Nitrogen-doped carbon carrier Fenton-like catalyst as well as preparation method and application thereof

Abstract

The invention provides a nitrogen-doped carbon carrier Fenton-like catalyst as well as a preparation method and application thereof, and belongs to the technical field of wastewater treatment. According to the preparation method, nitrogen-containing organic matter aniline is taken as a monomer, ferric trichloride is taken as Lewis acid which can be taken as a catalyst for Friedel-Crafts alkylation reaction and also can be taken as an iron source in a Fenton-like catalyst, and a super-crosslinked polymer precursor containing uniformly dispersed nitrogen element and ferric trichloride is prepared in one step through the Friedel-Crafts alkylation reaction; and roasting the precursor to generate Fe2O3, so as to obtain the nitrogen-doped carbon carrier with uniformly distributed nitrogen elements and the Fenton-like catalyst loaded with Fe2O3 catalytic active species at the same time. The nitrogen distribution in the carbon carrier of the catalyst prepared by the method is more uniform, the electron transfer capability is stronger, and the activation capability of Fe2O3 on H2O2 is improved, so that the degradation rate of the catalyst on pollutants in printing and dyeing wastewater is improved.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a nitrogen-doped carbon-supported Fenton catalyst, its preparation method, and its application. Background Technology

[0002] Dyeing and printing wastewater, characterized by its complex composition, high color intensity, strong toxicity, and poor biodegradability, has become a key and challenging area in industrial wastewater treatment. This type of wastewater not only contains large amounts of residual dyes (such as azo dyes and anthraquinones) and auxiliaries (surfactants, leveling agents, etc.), but also some unreacted raw materials and intermediate products. The pollutants have stable molecular structures, making them difficult to effectively degrade using traditional biological treatment processes. Direct discharge of such wastewater can severely damage aquatic ecosystems, threatening the survival of plants and animals and the safety of human drinking water.

[0003] Current technologies for treating dyeing and printing wastewater mainly include physical, chemical, and biological methods. Physical adsorption methods (such as activated carbon adsorption) can rapidly decolorize, but they only transfer pollutants rather than degrade them. Saturated adsorption materials are prone to secondary pollution, and the treatment cost is high. Biological treatment methods (such as activated sludge processes) are inexpensive and environmentally friendly, but they have poor tolerance to high-concentration, highly toxic dyeing and printing wastewater, and microorganisms are easily inhibited, leading to unstable treatment efficiency and difficulty in meeting effluent standards. Traditional chemical oxidation methods (such as chlorination and ozone oxidation) can destroy the molecular structure of dyes, but they have limitations such as limited oxidation capacity, high selectivity, and the easy generation of toxic byproducts, making it difficult to meet increasingly stringent environmental emission standards.

[0004] Fenton technology, as a highly efficient advanced oxidation technology, leverages the strong oxidizing power of ·OH (hydroxyl radical) (oxidation potential as high as 2.8V) to non-selectively degrade most organic pollutants, demonstrating unique advantages in the treatment of dyeing and printing wastewater. However, it also has significant limitations: firstly, the reaction requires strongly acidic conditions (pH=2-3), necessitating the consumption of large amounts of acid and alkali to adjust the pH in practical applications, increasing treatment costs and easily corroding equipment; secondly, traditional Fenton reagent (Fe... / The reaction rate is fast, but the ·OH group has a short lifespan. The utilization rate is low, and a large amount of iron-containing sludge is easily generated, making subsequent disposal difficult; thirdly, the reaction system is sensitive to pH fluctuations, and the treatment efficiency drops sharply under neutral or weakly alkaline conditions, making it difficult to adapt to the actual working conditions of dyeing and printing wastewater with fluctuating pH.

[0005] To overcome the shortcomings of traditional Fenton technology, Fenton-like technologies have emerged. These technologies replace Fe by using transition metals (Co, Cu, Mn, etc.) or their oxides, or composite catalysts. By introducing external auxiliary methods such as light, electricity, and ultrasound, breakthroughs have been achieved in expanding the reaction pH range, recycling catalysts, improving oxidation efficiency, and reducing sludge volume, making it a research hotspot in the field of advanced treatment of dyeing and printing wastewater. However, existing Fenton-like technologies still face bottlenecks in practical applications: some catalyst preparation processes are complex and costly, making large-scale production difficult; some systems suffer from catalyst loss and deactivation due to the easy covering of active sites by pollutants; and their adaptability to different types of dyeing and printing wastewater (such as high-salt, high-concentration, and recalcitrant dye wastewater) is insufficient, making it difficult to balance treatment efficiency and economy. Summary of the Invention

[0006] The purpose of this invention is to provide a nitrogen-doped carbon-supported Fenton catalyst, its preparation method, and its application. The nitrogen-doped carbon-supported Fenton catalyst is used for dyeing and printing wastewater and has the characteristics of low cost, simple preparation, low catalyst and oxidant dosage, wide pH range (pH=3-10), strong applicability, fast treatment speed, high catalytic activity, and strong stability.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a nitrogen-doped carbon-supported Fenton catalyst, comprising the following steps: Aniline, ferric chloride, a crosslinking agent, and an organic solvent are mixed and subjected to a Friedel-Crafts alkylation reaction to obtain the precursor. The precursor was calcined to obtain a nitrogen-doped carbon-supported Fenton catalyst.

[0008] Preferably, the molar ratio of aniline to ferric chloride is 1:1 to 3.

[0009] Preferably, the crosslinking agent comprises dimethoxymethane; the molar ratio of aniline to the crosslinking agent is 1:1 to 4.

[0010] Preferably, the organic solvent includes 1,2-dichloroethane.

[0011] Preferably, the Friedel-Crafts alkylation reaction comprises reacting at 50°C for 5 hours, followed by reacting at 80°C for 19 hours.

[0012] Preferably, the roasting temperature is 500~700℃ and the time is 4h.

[0013] This invention provides a nitrogen-doped carbon-supported Fenton catalyst prepared by the preparation method described in the above technical solution.

[0014] This invention provides the application of the nitrogen-doped carbon-supported Fenton catalyst described above in the treatment of dyeing and printing wastewater.

[0015] Preferably, the method of application includes the following steps: The pH value of the dyeing and printing wastewater is adjusted by adding a catalyst and hydrogen peroxide to the wastewater for degradation. The catalyst is the nitrogen-doped carbon-supported Fenton catalyst described in the above technical solution.

[0016] Preferably, the concentration of the catalyst in the dyeing and printing wastewater is 0.3~0.5 g / L, the concentration of hydrogen peroxide in the dyeing and printing wastewater is 30~50 mM, and the pH value of the dyeing and printing wastewater is 3~10.

