ions have a high charge and a small ionic radius, and have a strong affinity for OH - , with a hydrolysis constant Ka≈4.0×10 -3 , which is close to the level of a medium-strong acid. Therefore, iron ions can begin to hydrolyze to form iron hydroxide precipitate when the pH is greater than 2.87, and the iron ions can be completely precipitated when the pH reaches 6. Depending on the concentration, manganese ions generally begin to precipitate when the pH is greater than 8. Therefore, by adjusting the pH to around 6, iron ions can be fully formed into iron hydroxide particles, while ensuring the separation of manganese ions from iron ions. Continue stirring for 30 minutes to allow the iron ions to fully react. After the reaction is complete, let it stand for 30 minutes, then centrifuge and filter to obtain iron hydroxide filter residue. Rinse the filter residue with deionized water three times, and then place it in a blast drying oven at a temperature of 60℃ for 12 hours to obtain solid iron hydroxide particles. The total efficiency of iron extraction from manganese slag in this example is 99.16%.

[0042] The chemical composition of the manganese slag used in Example 1 is shown in Table 1:

[0043] Table 1 Chemical composition of electrolytic manganese slag (mass fraction / %)

[0044]

[0045] The experimental results of sulfuric acid leaching and hydrolysis precipitation in Example 1 are shown in Table 2:

[0046] Table 2 Experimental results of iron extraction by acid leaching followed by hydrolysis precipitation

[0047]

[0048] Example 2

[0049] The method for preparing nanomaterials by using manganese slag comprises the following steps:

[0050] Step 1, 0.2675 g of solid iron hydroxide particles obtained in Example 1 is added into 250 mL of hydrochloric acid with a concentration of 10% to completely dissolve the iron hydroxide particles to obtain an iron chloride solution, and then nickel chloride hexahydrate is added according to a molar ratio of iron to nickel of 1:0.1 to obtain a nickel-iron mixed solution C.

[0051] Step 2, after the green tea is ground, 12 g of the green tea is added into 200 mL of distilled water, and heated in a water bath at a temperature of 80 ℃ for 1 h; after the solution is cooled to room temperature, filtration is performed to obtain a green tea extract D;

[0052] Step 3, in an open air environment, 40 mL of the green tea extract D is slowly dropped into 200 mL of the solution C within 10 min by using a liquid phase reduction method; after standing for 30 min, an iron-nickel mixed suspension E is obtained; the purpose of standing for 30 min is to make the reducing substances such as tea polyphenols in the green tea extract fully react with the iron ions and the nickel ions in the solution C, so as to reduce the iron ions and the nickel ions into zero-valent iron and zero-valent nickel; after suction filtration, nanometer zero-valent iron-nickel particles are obtained; the obtained nanometer zero-valent iron-nickel particles are washed with deionized water for 3 times and then washed with anhydrous ethanol for 3 times; the deionized water and the anhydrous ethanol are used for multiple times of washing, so as to remove other impurities on the surface of the zero-valent iron-nickel particles; then the nanometer zero-valent iron-nickel particles are placed into a drying box and dried at a temperature of 60 ℃ for 12 h, and then ground to obtain nZVN-I@Fe2O3; the reduction reaction is performed by using the sampling liquid phase reduction method in an open air environment, and the drying is performed in a non-nitrogen reduction atmosphere, so as to form a Fe2O3 shell on the surface of the nanometer zero-valent iron-nickel particles.

[0053] Example 3

[0054] The method for preparing nanomaterials by using manganese slag comprises the following steps:

[0055] Step 1, 0.2675 g of solid iron hydroxide particles obtained in Example 1 is added into 250 mL of hydrochloric acid with a concentration of 10% to completely dissolve the iron hydroxide particles to obtain an iron chloride solution, and then nickel chloride hexahydrate is added according to a molar ratio of iron to nickel of 1:0.3 to obtain a nickel-iron mixed solution C.

