An aop catalyst of fe-ni embedded in two-dimensional nitrogen-doped carbon, a preparation method and applications thereof

Abstract

The application discloses an AOP catalyst of FeNi embedded two-dimensional nitrogen-doped carbon, a preparation method and application thereof, and relates to the following steps: adding iron salt and nickel salt into a solvent to prepare solution A; adding terephthalic acid into the solvent to prepare solution B; mixing the solution A and the solution B to prepare solution C; performing a solvothermal reaction on the solution C, and washing and drying to obtain FeNi-MOF; adding the FeNi-MOF into a Tris-HCl solution to obtain solution D; adding dopamine hydrochloride into the solution D, performing magnetic stirring for 22-26 hours, and washing and drying to obtain FeNi-MOF@PDA; and carbonizing the FeNi-MOF@PDA under nitrogen protection at 600-900 DEG C for 1-3 hours to obtain the AOP catalyst based on FeNi embedded two-dimensional nitrogen-doped carbon. The catalyst obtained by the method can complete 99% efficient degradation of tetracycline within 40 minutes.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst, preparation method and its application, belong to AOP catalyst technical field. BACKGROUND

[0002] Tetracycline is a commonly used broad-spectrum antibiotic in livestock and aquaculture industry. However, tetracycline is difficult to degrade in the environment and can enter water bodies through feces, sewage, surface runoff and other pathways, persisting in aquatic environments. Tetracycline is toxic to aquatic organisms, affecting their growth, reproduction and even causing death. It can also enter the human body through the food chain, causing endocrine disorders, liver damage, kidney damage and other problems. In addition, the antibiotics remaining in the water can promote the production of antibiotic resistance genes in microorganisms, increasing the risk of human infection with drug-resistant bacteria and reducing the therapeutic effect of antibiotics. Therefore, reducing the content of tetracycline in the water environment has important positive effects.

[0003] The advanced oxidation process based on persulfate (PS-AOPs) is an emerging technology for degrading toxic organic pollutants. It activates peroxodisulfate (PDS) or peroxymonosulfate (PMS) to generate sulfate radicals SO4 ·- with strong oxidizing properties. The degradation pathway dominated by persulfate radicals has a very high oxidation potential (2.50-3.10 eV), a relatively long half-life (30-40 μs) and a wider pH range (2.0-9.0), showing great potential and advantages in treating water-borne refractory organic pollutants, such as tetracycline.

[0004] However, peroxodisulfate (PDS) or peroxymonosulfate (PMS) itself cannot automatically generate sulfate radicals with strong oxidizing properties, and some catalysts, i.e. AOP catalysts, are needed. Studies have shown that some iron-based metal (or metal oxide) supported catalysts can effectively activate persulfate to generate sulfate radicals to degrade organic pollutants. However, as the active center of the catalyst, pure solid Fe(III) / Fe(II) conversion is slow and the catalytic efficiency is low, which is a key factor affecting the efficiency of interface electron transfer and radical generation. Therefore, it is necessary to construct an iron-based catalyst with high catalytic efficiency to achieve rapid transfer of interface charge and continuous catalytic system. SUMMARY

[0005] The present application provides a kind of FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst, preparation method and its application, which can effectively solve the above problems.

[0006] The application is implemented as follows:

[0007] The application discloses a preparation method of an AOP catalyst with FeNi embedded in two-dimensional nitrogen-doped carbon, and has the characteristics that the method comprises the following steps:

[0008] S1, iron salt and nickel salt are added into a solvent to prepare solution A; terephthalic acid is added into a solvent to prepare solution B; solution A and solution B are mixed to prepare solution C; solution C is subjected to a solvothermal reaction, and then washed and dried to obtain FeNi-MOF;

[0009] S2, FeNi-MOF is added into a Tris-HCl solution to obtain solution D; dopamine hydrochloride is added into solution D, and then subjected to magnetic stirring for 22-26 hours; and then the mixture is washed and dried to obtain FeNi-MOF@PDA;

[0010] S3, FeNi-MOF@PDA is carbonized at 600-900 DEG C under nitrogen protection for 1-3 hours to obtain the AOP catalyst based on FeNi embedded in two-dimensional nitrogen-doped carbon.

[0011] As a further improvement, the iron salt is at least one of ferric chloride hexahydrate and ferric nitrate nonahydrate.