[0017] This invention provides a method for preparing a nitrogen-doped carbon-supported Fenton-like catalyst. Using aniline, a nitrogen-containing organic compound, as a monomer and ferric chloride as a Lewis acid, it serves as both a catalyst for Friedel-Crafts alkylation and an iron source in the Fenton-like catalyst. A hypercrosslinked polymer precursor containing uniformly dispersed nitrogen and ferric chloride is prepared in one step via Friedel-Crafts alkylation. The precursor is then calcined to generate Fe₂O₃, resulting in a nitrogen-doped carbon support with uniform nitrogen distribution and simultaneously loaded with Fe₂O₃ catalytically active species, forming a Fenton-like catalyst. The catalyst prepared by this method exhibits a more uniform nitrogen distribution in the carbon support, stronger electron transfer capacity, and enhanced activation ability of Fe₂O₃ for H₂O₂, thereby improving the catalyst's degradation rate of pollutants in dyeing and printing wastewater.

[0018] The nitrogen-doped carbon-supported Fenton catalyst of this invention possesses better electron transfer capabilities due to the in-situ dispersion of the iron active component and the in-situ doping of nitrogen. Therefore, when the nitrogen-doped carbon-supported Fenton catalyst of this invention is used to treat dyeing and printing wastewater, for 100 mg / L methylene blue wastewater, only a small amount of catalyst (0.4 g / L) and H2O2 (50 mM) need to be added, and the pH value of the wastewater does not need to be adjusted, 100% degradation can be achieved within 15 minutes. It has the characteristics of low cost, simple preparation, small amount of catalyst and oxidant, wide pH range (pH=3-10), fast treatment speed, high catalytic activity, and strong stability, realizing efficient, economical and environmentally friendly treatment of dyeing and printing wastewater, and meeting the needs of practical industrial applications.

[0019] The present invention proposes a feasible strategy for preparing a Fenton-like catalyst by using nitrogen-containing organic aniline as a monomer to synthesize a hypercrosslinked polymer precursor in one step via Friedel-Crafts alkylation reaction, followed by calcination. This strategy can effectively improve the metal loading and the conductivity of the support, thereby enhancing the catalytic performance of the Fenton-like catalyst.

[0020] The results of the examples show that, using methylene blue (MB) as a model pollutant, the degradation experiments demonstrate that the nitrogen-containing Fe2O3 / NC carrier... HCP The rate constant for the degradation of methylene blue by activated H₂O₂ is 0.4732 min⁻¹. -1 It is an undoped nitrogen support Fe2O3 / CHCP (k=0.0159 min) -1 30 times that of ) . The optimal conditions and efficiency for degradation were: [catalyst]0 = 0.4 g / L, [H2O2]0 = 50 mM, initial pH of wastewater 7.32, constant temperature 30 ℃, degradation time 15 min, and the degradation rate reached 100%. Fe2O3 / NC HCP The -2 / H2O2 system has a wide applicable pH range (3-10) and exhibits strong degradation ability even for high concentrations of MB (100-300 mg / L). Quenching experiments and ESR spectroscopy indicate that the active substances present in the system are ·OH and a small amount of ·O2. - . Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the synthesis routes of Fe2O3 / NCHCP-X (X=1, 2, 3, 4) in Example 1 and Fe2O3 / CHCP in Comparative Example 1; Figure 2 X-ray diffraction patterns of Fe2O3 / NCHCP-X (X=1, 2, 3, 4) in Examples 1-2 and Fe2O3 / CHCP in Comparative Example 1; Figure 3 The FT-IR infrared absorption spectra of Fe2O3 / NCHCP-2 in Example 1 and Fe2O3 / CHCP in Comparative Example 1 are shown below. Figure 4 Fe2O3 / NC in Example 1 HCP Fe2O3 / C in -2 and Comparative Example 1 HCP Raman spectra; Figure 5 Fe2O3 / NC in Example 1 HCP Fe2O3 / C in -2(a), (b) and Comparative Example 1 HCP SEM scan images (c) and (d); Figure 6 Fe2O3 / NC in Example 1 HCP Fe2O3 / C in -2(a) and Comparative Example 1 HCP (b) SEM-Mapping diagram; Figure 7 Fe2O3 / NC in Example 1 HCP -2 Transmission electron microscope (TEM) image (a) and high-resolution transmission electron microscope (HRTEM) image (b) at 200 nm; Figure 8 Fe2O3 / NC HCP The magnetization curve (b) of -2 is a magnified view of (a). Figure 9(a) Isothermal nitrogen adsorption-desorption curves for different catalysts, and (b) Pore size distribution diagrams for different catalysts. Figure 10 Fe2O3 / NC HCP XPS full spectrum of Fe2p (a), (b) C1s, (c) O 1s, (d) N 1s, (e) fine XPS spectrum of Fe2p, (f) Fe2O3 / C HCP XPS full spectrum; Figure 11 (a) Degradation curves for different catalysts, (b) corresponding first-order kinetic curves, (c) Fe2O3 / NC HCP Degradation curve of -X, (d) corresponding first-order kinetic curve; Figure 12 For (a)Fe2O3 / C HCP and Fe2O3 / NC HCP -2 Electrochemical impedance spectroscopy and (b) Total organic carbon removal rate curve; Figure 13 For (a) Fe2O3 / NC HCP The effect of the addition amount of H2O2, (b) the corresponding k value bar chart, (c) the effect of the H2O2 addition concentration, (d) the corresponding k value bar chart, (e) the effect of the initial concentration of methylene blue, and (f) the corresponding degradation rate bar chart. Figure 14 (a) The effect of initial pH value of the solution, and (b) the corresponding k-value bar chart; Figure 15 (a) Effect of water bath temperature on methylene blue degradation, (b) Kinetic curves at different temperatures; Figure 16 The effect of inorganic anions on the degradation of methylene blue; Figure 17 (a) Degradation diagram of quenching experiment, (b) corresponding degradation rate, (c) ESR spectrum, (d) UV absorption spectrum during the degradation process of methylene blue; Figure 18 Fe2O3 / NC HCP -2 Possible reaction mechanism for the degradation of methylene blue by activated H2O2; Figure 19 For (a) Fe2O3 / NC HCP -2 Degradation diagram of MB using activated H2O2 in cycles, (b) Degradation rate corresponding to the number of catalyst cycles, Fe2O3 / NC HCP -2 Before and after comparison, (c) FTIR absorption spectrum, (d) XRD spectrum. Detailed Implementation

[0022] In this invention, unless otherwise specified, the raw materials or reagents required for preparation are all commercially available products well known to those skilled in the art.