[0056] Step 2, after the green tea is ground, 12 g of the green tea is added into 200 mL of distilled water, and heated in a water bath at a temperature of 80 ℃ for 1 h; after the solution is cooled to room temperature, filtration is performed to obtain a green tea extract D;

[0057] Step 3, using liquid phase reduction method, 40 mL green tea extract D was slowly dropped into 200 mL solution C in 10 min under open air environment, and iron-nickel mixed suspension E was obtained after standing for 30 min, and then nZVN-I@Fe2O3 was obtained by filtering, washing the obtained nZVN-I@Fe2O3 with deionized water for 3 times, and then with anhydrous ethanol for 3 times, and then drying the nZVN-I@Fe2O3 in a drying oven at 60℃ for 12 h, and then grinding to obtain nZVN-I@Fe2O3.

[0058] Figure 1 The scanning electron microscope picture of nZVN-I@Fe2O3 under 100000 times magnification is shown, from which it can be seen that the particle size of nZVN-I@Fe2O3 is about 200 nm, which is a nanomaterial. Under 100000 times magnification, the nanomaterial appearing in the same lens is a single particle, indicating that the material has good dispersibility and no obvious agglomeration phenomenon, which is because the organic components in the green tea extract play the role of dispersant and masking agent in the synthesis of the material. It can also be seen that the nanomaterial has a clear spherical structure and a clear light and dark boundary, which is a typical core-shell structure material. The material is measured using a ruler, and the material shell thickness is between 12-21 nm. Figure 1

[0059] Figure 2 The X-ray photoelectron spectrum and X-ray diffraction pattern of nZVN-I@Fe2O3 are shown in the following (I) and (II).

[0060] Figure 2 (I) is the O1s peak chart of the X-ray photoelectron spectrum of nZVN-I@Fe2O3. After peak fitting of the original peak, three peaks are obtained, which are 533.41 eV, 532.53 eV and 531.47 eV, respectively, corresponding to C-O functional group, metal state -OH and -O2 functional group, respectively, indicating that there is an oxide on the surface of the material. -

[0061] Figure 2 (II) is the X-ray photoelectron spectrum of nZVN-I@Fe2O3: Fe2p chart. After peak fitting of the original peak, five peaks are obtained, which are 724.79 eV, 717.45 eV, 713.87 eV, 711.47 eV and 706.07 eV. Among them, the peak at 724.79 eV represents Fe2p1 / 2, and the peak at 713.87 eV also represents Fe2p3 / 2, which are the characteristic peaks of Fe2p, indicating that the material contains Fe2O3. 3+ ​​The satellite peak at 717.45 eV indicates the presence of Fe2O3 on the material surface; the peak at 717.45 eV corresponds to a hybrid peak, indicating that the introduction of Ni induces a multivalent distribution of Fe during the material synthesis process, forming some iron oxide or iron hydroxyl species on the material surface, such as Fe2O3 and FeOOH. This environment helps to improve electron migration efficiency and the diversity of active sites; the peak at 711.47 eV corresponds to Fe2p3 / 2; and the peak at 706.07 eV corresponds to Fe2p3 / 2. 0 .

[0062] Figure 2 (III) are the X-ray diffraction patterns of nZVN-I@Fe2O3 activated PS before (curve a) and after (curve b) degradation of NOR. In curve a, organic matter, Fe2O3, and Fe appear. 0 and Ni 0 The diffraction absorption peaks did not show any peaks representing manganese, indicating the presence of organic matter on the material surface. Fe₂O₃ is formed by the oxidation of zero-valent iron in air, and no other iron oxide-related diffraction peaks were observed in the spectrum. However, in curve b after the degradation reaction, peaks representing Ni are clearly visible. 0 and Fe 0 The peaks all disappeared during the reaction, indicating that Ni 0 and Fe 0 All participated in the reaction. Furthermore, the peak intensity representing Fe2O3 was significantly enhanced, and the combination... Figure 2 (II) The presence of impurity peaks in the X-ray photoelectron spectrum further indicates that Ni doping promotes Fe... 2+ To Fe 3+ The transformation and promotion of Fe2O3 crystal phase can alleviate the agglomeration of zero-valent iron to some extent.

[0063] Figure 1 and Figure 2 Characterization results show that the preparation method of the present invention can successfully prepare nanoscale nZVN-I@Fe2O3 composite materials with core-shell structure.