[0012] As a further improvement, the nickel salt is at least one of nickel nitrate hexahydrate and nickel chloride hexahydrate.

[0013] As a further improvement, the solvent is N,N-dimethylformamide.

[0014] As a further improvement, the molar ratio of the iron salt, the nickel salt and terephthalic acid is 1-2:1-2:2-4.

[0015] As a further improvement, the mass ratio of FeNi-MOF to dopamine hydrochloride is 8-12:1.

[0016] As a further improvement, the temperature rising rate in step S3 is 2.5-3.5 DEG C / min.

[0017] An AOP catalyst with FeNi embedded in two-dimensional nitrogen-doped carbon prepared by the above method.

[0018] A method for degrading tetracycline by using an AOP catalyst with FeNi embedded in two-dimensional nitrogen-doped carbon, which comprises the following steps: FeNi embedded in two-dimensional nitrogen-doped carbon and persulfate are added into a tetracycline solution to perform a degradation reaction in the dark.

[0019] As a further improvement, the use concentration of the FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst is 0.45-0.55 g / L, and the use concentration of the persulfate is 180-220 mg / L.

[0020] The beneficial effects of the present application are:

[0021] The present application constructs a FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst, which has multiple metal active centers, improves the efficiency of interface electron transfer and free radical generation, realizes rapid transfer of interface charge and continuous catalytic system, has high catalytic efficiency, and overcomes the problem of slow conversion speed of traditional iron-based catalysts which only have simple solid Fe(III) / Fe(II) conversion centers.

[0022] The FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst of the present application has excellent catalytic performance in catalytic degradation of tetracycline under light-proof conditions, and can complete 99% efficient degradation of tetracycline within 40 min. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0024] Figure 1 The SEM electron microscope graph of FeNi@2D NC provided for the present application embodiment 1.

[0025] Figure 2 The XRD graph of FeNi@2D NC provided for the present application embodiment 1.

[0026] Figure 3 The Raman spectrum of FeNi@2D NC provided for the present application embodiment 1.

[0027] Figure 4 The degradation curve graph of FeNi@2D NC provided for the present application embodiment 2 under light-proof conditions catalytic degradation of tetracycline. DETAILED DESCRIPTION

[0028] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0029] The embodiment of the present application provides a preparation method of an AOP catalyst of FeNi embedded two-dimensional nitrogen-doped carbon, characterized in that the method comprises the following steps:

[0030] S1, iron salt and nickel salt are added into a solvent to prepare solution A; terephthalic acid is added into a solvent to prepare solution B; solution A and solution B are mixed to prepare solution C; solution C is subjected to a solvothermal reaction, and then washed and dried to obtain FeNi-MOF; the solvothermal reaction is preferably performed at a temperature of 130-150 DEG C for 44-50 hours, and under the condition, the iron salt and the nickel salt are converted into a bimetallic nanostructured metal organic framework compound of FeNi.

[0031] S2, FeNi-MOF is added into a Tris-HCl solution to obtain solution D; dopamine hydrochloride is added into solution D, and then subjected to magnetic stirring for 22-26 hours, and then washed and dried to obtain FeNi-MOF@PDA; in the reaction, the pH is preferably 8-9, and the dopamine hydrochloride is polymerized into polydopamine under alkaline conditions, and the polydopamine uniformly coats the outer layer of FeNi-MOF.

[0032] S3, FeNi-MOF@PDA is carbonized at 600-900 DEG C for 1-3 hours under nitrogen protection to obtain the AOP catalyst based on FeNi embedded two-dimensional nitrogen-doped carbon. In the high-temperature carbonization process, the metal organic framework compound serves as a carbon source and is graphitized, and the polydopamine coating layer serves as a nitrogen source and is doped in the graphitized carbon to form a composite catalyst FeNi@2D NC with a two-dimensional layered structure of nitrogen-doped carbon network.

[0033] In some embodiments, the iron salt is at least one of ferric chloride hexahydrate and ferric nitrate nonahydrate, but is not limited thereto.

[0034] In some embodiments, the nickel salt is at least one of nickel nitrate hexahydrate, nickel chloride hexahydrate, but is not limited thereto.

[0035] In some embodiments, the solvent is N,N-dimethylformamide.