[0023] This invention provides a method for preparing a nitrogen-doped carbon-supported Fenton catalyst, comprising the following steps: Aniline, ferric chloride, a crosslinking agent, and an organic solvent are mixed and subjected to a Friedel-Crafts alkylation reaction to obtain the precursor. The precursor was calcined to obtain a nitrogen-doped carbon-supported Fenton catalyst.

[0024] In this invention, the molar ratio of aniline to ferric chloride is preferably 1:1 to 3, more preferably 1:2 to 3; and the ferric chloride is preferably anhydrous ferric chloride.

[0025] In this invention, the crosslinking agent preferably includes dimethoxymethane (FDA); the molar ratio of aniline to the crosslinking agent is preferably 1:1 to 4, more preferably 1:2 to 3.

[0026] In this invention, the organic solvent preferably includes 1,2-dichloroethane. This invention does not impose a specific limit on the amount of the organic solvent used; it can be adjusted as needed to ensure the reaction proceeds.

[0027] In this invention, aniline, organic solvent and crosslinking agent are mixed evenly, and then ferric chloride is added to carry out Friedel-Crafts alkylation reaction.

[0028] In this invention, the Friedel-Crafts alkylation reaction preferably includes: reacting at 50°C for 5 hours, followed by reacting at 80°C for 19 hours. This invention uses aniline, a nitrogen-containing organic compound, as a monomer to prepare a hypercrosslinked polymer precursor via Friedel-Crafts alkylation, thereby obtaining the hypercrosslinked polymer while simultaneously dispersing nitrogen and ferric chloride in situ within the hypercrosslinked polymer.

[0029] After completing the Friedel-Crafts alkylation reaction, the present invention preferably evaporates the solvent in the product, and then places the obtained solid sample in a vacuum drying oven at 80 °C for 24 h before calcining.

[0030] In this invention, the calcination temperature is preferably 500~700℃, more preferably 550~650℃, and even more preferably 600℃, and the calcination time is preferably 4h. This invention involves calcining the precursor to oxidize ferric chloride to Fe2O3, transforming the hypercrosslinked polymer into a nitrogen-doped carbon support supporting Fe2O3, thereby obtaining a carbon-supported nitrogen-doped Fenton-like catalyst.

[0031] After calcination, the resulting product was washed with deionized water and dried in a vacuum drying oven at 80 °C for 24 h to obtain a nitrogen-doped carbon-supported Fenton catalyst.

[0032] This invention provides a nitrogen-doped carbon-supported Fenton catalyst prepared by the preparation method described in the above technical solution.

[0033] This invention provides the application of the nitrogen-doped carbon-supported Fenton catalyst described above in the treatment of dyeing and printing wastewater.

[0034] In this invention, the method of application preferably includes the following steps: The pH value of the dyeing and printing wastewater is adjusted by adding a catalyst and hydrogen peroxide to the wastewater for degradation. The catalyst is the nitrogen-doped carbon-supported Fenton catalyst described in the above technical solution.

[0035] In this invention, the concentration of the catalyst in the dyeing and printing wastewater is preferably 0.3~0.5 g / L, more preferably 0.4 g / L; the concentration of hydrogen peroxide in the dyeing and printing wastewater is preferably 30~50 mM, more preferably 40~50 mM; and the pH value of the dyeing and printing wastewater is preferably 3~10, more preferably 5~7.32.

[0036] In this invention, the degradation time is preferably 15-30 min, more preferably 20-25 min.

[0037] The present invention does not have any special limitation on the source of the dyeing and printing wastewater, which can be obtained from sources known in the art.

[0038] In an embodiment of the present invention, a methylene blue aqueous solution is specifically used to simulate dyeing and printing wastewater. The concentration of the methylene blue aqueous solution is preferably 1~300 mg / L, more preferably 100~200 mg / L.

[0039] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0040] Unless otherwise specified, the experimental methods described in the various embodiments of this invention are conventional methods; unless otherwise specified, the reagents and raw materials described below are all commercially available.

[0041] Example 1

[0042] like Figure 1As shown, 0.93 g (0.01 mol) of aniline was weighed into a three-necked flask. 40 mL of DCE (1,2-dichloroethane) and 1.8 mL of FDA (0.01 mol, dimethoxymethane) were measured and added to the flask and mixed thoroughly. Finally, 3.24 g (0.02 mol) of anhydrous FeCl3 was added. The mixture was reacted at 50 °C for 5 h, then heated to 80 °C and reacted for 19 h, yielding a reddish-brown viscous liquid. The solvent in the mixture was evaporated to dryness, and the resulting solid sample was dried in a vacuum drying oven at 80 °C for 24 h. It was then calcined in a muffle furnace at 600 °C for 4 h, washed with deionized water, and dried in a vacuum drying oven at 80 °C for 24 h to obtain Fe2O3 / NC with an aniline:anhydrous FeCl3 molar ratio of 1:2. HCP -2.

[0043] Examples 2-4

[0044] The only difference from Example 1 is that the amount of anhydrous FeCl3 added was changed sequentially to 1.62 g, 4.86 g, and 6.48 g, resulting in Fe2O3 / NC ratios of aniline:anhydrous FeCl3 of 1:1, 1:3, and 1:4, respectively. HCP -1,Fe2O3 / NC HCP -3 and Fe2O3 / NC HCP -4, which are referred to as Examples 2 to 4 in sequence.

[0045] Comparative Example 1

[0046] The only difference from Example 1 is that toluene is used instead of aniline as the monomer, resulting in a nitrogen-free catalyst with a toluene:anhydrous FeCl3 ratio of 1:2, denoted as Fe2O3 / C. HCP .

[0047] Structural characterization and performance testing

[0048] 1. Characterization and Analysis of Catalysts

[0049] 1) XRD characterization

[0050] The types of iron compounds contained in the different catalysts in Examples 1-2 and Comparative Example 1 were characterized by X-ray diffraction.