[0064] Example 4

[0065] The method for preparing nanomaterials using manganese slag includes the following steps:

[0066] Step 1: Weigh 0.2675 g of solid ferric hydroxide particles obtained in Example 1, add them to 250 mL of 10% hydrochloric acid to completely dissolve the ferric hydroxide particles to obtain ferric chloride solution, and then add nickel chloride hexahydrate at a molar ratio of 1:0.5 to obtain nickel-iron mixture C.

[0067] Step 2, after grinding the green tea, 12 g was weighed and added to 200 mL of distilled water, and heated in a water bath at 80℃ for 1 h. After the solution cooled to room temperature, filtration was performed to obtain green tea extract D;

[0068] Step 3, using the liquid reduction method, 40 mL of green tea extract D was slowly dropped into 200 mL of solution C in an open air environment within 10 min. After standing for 30 min, iron-nickel mixed suspension E was obtained. After suction filtration, nano zero-valent iron-nickel particles were obtained. The obtained nano zero-valent iron-nickel particles were washed with deionized water for 3 times, and then washed with anhydrous ethanol for 3 times. Then the nano zero-valent iron-nickel particles were placed in a drying oven and dried at 60℃ for 12 h, and then ground to obtain nZVN-I@Fe2O3.

[0069] Example 5

[0070] The application of nZVN-I@Fe2O3 prepared in Examples 2, 3 and 4 to degrade NOR is as follows:

[0071] 0.01 g of nZVN-I@Fe2O3 in Examples 2 to 4 and 0.033 g of PS were added to 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution. The pH of the mixed solution was adjusted to 3 and placed in a constant temperature oscillator. The oscillation speed was set to 180 r / min and the temperature was set to 30℃. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the reaction started, and the concentration of NOR was measured. After 180 min of reaction, the degradation efficiency of NOR by the materials in each example was as follows:

[0072] The degradation efficiency of NOR by nZVN-I@Fe2O3 prepared in Example 2 activated PS was 78.80%.

[0073] The degradation efficiency of NOR by nZVN-I@Fe2O3 prepared in Example 3 activated PS was 99.66%.

[0074] The degradation efficiency of NOR by nZVN-I@Fe2O3 prepared in Example 4 activated PS was 80.18%.

[0075] Example 6

[0076] The application of nZVN-I@Fe2O3 prepared in Example 3 to degrade NOR is as follows:

[0077] 0.01 g of nZVN-I@Fe2O3 and 0.024 g of PS were added to 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution, the pH of the mixed solution was adjusted to 3, and then the mixed solution was placed in a constant temperature oscillator, the oscillation speed was set to 180 r / min, and the temperature was set to 30°C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the reaction started, and the NOR concentration was determined. After 180 min of reaction, the nZVN-I@Fe2O3 prepared in Example 3 had a degradation efficiency of 86.38% for NOR.

[0078] Example 7

[0079] The application method of nZVN-I@Fe2O3 prepared in Example 3 for degrading NOR is as follows:

[0080] 0.01 g of nZVN-I@Fe2O3 and 0.029 g of PS were added to 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution, the pH of the mixed solution was adjusted to 3, and then the mixed solution was placed in a constant temperature oscillator, the oscillation speed was set to 180 r / min, and the temperature was set to 30°C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the reaction started, and the NOR concentration was determined. After 180 min of reaction, the nZVN-I@Fe2O3 prepared in Example 3 had a degradation efficiency of 86.38% for NOR.

[0081] Example 8

[0082] The application method of nZVN-I@Fe2O3 prepared in Example 3 for degrading NOR is as follows:

[0083] 0.01 g of nZVN-I@Fe2O3 and 0.033 g of PS were added to 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution, the pH of the mixed solution was adjusted to 3, and then the mixed solution was placed in a constant temperature oscillator, the oscillation speed was set to 180 r / min, and the temperature was set to 30°C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the reaction started, and the NOR concentration was determined. After 180 min of reaction, the nZVN-I@Fe2O3 prepared in Example 3 had a degradation efficiency of 86.38% for NOR.