[0036] In some embodiments, the molar ratio of the iron salt, the nickel salt, and terephthalic acid is 1-2: 1-2: 2-4. This ratio is very critical for the formation of FeNi-MOF, and if it is not within this range, it will be difficult to form the FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst of the present application.

[0037] In some embodiments, the mass ratio of the FeNi-MOF to dopamine hydrochloride is 8-12: 1. This ratio is very critical for the formation of the metal-embedded two-dimensional nitrogen-doped carbon layer structure of the catalyst, and if it is not within this range, it will be difficult to form the FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst of the present application.

[0038] In some embodiments, the temperature rising rate in step S3 is 2.5-3.5℃ / min.

[0039] The FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst prepared by the above method is provided in the embodiments of the present application. In this catalyst, the metal is embedded in the structure of the two-dimensional nitrogen-doped carbon, which also helps to evenly distribute the FeNi metal active centers and reduce the loss of metal caused by direct contact of the metal with the solution, improve the stability of the catalyst, and thus improve the catalytic efficiency of the catalyst. In addition, when degrading organic pollutants with this catalyst, the two-dimensional nitrogen-doped carbon layer in the structure and the FeNi metal active center will form a synergistic effect, together improving the degradation of the free radical pathway and the non-free radical pathway, effectively improving the degradation efficiency.

[0040] The embodiments of the present application provide a method for degrading tetracycline using a FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst, which comprises the following steps: adding the FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst and persulfate to a tetracycline solution and performing a degradation reaction in the dark.

[0041] In some embodiments, the use concentration of the FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst is 0.45-0.55g / L, and the use concentration of the persulfate is 180-220mg / L.

[0042] Embodiment 1

[0043] Take 0.5406 g of iron trichloride hexahydrate (2 mmol), 0.5821 g of nickel nitrate hexahydrate (2 mmol) into 30 mL of N,N-dimethylformamide, stir until completely dissolved, to prepare solution A. Take 0.6645 g of terephthalic acid (4 mmol) into 30 mL of N,N-dimethylformamide, stir until dissolved, to prepare solution B. Mix solution A and solution B, stir uniformly, to obtain solution C. Put solution C into a 100 ml hydrothermal kettle, and after solvothermal reaction at 140℃ for 48 hours, wash with ethanol and distilled water respectively until the supernatant is clear. Put into an electric heating air drying oven at 60℃ for 4 hours, to obtain sample FeNi-MOF.

[0044] Take 1.0 g of FeNi-MOF into 100 ml of tris-hydroxymethyl aminomethane hydrochloride (Tris-HCl) solution with pH of 8.5, ultrasonic for 30 min to make it uniformly dispersed, to obtain solution D. Take 0.10 g of dopamine hydrochloride into solution D, stir uniformly. Stir the above solution at room temperature for 24 hours, wash with distilled water until the washing liquid is colorless, put into an oven at 60℃ for 4 hours, to obtain FeNi-MOF@PDA.

[0045] Take 1.0 g of FeNi-MOF@PDA into a high-temperature tube furnace, and heat to 800℃ at a heating rate of 3℃ / min under nitrogen protection, calcine for 2 hours, to finally obtain FeNi@2D NC.

[0046] The SEM image of FeNi@2D NC is shown in Figure 1 As can be seen from Figure 1 A, the FeNi@2D NC composite material is composed of a large number of nanoparticles and a large amount of translucent layered material. The fine structure of the FeNi@2D NC composite material is shown in Figure 1 B, it can be seen that these nanoparticles are close to spherical shape, and the particle size is uniform, about 30-50 nm. These spherical nanoparticles are bimetallic nanostructures of FeNi converted from metal ions / clusters in metal organic framework at high temperature. In addition, further observation of the space structure can see that these nanoparticles are wrapped and separated from each other by a large amount of translucent layered material. The framework of metal organic framework is a good carbon source, and dopamine polymerizes to form polydopamine under alkaline conditions, which is a good nitrogen source, and they are uniformly distributed in the precursor of the composite, so that during the carbonization process at high temperature, nitrogen-doped carbon with two-dimensional layered structure is formed. Therefore, through one-step carbonization of the precursor, a structure of bimetallic FeNi nanoparticles loaded in the two-dimensional nitrogen-doped carbon is formed.