[0051] Figure 2 The X-ray diffraction patterns are shown for Fe2O3 / NCHCP-X (X=1, 2, 3, 4) in Examples 1 and 2 and Fe2O3 / CHCP in Comparative Example 1; as shown. Figure 2As shown, the observed diffraction peaks are 24.15°, 33.16°, 35.63°, 40.86°, 49.46°, 54.07°, 62.44°, 64.00°, 71.95°, and 75.46°, corresponding to crystal planes (012), (104), (110), (113), (024), (116), (214), (300), (101), and (220), respectively. These crystal planes indicate that the iron compound in the synthesized catalyst is Fe2O3 (PDF#No.87-1166). The figure shows the characteristic peaks of X-ray diffraction of pure Fe2O3, and the characteristic peaks of the synthesized catalyst are basically consistent with those of pure Fe2O3. Compared with pure Fe2O3, Fe2O3 / NC HCP -1,Fe2O3 / NC HCP -2,Fe2O3 / NC HCP -4, Fe2O3 / C HCP The relative intensity of the (104) crystal plane is slightly higher than that of (110), which may be due to the preferred orientation of the crystal plane when Fe2O3 is formed during the synthesis process. However, this characterization can still indicate the successful synthesis of the catalyst.

[0052] 2) FTIR characterization

[0053] Figure 3 The FT-IR infrared absorption spectra of Fe2O3 / NCHCP-2 in Example 1 and Fe2O3 / CHCP in Comparative Example 1 are shown below; Figure 3 As shown, at 1120 cm -1 and 557 cm -1 The absorption peaks at 3420 cm⁻¹ correspond to the vibrational absorption peaks of CO and Fe-O, respectively, further confirming the presence of Fe₂O₃ in the catalyst. -1 The strong absorption peak at the point corresponds to the -OH group, which is generated by water molecules absorbed by the catalyst surface, indicating that the prepared catalyst is hydrophilic and easy to disperse in wastewater.

[0054] 3) Raman characterization

[0055] Figure 4 Fe2O3 / NC in Example 1 HCP Fe2O3 / C in -2 and Comparative Example 1 HCP Raman spectra; such as Figure 4 As shown, Fe2O3 / NC HCP -2 and Fe2O3 / C HCP Having similar Raman absorption spectra at 1383 cm⁻¹ -1 and 1592 cm -1 The two peaks appearing at 1383 cm⁻¹ are the most common peaks in carbon materials. -1The peak at that point is due to the presence of sp in the carbon material. 3 The defects and disorder in the carbon rings cause what is called the D-band; and the area located at 1592 cm⁻¹... -1 The peak at that point is due to the scattering of first-order phonons, corresponding to sp in carbon materials. 2 Carbon atoms, called the G band. The peak height ratio of the D and G bands (I D / I G It is commonly used to estimate the defects and disorder of graphitized structures, as well as sp. 3 / sp 2 The ratio of bonded carbon atoms. Calculations show that the Fe₂O₃ / C ratio... HCP I D / I G The value is 0.82. With the incorporation of nitrogen heteroatoms, Fe2O3 / NC HCP -2 of I D / I G The increase to 0.90 indicates that nitrogen doping is beneficial to improving the defect level of carbon materials, which will help to increase the electron transfer rate in catalytic reactions.

[0056] 4) SEM scanning and SEM-Mapping scanning

[0057] Figure 5 Fe2O3 / NC in Example 1 HCP Fe2O3 / C in -2(a), (b) and Comparative Example 1 HCP SEM scan images (c) and (d); as shown Figure 5 As shown in (a~d), the carbon skeleton of the precursor will collapse to a certain extent during the calcination process, but the resulting catalyst can still maintain a certain layered structure. Figure 5 (a) and (b) show that Fe2O3 / NC HCP The -2 surface has an irregular layered structure with distinct boundaries. Numerous irregular needle-like structures are dispersed within this layered structure, providing attachment sites for reactants and thus facilitating catalytic reactions. In contrast, such as Figure 5 As shown in (c) and (d), Fe2O3 / C HCP The surface has many irregular porous structures and is also covered with a large amount of blocky material, resulting in poor mass transfer and catalytic effects.

[0058] To determine the elemental composition and distribution on the catalyst, the Fe2O3 / C... HCP and Fe2O3 / NC HCP -2 Perform SEM-mapping scan.

[0059] Figure 6 Fe2O3 / NC in Example 1 HCP Fe2O3 / C in -2(a) and Comparative Example 1 HCP(b) SEM-Mapping image, where the SEM scale bar in (a) is 6μm and the SEM scale bar in (b) is 4μm; Figure 6 As shown, Fe2O3 / NC HCP In the catalyst, C, Fe, O, and N elements are uniformly distributed. Semi-quantitative elemental analysis results show that the Fe₂O₃ / C ratio... HCP The percentages of oxygen and iron atoms are 17.96% and 5.34%, respectively, Fe2O3 / NC HCP The percentages of oxygen and iron atoms in Fe2O3 / NC increased to 21.76% and 9.81%, respectively, while the percentage of nitrogen atoms remained at 7.67%. Under the same synthesis conditions, Fe2O3 / NC HCP The higher Fe2O3 content in -2 indicates that using N-containing monomers is beneficial for loading more Fe2O3.

[0060] 5) TEM characterization

[0061] Figure 7 Fe2O3 / NC in Example 1 HCP -2 Transmission electron microscopy (TEM) image (a) and high-resolution TEM image (b) at 200 nm; as shown Figure 7 As shown in (a), a large number of irregular spherical Fe2O3 particles are densely dispersed in NC. HCP Within the lamellae, this indicates the successful preparation of a supported Fenton-like catalyst. Figure 7 The high-resolution transmission electron microscopy image in (b) shows clear lattice fringes, further confirming the excellent crystal quality of Fe2O3. The fringes with lattice distances of 0.2207 nm, 0.1841 nm and 0.2292 nm correspond to the (113), (110) and (024) crystal planes of Fe2O3, respectively.

[0062] 6) VSM Testing

[0063] The intrinsic magnetic properties of iron-based heterogeneous catalysts play a crucial role in their separation and recovery. The Fe2O3 / NC ratio in Example 1 was tested using VSM. HCP -2 Magnetic properties of catalyst, Figure 8 Fe2O3 / NC HCP The magnetization curve of -2, (b) is a magnified view of (a); as Figure 8 As shown, from the hysteresis loop ( Figure 8 From (a) we can calculate that the saturation magnetization (Ms) of the material is 6.14 emu / g. The prepared catalyst exhibits high ferromagnetism, and under the action of an external magnetic field, it can be rapidly separated from the solution, which is beneficial to the catalyst recovery process. Lattice defects in the sample may hinder the rotation of atomic magnetic moments, resulting in high coercivity (Hc,111 Oe, Figure 8 (b) This is consistent with the results of Raman characterization.

[0064] 7) Isothermal nitrogen adsorption-desorption test

[0065] The prepared catalyst was subjected to isothermal nitrogen adsorption-desorption tests to investigate its specific surface area and pore structure characteristics.