[0084] Example 9

[0085] The application of nZVN-I@Fe2O3 prepared in Example 3 in degrading NOR is as follows:

[0086] 0.01 g of nZVN-I@Fe2O3 and 0.038 g of PS were added to 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution, and the pH of the mixed solution was adjusted to 3 and then placed in a constant temperature oscillator, with the oscillation speed set to 180 r / min and the temperature set to 30°C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the start of the reaction, and the NOR concentration was determined. After 180 min of reaction, the degradation efficiency of nZVN-I@Fe2O3 of Example 3 on NOR reached 83.45%.

[0087] Example 10

[0088] The application of nZVN-I@Fe2O3 prepared in Example 3 in degrading NOR is as follows:

[0089] 0.01 g of nZVN-I@Fe2O3 and 0.043 g of PS were added to 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution, and the pH of the mixed solution was adjusted to 3 and then placed in a constant temperature oscillator, with the oscillation speed set to 180 r / min and the temperature set to 30°C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the start of the reaction, and the NOR concentration was determined. After 180 min of reaction, the degradation efficiency of nZVN-I@Fe2O3 of Example 3 on NOR reached 80.52%.

[0090] The degradation of NOR by nZVN-I@Fe2O3 in the activation of different concentrations of PS is shown in Table 1. Figure 3 As can be seen from Table 1, for 100 mL of NOR solution with a concentration of 5 mg / L, when the PS dosage is ≤0.033 g, the degradation rate of NOR by nZVN-I@Fe2O3 activated PS increases with the increase of PS dosage; otherwise, when the PS dosage is >0.033 g, the degradation rate decreases with the increase of PS dosage.

[0091] Example 11

[0092] The application of nZVN-I@Fe2O3 prepared in Example 3 in degrading NOR is as follows:

[0093] 0.01 g of nZVN-I@Fe2O3 and 0.033 g of PS were added to 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution, and the pH of the mixed solution was adjusted to 5 and then placed in a constant temperature oscillator, with the oscillation speed set to 180 r / min and the temperature set to 30°C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min, and 180 min after the reaction started, and the NOR concentration was determined. After 180 min of reaction, the nZVN-I@Fe2O3 of Example 3 had a degradation efficiency for NOR of 99.82%. It can be seen that the nZVN-I@Fe2O3 has the highest degradation efficiency for NOR at pH = 5, because at this pH value, the Fe2O3 shell can more effectively release Fe 2+ ions, thereby efficiently activating PS to generate free radicals and promoting the degradation of NOR.

[0094] Example 12

[0095] The application of nZVN-I@Fe2O3 prepared in Example 3 to degrade NOR is as follows:

[0096] 0.01 g of nZVN-I@Fe2O3 and 0.033 g of PS were added to 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution, and the pH of the mixed solution was adjusted to 7 and then placed in a constant temperature oscillator, with the oscillation speed set to 180 r / min and the temperature set to 30°C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min, and 180 min after the reaction started, and the NOR concentration was determined. After 180 min of reaction, the nZVN-I@Fe2O3 of Example 3 had a degradation efficiency for NOR of 77.94%.

[0097] Example 13

[0098] The application of nZVN-I@Fe2O3 prepared in Example 3 to degrade NOR is as follows:

[0099] 0.01 g of nZVN-I@Fe2O3 and 0.033 g of PS were added into 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution, and the pH of the mixed solution was adjusted to 9. The mixed solution was placed in a constant temperature oscillator, the oscillation speed was set to 180 r / min, and the temperature was set to 30°C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the reaction started, and the NOR concentration was determined. After 180 min of reaction, the degradation efficiency of nZVN-I@Fe2O3 of Example 3 on NOR reached 71.38%.