[0047] The XRD pattern of the FeNi@2D NC sample is shown in Figure 2 As can be seen from Figure 2It can be seen that the composite material has three obvious diffraction peaks at 43.5°, 50.7°, and 74.6°, which correspond to the diffraction peaks of metallic FeNi, indicating the presence of FeNi alloy. Furthermore, the sample has two relatively weak and broadened diffraction peaks around 26° (002) and 44° (100), proving the presence of graphitic carbon. The broadened diffraction peak at 26° is mainly caused by defects formed by nitrogen doping in the graphene. These results indicate the presence of nitrogen-doped carbon in the prepared sample.

[0048] The Raman spectrum of FeNi@2D NC is as follows Figure 3 As shown. By Figure 3 It can be seen that the Raman spectra of the samples are all at 1359 cm⁻¹. -1 and 1585cm -1 Two typical peaks appeared on the left and right, belonging to the D-band and G-band respectively. Based on the relative intensity of the D-band and G-band, ID / IG = 0.98, which is less than 1, indicating that the NC material has a high degree of graphitization.

[0049] Example 2

[0050] Experiments on the degradation of tetracycline

[0051] Experimental group: All degradation reactions were carried out in the dark, with an initial tetracycline concentration of 100 mg / L in the reaction solution. 50 mg of catalyst FeNi@2D NC and 0.02 g of KHSO5 (PMS, 200 mg / L) were added to 100 mL of tetracycline (TC) solution. At degradation times of 0, 1, 2, 3, 5, 7, 10, 15, 20, 30, 40, and 60 min, 0.5 mL of the reaction solution was drawn using a syringe, residual oxides were quenched with sodium thiosulfate solution, and the solution was filtered through a 0.22 μm filter. The tetracycline concentration was determined using high-performance liquid chromatography (HPLC) with a C18 column.

[0052] Control group 1: No PMS added, otherwise the same as the experimental group.

[0053] Control group 2: No catalyst FeNi@2D NC was added, otherwise the same as the experimental group.

[0054] The degradation curve of tetracycline catalyzed by FeNi@2D NC under light-protected conditions is shown in the figure below. Figure 4 As shown. By Figure 4 It can be seen that under the action of FeNi@2D NC, tetracycline can be degraded by 99% efficiently within 40 minutes, indicating that it has excellent catalytic performance.

[0055] The above merely describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for degrading tetracycline by FeNi embedded two-dimensional nitrogen-doped carbon AOP catalyst, characterized in that, The method comprises the following steps: The AOP catalyst of FeNi embedded two-dimensional nitrogen-doped carbon and persulfate are added to a tetracycline solution to perform a degradation reaction in the dark, wherein the use concentration of the AOP catalyst of FeNi embedded two-dimensional nitrogen-doped carbon is 0.45-0.55 g / L, and the use concentration of the persulfate is 180-220 mg / L. The preparation method of the AOP catalyst of FeNi embedded two-dimensional nitrogen-doped carbon comprises the following steps: S1, iron salt and nickel salt are added to a solvent to prepare solution A; terephthalic acid is added to a solvent to prepare solution B; solution A and solution B are mixed to prepare solution C; solution C is subjected to a solvothermal reaction, and then washed and dried to obtain FeNi-MOF; S2, FeNi-MOF is added to a Tris-HCl solution to obtain solution D; dopamine hydrochloride is added to solution D, and then subjected to magnetic stirring for 22-26 h, and then washed and dried to obtain FeNi-MOF@PDA; S3, FeNi-MOF@PDA is carbonized at 600-900 DEG C for 1-3 h under nitrogen protection to obtain the AOP catalyst of FeNi embedded two-dimensional nitrogen-doped carbon.

2. The method of claim 1, wherein, The iron salt is at least one of ferric chloride hexahydrate and ferric nitrate nonahydrate.

3. The method of claim 1, wherein, The nickel salt is at least one of nickel nitrate hexahydrate and nickel chloride hexahydrate.

4. The method of claim 1, wherein, The solvent is N, N-dimethylformamide.

5. The method of claim 1, wherein, The molar ratio of the iron salt, the nickel salt and terephthalic acid is 1-2:1-2:2-4.

6. The method of claim 1, wherein, The mass ratio of FeNi-MOF to dopamine hydrochloride is 8-12:

1.

7. The method of claim 1, wherein, The temperature rising rate in step S3 is 2.5-3.5 DEG C / min.

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