[0066] Figure 9 (a) Isothermal nitrogen adsorption-desorption curves for different catalysts, and (b) pore size distribution diagrams for different catalysts; Figure 9 As shown, the isothermal nitrogen adsorption and desorption curves of the prepared catalyst exhibit a significant hysteresis loop, displaying type IV curves. This indicates that all prepared catalysts possess a mesoporous structure, which is beneficial for mass transfer during the catalytic reaction. Calculations yielded the Fe2O3 / C... HCP Its specific surface area is 5.113 m². 2 / g,Fe2O3 / NC HCP -1,Fe2O3 / NC HCP -2,Fe2O3 / NC HCP -3 and Fe2O3 / NC HCP The specific surface area of ​​-4 is 3.890 m². 2 / g, 9.157 m 2 / g, 16.267 m 2 / g and 65.089 m 2 / g. The results showed that the specific surface area of ​​the catalyst increased with increasing FeCl3 content. The average pore size of the prepared catalysts was mesoporous (2-50 nm), with specific data showing Fe2O3 / C HCP (19.061 nm), Fe2O3 / NC HCP -1 (25.342 nm), Fe2O3 / NC HCP -2 (12.364 nm), Fe2O3 / NC HCP -3 (8.046 nm), Fe2O3 / NC HCP -4 (12.649 nm).

[0067] 8) XPS characterization

[0068] Fe2O3 / NC was analyzed using XPS testing. HCP -2 Surface elemental composition and chemical state; Figure 10 Fe2O3 / NC HCP XPS full spectrum of Fe 2p (a), (b) C 1s, (c) O 1s, (d) N 1s, (e) XPS fine spectrum of Fe 2p, (f) Fe2O3 / C HCPXPS full spectrum; like Figure 10 As shown, the full spectrum Figure 10 Image (a) shows that the peaks at 710.64 eV, 530.75 eV, 399.47 eV, and 284.13 eV correspond to Fe, O, N, and C, respectively, indicating the successful synthesis of the catalyst. Figure 10 In the fine spectrum of C1s in (b), the characteristic peak signals are located at 284.1 eV, 285.3 eV, and 287.5 eV, respectively, corresponding to C1s(sp) 2 ), CN(sp 2 ) and CN(sp 3 The XPS fine spectrum of C1s indicates Fe2O3 / NC HCP -2 contains CN bonds with different hybridization modes. After calculation, sp 2 The hybridization rate was 12.4%, sp 3 The hybridization rate was 11.6%. Figure 10 In the fine spectrum of (c)O1s, the fitted peak signals are attributed to lattice oxygen (529.3 eV, O) respectively. 2- ) and OH (530.8 eV). The lattice oxygen can be attributed to Fe2O3, and the presence of OH may be due to the absorption of moisture on the catalyst surface.

[0069] according to Figure 10 The fine spectrum of (d)N1s shows that the characteristic peaks at 398.07 eV, 399.07 eV, and 399.9 eV belong to pyridine nitrogen, pyrrole nitrogen, and graphitic nitrogen, respectively, with contents of 17.75%, 21.55%, and 58.17%. Furthermore, the peak at 398.7 eV can be attributed to Fe-N, indicating that iron and nitrogen formed a chemical bond during catalyst synthesis, which helps reduce metal dissolution during catalyst use. The fine spectrum of Fe2p (…) Figure 10 (e) is characterized by the splitting of spin orbitals into Fe2p 3 / 2 and Fe2p 1 / 2 Two parts, located at 710.5 eV in Fe2p 3 / 2 Peak and Fe2p at 723.6 eV 1 / 2 Peak attributed to Fe 2+ Fe2p located at 713.2 eV 3 / 2 Peak and Fe2p at 725.6 eV 1 / 2 Peak attributed to Fe 3+ The two peaks at 732.1 eV and 718.4 eV are Fe. 3+ The satellite peak. Figure 10 (f) shows that Fe2O3 / C HCPIn the XPS semi-quantitative atomic analysis results, the percentages of O atoms and Fe atoms were 22.27% and 2.82%, respectively, and the Fe2O3 / NC ratio was [not specified]. HCP The percentages of O atoms and Fe atoms in Fe2O3 / NC are 25.04% and 7.75%, respectively. HCP The percentage of O atoms and Fe atoms in -2 is compared to Fe2O3 / C. HCP High, which is consistent with the characterization results of EDX.

[0070] 2. Catalytic performance and mechanism

[0071] Catalytic degradation experiment of methylene blue (MB): 100 mL of simulated methylene blue wastewater (20 mg / L) was measured into a 250 mL beaker. The beaker was placed in a thermostatically heated magnetic stirrer, maintaining the water bath temperature at 30 ± 0.5 ℃. A certain amount of catalyst was weighed and added to the beaker, and stirring was started to ensure uniform dispersion of the catalyst in the wastewater. A certain amount of H2O2 was weighed and added to the beaker to initiate the reaction. Timing was started, and 3 mL of wastewater was taken from the beaker at regular time intervals and filtered through a 0.45 μm filter membrane. The absorbance of the filtered wastewater was immediately measured at a wavelength of 550 nm using a UV-Vis spectrophotometer. No oxidant was added in the adsorption experiment, and other operating procedures were the same as above.

[0072] Under normal circumstances, the initial pH of the methylene blue wastewater is not adjusted in the degradation experiment (the concentration is 20 mg / L, and the pH of the unadjusted methylene blue wastewater is 5.00). If necessary, the initial pH of the solution is adjusted using 0.1 M HCl or 0.1 M NaOH.

[0073] 2.1) Comparison of degradation effects of different catalysts

[0074] Methylene blue, a typical cationic dye, was selected as the model pollutant, and H2O2 was used as the oxidant to test the catalytic degradation performance of different prepared catalysts.

[0075] Figure 11 (a) Degradation curves for different catalysts, (b) corresponding first-order kinetic curves, (c) Fe2O3 / NC HCP Degradation curve of -X, (d) corresponding first-order kinetic curve (reaction conditions: [catalyst]0 = 0.40 g / L, [H2O2]0 = 50 mM, [MB]0 = 100 mg / L, pH 7.32, 30 ℃).