[0100] Examples 8, 11 to 13 are the experimental results of nZVN-I@Fe2O3 activating PS to degrade NOR at different pH values, as shown in Figure 4 It can be seen that for 100 mL of NOR solution with a concentration of 5 mg / L, the degradation efficiency of the material of Example 3 on NOR increases first and then decreases with the increase of pH, and when pH = 5, the efficiency of nZVN-I@Fe2O3 activating PS to degrade NOR is the highest. The pH of the Fenton technology for treating wastewater is generally below 4, but the nZVN-I@Fe2O3 of Example 3 has a wider pH application range and a higher degradation efficiency than Fe 2+ The Fenton technology of nZVN-I@Fe2O3 activated hydrogen peroxide has a wider pH application range and a higher degradation efficiency. Compared with the traditional Fenton technology oxidation method, nZVN-I@Fe2O3 can expand the pH application range of the material to pH 5 while maintaining a high degradation efficiency of NOR, thereby effectively reducing the cost of adjusting pH in the actual water treatment process, and thus the nZVN-I@Fe2O3 has good controllability and promotion potential in actual operation.

[0101] Example 14

[0102] The nZVN-I@Fe2O3 prepared in Example 3 was compared with the nano zero-valent iron nickel material nZVN-I without a Fe2O3 shell and the zero-valent iron nano material nZVI@Fe2O3 without nickel doping in the application of single degradation or activating PS to degrade NOR under the same conditions as follows:

[0103] 0.01 g of nZVN-I@Fe2O3, nZVN-I and nZVI@Fe2O3 obtained in Example 3 and 0-0.033 g of PS were added into 100 mL of NOR solution with a concentration of 5 mg / L to obtain a mixed solution, and the mixed solution was placed in a constant temperature oscillator after the pH was adjusted to 5, the oscillation speed was set to 180 r / min, and the temperature was set to 30°C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the reaction started, and the NOR concentration was determined. After 180 min of reaction, the degradation efficiency of nZVN-I@Fe2O3 / PS, nZVN-I / PS, nZVI@Fe2O3 / PS and nZVN-I@Fe2O3 of Example 3 on NOR was 99.82%, 73.80%, 64.48% and 28.10%, respectively.

[0104] Figure 5 The results of experiments in which the above three materials were used alone to degrade NOR or activate PS to degrade NOR under the same conditions are shown in Table 3. Figure 5 It can be seen that the doping of nickel can significantly improve the effect of activating PS by nano zero-valent iron, and the material with a Fe2O3 shell has a better effect on degrading NOR than the material without a Fe2O3 shell, and the combination of PS and nano materials has a better effect on degrading NOR than the degradation of NOR without the participation of PS. This can be attributed to the fact that the bimetallic Ni and Fe can effectively activate PS, and the Fe2O3 shell effectively protects the internal structure while continuously releasing Fe 2+ activating PS to generate SO4 - ˙ and OH - ˙. The reaction formula involved in the process of activating PS by nano zero-valent iron nickel composite material to generate strong oxidizing free radicals is as follows:

[0105]

[0106] Example 15

[0107] The application of nZVN-I@Fe2O3 prepared in Example 3 in degrading NOR is as follows:

[0108] After 0.01 g of nZVN-I@Fe2O3 was stored in air for 45 d, 0.01 g of nZVN-I@Fe2O3 stored for 0 d and 45 d respectively was added to 100 mL of NOR solution with a concentration of 5 mg / L together with 0.033 g of PS to obtain a mixed solution, and the pH of the mixed solution was adjusted to 5 and placed in a constant temperature oscillator, with a shaking speed of 180 r / min and a temperature of 30 °C. Samples were taken at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the reaction started and the concentration of NOR was determined, and the results are shown in Table 3. Figure 6 As can be seen, after 180 min of reaction, the degradation efficiency of nZVN-I@Fe2O3 stored for 45 d to NOR was only 6.73% lower than that of the material on the 0th day, and nZVN-I@Fe2O3 stored for 45 d still had a degradation efficiency of 93.10% to NOR. The degradation efficiency of nZVN-I without a Fe2O3 shell to NOR decreased by 44.06% after being stored for 45 d, as shown in Table 4. Figure 6 This shows that the Fe2O3 shell of nZVN-I@Fe2O3 can delay oxidation, and nZVN-I@Fe2O3 with a Fe2O3 shell structure can still maintain a high efficiency of activating PS to degrade NOR even if it is exposed to air for a long time.