[0076] like Figure 11As shown in Figure (a), when only H2O2 was added to the degradation system, only 13.65% of methylene blue was degraded within 15 minutes, indicating that H2O2 can self-decompose to produce active substances to degrade methylene blue, but the degradation rate is slow. Adding Fe2O3 nanoparticles and H2O2 to the degradation system resulted in a degradation rate of 13.75% within 15 minutes, indicating that Fe2O3 nanoparticles could not effectively activate H2O2 to degrade methylene blue in this system. A possible reason is that the concentration of methylene blue in this system was high, and the Fe2O3 nanoparticles were covered by the pollutant, preventing the active sites from activating H2O2. Adding Fe2O3 / C to the degradation system... HCP With H2O2, the degradation rate within 15 minutes was 21.75%, indicating that Fe2O3 / C HCP It possesses some catalytic degradation ability, but the catalytic effect is weak. Fe2O3 / C HCP The medium-carbon support disperses Fe2O3, and the exposed active sites can activate H2O2 to degrade methylene blue. Fe2O3 / NC is also added to the system. HCP When exposed to H2O2, methylene blue is rapidly degraded, reaching 100% degradation within 15 minutes.

[0077] The degradation reaction follows a pseudo-first-order reaction model, Fe2O3 / NC HCP The rate constant for the degradation of methylene blue by activated H₂O₂ is 0.4732 min⁻¹. -1 It is Fe2O3 / C HCP (k=0.0159min) -1 30 times that of Fe2O3. As mentioned earlier, carbon supports are beneficial for improving the catalytic activity of Fe2O3, and further doping of nitrogen elements into carbon supports is even more beneficial for improving the catalytic degradation performance of Fenton-like catalysts. Among the catalysts synthesized with different ratios of aniline to FeCl3, the Fe2O3 / NC ratio is 30 times higher. HCP The catalytic degradation effect of Fe2O3 / NC was the best. The degradation rates of other catalysts within 15 minutes were as follows: Fe2O3 / NC HCP -1 (63.38%), Fe2O3 / NC HCP -3 (99.39%), Fe2O3 / NC HCP -4 (64.10%), such as Figure 11 As shown in (c). In summary, the Fenton-like catalysts prepared using the nitrogen-containing monomer aniline can effectively catalyze the degradation of methylene blue by H2O2.

[0078] 2.2) Measurement of Fe2O3 / C HCP With Fe2O3 / NC HCP Electrochemical impedance spectroscopy of -2, Figure 12 For (a)Fe2O3 / C HCPand Fe2O3 / NC HCP -2 Electrochemical impedance spectroscopy and (b) Total organic carbon removal rate curve (reaction conditions: [catalyst]0 = 0.40 g / L, [H2O2]0 = 50 mM, [MB]0 = 100 mg / L, pH 7.32, 30℃); like Figure 12 As shown in (a), Fe2O3 / NC HCP The radius of the arc at -2 is less than Fe2O3 / C. HCP The smaller radius of the arc indicates that the nitrogen-containing catalyst has better electrical conductivity, lower charge transfer resistance, and a faster electron transfer rate. Nitrogen doping can adjust the local electronic structure of surrounding carbon by controlling the spin density and charge distribution of the carbon lattice, increasing the electron cloud density (electronegativity: χ) of adjacent carbon atoms. N = 3.04 > χ C = 2.55), significantly improving the performance of carbon catalysts. Furthermore, as the XPS characterization above indicates, Fe2O3 / NC HCP -2 contains structures such as graphitic nitrogen, pyridine nitrogen, and pyrrole nitrogen. The atomic radius and bond length of nitrogen atoms differ from those of carbon atoms. Nitrogen modification can alter the morphology and degree of defects in carbon materials, effectively disrupting sp... 2 The inertness of the hybrid carbon lattice increases the number of reaction sites. Therefore, Fenton-like catalysts prepared using nitrogen-containing monomers exhibit better catalytic degradation performance.

[0079] In addition, Fe2O3 / NC was analyzed by total organic carbon. HCP The mineralization ability of the -2 / H2O2 system for methylene blue. For example... Figure 12 As shown in (b), under these experimental conditions, the mineralization rate of methylene blue decreased rapidly within 10 minutes, and the mineralization rate slowed down after 10 minutes, reaching 59.57% at 60 minutes. This phenomenon indicates that Fe2O3 / NC HCP The -2 / H2O2 system exhibits strong mineralization ability for methylene blue in the early stages of the reaction. The subsequent decrease in mineralization ability is likely due to the depletion of H2O2, preventing the formation of further active substances to oxidize methylene blue. This also suggests that in practical applications, increasing the Fe2O3 / NC ratio can help. HCP The method of using -2 and H2O2 to achieve complete mineralization of pollutants.

[0080] 2.3) Influence of operating parameters

[0081] 2.3.1 In the Fenton-like reaction, the generation of active species is closely related to the amount of catalyst added and the concentration of H2O2. Therefore, to facilitate subsequent experiments under optimal degradation conditions, the operating parameters were optimized. The study investigated Fe2O3 / NC... HCP-2 Effect of addition amount on methylene blue degradation

[0082] Figure 13 For (a) Fe2O3 / NC HCP (a) Effect of addition amount of -2, (b) corresponding k value bar chart, (c) Effect of addition concentration of H2O2, (d) corresponding k value bar chart, (e) Effect of initial concentration of methylene blue, (f) corresponding degradation rate bar chart (reaction conditions: [catalyst]0 = 0.40 g / L, [H2O2]0 = 50 mM, [MB]0 = 100 mg / L, pH 7.32, 30℃).

[0083] like Figure 13 As shown in (a), Fe2O3 / NC HCP When the addition amount of methylene blue was increased from 0.2 g / L to 0.4 g / L and the reaction time was 10 minutes, the degradation rate of methylene blue increased from 90% to 100%, and the k value increased from 0.1744 min. -1 Increased to 0.4732 min -1 With Fe2O3 / NC HCP The increased addition of Fe2O3 provides more active sites for the catalytic reaction, accelerating the effective decomposition of H2O2 and promoting the degradation reaction. HCP When the addition of -2 was further increased from 0.4 g / L to 0.6 g / L and 0.8 g / L, the k value increased to 0.8037 min. -1 and 0.8584 min -1 ( Figure 13 (b)). In summary, when Fe2O3 / NC HCP When the addition amount of Fe2O3 is 0.4 g / L, the degradation rate can reach 100% within 10 minutes. Therefore, considering cost-saving, subsequent experiments will choose Fe2O3 / NC. HCP The addition amount of -2 is 0.4 g / L.

[0084] like Figure 13 As shown in Figure (c), the effect of increasing the initial H₂O₂ concentration from 10 mM to 100 mM on the degradation of methylene blue was investigated. When the initial H₂O₂ concentration was increased sequentially from 10 mM, 25 mM, 40 mM to 50 mM, and the degradation time was 15 minutes, the degradation rates of methylene blue were 83.0%, 95.6%, 97.2%, and 100%, respectively, with corresponding k values ​​(…). Figure 13 The mean (d) was 0.0981 min. -1 0.1596 min -1 2507 min -1 and 0.4732 min-1 This phenomenon is attributed to the fact that higher concentrations of H₂O₂ provide more reactants for the catalytic reaction, which is kinetically favorable for the degradation of methylene blue. When the initial H₂O₂ concentration increased from 50 mM to 60 mM, 70 mM, and 100 mM, the degradation rates of methylene blue at 15 minutes were 100%, 97.0%, and 96.3%, respectively. During the Fenton reaction, excess H₂O₂ reacts with ·OH and Fe₂O₃. 3+ Side reactions occur, generating free radicals (·O2H) with low redox potentials, as shown in equations (3.1) and (3.2), which inhibit the degradation of methylene blue. Therefore, in this degradation system, an H2O2 dosage of 50 mM is most suitable.

[0085] (3.1) (3.2) In addition, the effect of the initial concentration of methylene blue on the degradation rate is as follows: Figure 13 As shown in Figure (e), when the methylene blue concentration was increased sequentially from 100 mg / L to 150 mg / L, 200 mg / L, and 300 mg / L, and the reaction time was 15 minutes, the degradation rate decreased from 100% to 95.23%, 93.68%, and 91.28%, respectively. Under certain degradation conditions, increasing the pollutant concentration requires a larger amount of catalyst and oxidant to completely remove the pollutant. In this part of the study, the pollutant concentration was controlled to increase several times over, but the degradation rate did not decrease significantly, indicating that Fe2O3 / NC HCP The -2 / H2O2 system has a strong ability to remove methylene blue.

[0086] 2.3.2 The application of traditional Fenton degradation is limited because it can only be carried out under acidic conditions (pH = 3). The development of Fenton-like technologies has overcome this limitation. This study investigates the effect of the initial pH of wastewater on the degradation of methylene blue. Figure 14 (a) Effect of initial pH of solution, (b) corresponding histogram of k values ​​(reaction conditions: [catalyst]0 = 0.40 g / L, [H2O2]0 = 50 mM, [MB]0 = 100 mg / L, 30 ℃).

[0087] like Figure 14 As shown, Fe2O3 / NC HCPThe -2 / H2O2 system exhibits strong degradation ability for methylene blue within an initial pH range of 3–10, overcoming the limitations of traditional Fenton's method and successfully expanding the working pH range of Fenton-like technology. Furthermore, the degradation rate of methylene blue is fastest without adjusting the initial pH of the wastewater; therefore, the initial pH of the solution was not adjusted in subsequent experiments. An initial pH of 11 significantly inhibits the degradation reaction, possibly because H2O2 is easily decomposed into H2O and O2 in alkaline solutions. 2， This ultimately leads to a decrease in the catalytic efficiency of the system.

[0088] 2.3.3 Effect of temperature change on methylene blue degradation: Figure 15 (a) Effect of water bath temperature on the degradation of methylene blue, (b) Kinetic curves at different temperatures (reaction conditions: [catalyst]0=0.40 g / L, [H2O2]0=50 mM, [MB]0=100 mg / L, pH 7.32).

[0089] like Figure 15 As shown, the reaction temperature affects Fe2O3 / NC HCP The -2 / H2O2 system has a certain impact on the degradation of methylene blue. When the temperature is increased sequentially from 15 ℃ to 20 ℃, 25 ℃, 30 ℃, and 35 ℃, and the reaction time is 15 minutes, the degradation rates are 90.61%, 91.34%, 100%, 100%, and 100%, respectively. The higher the temperature, the faster the degradation curve declines, indicating a faster degradation rate. Temperature affects the molecular motion rate of reactants; higher temperatures increase molecular motion rates and the probability of collisions between reactants, thus favoring the catalytic reaction. However, excessively high temperatures can cause H2O2 to decompose spontaneously. To eliminate the influence of H2O2 decomposition on this experiment, the maximum reaction temperature should be controlled at 35 ℃.

[0090] The degradation reaction conforms to the pseudo-first-order kinetic model. The apparent rate constant at each temperature can be obtained according to equation (2.4). Then, according to the Arrhenius equation (Equation 3.3), the apparent activation energy of the system can be calculated to be 63.293 kJ / mol, which belongs to the reaction-controlled type.

[0091] lnk = - + lnA (3.3)

[0092] Where T (K) is the reaction temperature, Ea (kJ / mol) is the apparent activation energy, k is the apparent efficiency constant, A is the pre-exponential factor, and R = 8.314 (J / (mol·K)).

[0093] 2.3.4 Effect of Inorganic Anions

[0094] Actual wastewater environments are complex and contain various interfering substances. Therefore, to investigate the anti-interference properties of Fenton-like systems, common inorganic anions in wastewater, such as dihydrogen phosphate ions (H₂PO₄²⁻), were selected. - ), bicarbonate ions (HCO3) 2- ), chloride ions (Cl) - ), nitrate ions (NO3) - ) and sulfate ions (SO4) 2- Anti-interference tests were conducted using Fe2O3 / NC as the interfering agent. HCP -2 catalyst.

[0095] Figure 16 The effect of inorganic anions on the degradation of methylene blue (reaction conditions: [catalyst]0 = 0.40 g / L, [H2O2]0 = 50 mM, [MB]0 = 100 mg / L, pH 7.32, 30 ℃, anion concentration of 5 mM).

[0096] like Figure 16 As shown, Cl - NO3 - and SO4 2- It has little effect on the degradation of methylene blue. H2PO4 - and HCO3 2- The presence of these two ions significantly impacts the degradation of methylene blue; at 15 minutes, the degradation rates of methylene blue are only 16.67% and 12.87%, respectively. The inhibition of the degradation reaction by these two ions may be due to H₂PO₄. - and HCO3 2- Both are free radical scavengers, and the reactions are shown in equations (3.4) and (3.5), which reduce the ·OH groups in the system and inhibit the degradation reaction. In addition, in the composite material Fe2O3 / NC... HCP In this process, Fe2O3 exhibits high reactivity after combining with a nitrogen-containing support, while H2PO4 is present in the solution. - Easily interacts with Fe2O3 / NC HCP Surface chelation occurs, occupying active sites and limiting the catalytic reaction. [100, 101] .