Claims

1. A method for preparing nanomaterials using manganese slag, characterized in that, Preparation is carried out under open air environment conditions, comprising the following steps: Step 1, manganese slag is dried, crushed, ball milled and sieved to obtain manganese slag powder A; the manganese slag is a solid waste manganese slag produced by wet smelting, the drying temperature is 100-110℃, and the manganese slag powder A is sieved through a 200-mesh sieve; Step 2, the manganese slag powder A is dissolved in a 15-25% sulfuric acid solution, heated and stirred, and reacted, and after the reaction, the solution is cooled to room temperature in an air atmosphere, centrifuged and filtered to separate the filtrate, the pH of the filtrate is adjusted to ≤2 by adding a 15-25% sulfuric acid solution, and the solution is filtered to obtain an iron-manganese-containing filtrate B; Step 3, the iron-manganese-containing filtrate B is placed in a beaker, the pH of the iron-manganese-containing filtrate B is adjusted to 5.9-6.1 by adding a NaOH solution, the solution is continuously stirred and centrifuged to obtain a ferric hydroxide filter residue, the residue is washed with deionized water and dried to obtain solid ferric hydroxide particles; Step 4, the solid ferric hydroxide particles are added to an 8-12% hydrochloric acid solution to obtain a ferric chloride solution, and then nickel chloride hexahydrate is added to obtain a nickel-iron mixed solution C; Step 5, green tea is ground and added to distilled water, heated in a water bath, and then filtered to obtain a green tea extract D after the solution is cooled to room temperature; Step 6, the green tea extract D is slowly dropped into the nickel-iron mixed solution C under open air environment conditions by using a liquid phase reduction method to obtain an iron-nickel mixed suspension E, and then nanometer zero-valent iron-nickel particles are obtained by suction filtration, washed with deionized water, washed with anhydrous ethanol, and then dried and ground to obtain nZVN-I@Fe2O3 with a Fe2O3 shell on the surface, wherein the nZVN-I@Fe2O3 with a Fe2O3 shell on the surface has a particle size of 100-300nm.

2. The method of claim 1, wherein, In step 2, the solid-liquid ratio of the manganese slag powder A to the 15-25% sulfuric acid solution is 1:10, the heating and stirring temperature is 30-40℃, and the reaction time is 50-70min.

3. The method of claim 1, wherein, In step 3, the continuous stirring time is 25-35min, the deionized water is washed for 3 times, the drying temperature is 55-65℃, and the drying time is 12h.

4. The method of claim 1, wherein, In step 4, the solid-liquid ratio of the ferric hydroxide particles to the 8-10% hydrochloric acid is 0.2675g:250mL, and the iron-nickel molar ratio of the ferric chloride solution to the nickel chloride hexahydrate is 1:0.1-0.

5.

5. The method of claim 1, wherein, In step 5, the water bath temperature is 70-90℃, and the heating time is 1h.

6. The method of claim 1, wherein, In step 6, the volume ratio of the green tea extract D to the nickel-iron mixed solution C is 1:5, the standing time is 30min, the drying temperature is 55-65℃, the drying time is 12h, the deionized water is washed for 3 times, and the anhydrous ethanol is washed for 3 times.

7. nZVN-I@Fe2O3 with a Fe2O3 shell on the surface prepared by using the method of any one of claims 1-6.

8. The use of nZVN-I@Fe2O3 prepared by the method of any one of claims 1-6, which is coated with an Fe2O3 shell, in the activated persulfate degradation of antibiotics in water, including but not limited to norfloxacin.

9. Use according to claim 8, characterized in that, The method comprises the following steps: Step S1: adding the prepared nZVN-I@Fe2O3 and persulfate to a norfloxacin solution to obtain a mixed solution F, wherein the mass ratio of nZVN-I@Fe2O3, persulfate and norfloxacin is 1 g: 2.4-4.3 g: 50-100 mg; Step S2: adjusting the pH of the mixed solution F of step S1 to 3-9, and then placing it in a constant temperature oscillator for oscillation reaction, with a temperature setting of 30°C and an oscillation speed of 180 r / min; sampling at 5 min, 10 min, 20 min, 30 min, 60 min, 90 min, 120 min, 150 min and 180 min after the start of the reaction, respectively, and determining the norfloxacin concentration.

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