[0097] (3.4) (3.5) 2.4) Discussion on the catalytic degradation mechanism To investigate Fe2O3 / NC HCP-2 The active substances generated by activating H2O2 were subjected to quenching experiments. According to literature reports, the most likely active substances generated in Fenton-like systems using H2O2 as an oxidant are: OH and ·O2 - tert-Butanol (TBA) can be used as... Effective OH remover, p-benzoquinone ( p -BQ) can be used as O2 - The removal agent was added to the degradation system, and the changes in degradation rate were observed.

[0098] Figure 17 The images show (a) the degradation curve of the quenching experiment, (b) the corresponding degradation rate, (c) the ESR spectrum, and (d) the UV absorption spectrum of the methylene blue degradation process (reaction conditions: [catalyst]0 = 0.40 g / L, [H2O2]0 = 50 mM, [MB]0 = 100 mg / L, pH 7.32, 30 ℃, quencher concentration 50 mM). Fe2O3 / NC HCP -2 catalyst.

[0099] like Figure 17 As shown in (a), after adding TBA to the degradation system, the removal rate of methylene blue was only 15.9%, indicating that... OH is the main active substance for removing methylene blue. After adding BQ to the degradation system, the removal rate of methylene blue decreased slightly (89.7%), indicating the presence of a small amount of ·O2 in the system. - It also plays a minor role in the degradation of methylene blue.

[0100] To further confirm the types of active substances, ESR spectroscopy was performed to simulate the degradation process. The free radical scavenger DMPO was used to target the degradation system. OH and ·O2 - The signals of DMPO-OH and DMPO-O2 were captured and detected to obtain ESR spectra, such as... Figure 17 As shown in (b), the DMPO-OH complex signal is strong, while the DMPO-O2 signal is weak, and the detection results are consistent with the free radical removal experiment results. In summary, Fe2O3 / NC HCP -2 The main active substances produced by activating H2O2 are OH, and a small amount of O2 - . OH radicals possess a high redox potential, allowing them to indiscriminately attack chemical bonds, which is beneficial for the degradation of methylene blue. Furthermore, the ultraviolet absorption spectra during the degradation process of methylene blue were monitored. For example... Figure 17As shown in (d), during the degradation experiment, the characteristic absorption peak at 664 nm gradually decreased over time, and the color of the solution gradually changed from dark blue to colorless, directly indicating the degradation of methylene blue.

[0101] Therefore, the possible reaction mechanism is inferred as shown in equations (3.6)-(3.8), and the mechanism is as follows: Figure 18 As shown.

[0102] (3.6) (3.7) (3.8) 2.5) Catalyst stability Recyclability is one of the characteristics of Fenton-like catalysts; this study explores Fe2O3 / NC HCP The reusability and stability of the catalyst were assessed. Used catalysts were collected, washed, and dried before being used in further testing and degradation. The recovered catalysts were then used in degradation experiments.

[0103] Figure 19 For (a) Fe2O3 / NC HCP -2 Degradation diagram of MB using activated H2O2 in cycles, (b) Degradation rate corresponding to the number of catalyst cycles, Fe2O3 / NC HCP -2 Before and after comparison, (c) FTIR absorption spectrum, (d) XRD spectrum; like Figure 19 As shown in (a) and (b), with increasing usage, Fe2O3 / NC HCP The catalytic degradation performance of Fe2O3 also decreased with use. The degradation rate of methylene blue was 80.50% during the second use, but only 61.20% during the third use, indicating poor recycling efficiency. The likely reason is that Fe2O3 / NC... HCP The specific surface area of ​​the catalyst is relatively small, and during recycling, the pores of the catalyst are easily blocked by intermediates generated during degradation, resulting in a decrease in degradation performance. In addition, the concentration of the methylene blue solution is relatively high, and the intermediates generated during degradation can easily cover the active sites of the catalyst, causing a decrease in the catalyst's degradation ability during repeated use.

[0104] Fe2O3 / NC after one use HCP -2 FTIR and XRD tests were performed, and the results were compared with the FTIR and XRD spectra of the unused catalyst. The comparison results are as follows: Figure 19 As shown in (c) and (d), the infrared absorption peak positions of the catalyst before and after use are basically the same, around 1120 cm⁻¹. -1 and 557 cm-1 The absorption peaks at this point can be attributed to CO and Fe-O bonds, with little change in peak shape and intensity. Similarly, the X-ray diffraction peak positions of the catalyst before and after use are basically the same, indicating that the main iron species in the catalyst after use is still Fe2O3, suggesting that Fe2O3 / NC HCP -2 exhibits good stability, with the catalyst composition remaining essentially unchanged before and after use. The reduced performance after repeated use is likely due to the small specific surface area of ​​the catalyst, which leads to pore blockage and coverage of active sites.

[0105] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a nitrogen-doped carbon support Fenton-like catalyst, characterized in that, The method comprises the following steps: aniline, ferric chloride, a cross-linking agent and an organic solvent are mixed to perform a Friedel-Crafts alkylation reaction to obtain a precursor; the precursor is calcined to obtain a nitrogen-doped carbon support Fenton-like catalyst.

2. The production method according to claim 1, characterized by, The molar ratio of the aniline to the ferric chloride is 1:1-3.

3. The production method according to claim 1 or 2, characterized by, The cross-linking agent comprises dimethoxymethane; the molar ratio of the aniline to the cross-linking agent is 1:1-4.

4. The production method according to claim 1, characterized by, The organic solvent comprises 1,2-dichloroethane.

5. The preparation method according to claim 3, characterized in that, The Friedel-Crafts alkylation reaction comprises: 5 h of reaction at 50℃ and 19 h of reaction at 80℃.

6. The production method according to claim 5, wherein The calcination temperature is 500-700℃, and the time is 4 h.

7. The nitrogen-doped carbon support Fenton-like catalyst prepared by the preparation method in any one of claims 1-6.

8. Application of the nitrogen-doped carbon support Fenton-like catalyst in claim 7 to treatment of printing and dyeing wastewater.

9. Use according to claim 8, characterized in that, The application method comprises the following steps: adjusting the pH value of the printing and dyeing wastewater, adding the catalyst and hydrogen peroxide into the printing and dyeing wastewater, and performing degradation; The catalyst is the nitrogen-doped carbon support Fenton-like catalyst in claim 7.

10. Use according to claim 9, characterized in that, The concentration of the catalyst in the printing and dyeing wastewater is 0.3-0.5 g / L, the concentration of the hydrogen peroxide in the printing and dyeing wastewater is 30-50 mM, and the pH value of the printing and dyeing wastewater is 3-10.

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