Preparation method and application of carbon-nitrogen-sulfur doped cobalt ferrite modified mesoporous silicon catalyst

Abstract

This invention discloses a method for preparing and applying a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst. The method involves sequentially adding an alkyl quaternary ammonium salt, anhydrous ethanol, ammonium hydroxide, and an inorganic silicon source to water, stirring until homogeneous, and allowing natural precipitation. After separating the precipitate and removing the template agent, the precipitate is washed and dried to obtain mesoporous silica. The mesoporous silica, cobalt ferrite particles, and sulfur-containing amino acids are then thoroughly ground and calcined under a protective gas atmosphere to obtain the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst. The material prepared by this invention has the advantages of simple preparation and convenient operation. Furthermore, based on the synergistic effect of carbon, nitrogen, sulfur, and cobalt ferrite, it can further enhance the electron transfer rate and improve the activation efficiency for persulfate. In sulfonamide antibiotic removal systems, it exhibits advantages such as high degradation efficiency, short degradation time, low catalyst and persulfate dosage, and wide pH adaptability.

Description

Technical Field

[0001] This invention belongs to the field of preparation and application technology of mesoporous silica-derived catalysts, and specifically discloses a method for preparing and applying a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst. Background Technology

[0002] Sulfonamide antibiotics are a class of drugs widely used to treat diseases and infections in humans and animals. However, due to the limited removal capabilities of existing wastewater treatment plants, sulfonamide antibiotics have been frequently detected in secondary effluents, groundwater, and surface water in recent years. Because sulfonamide antibiotics have long half-lives, biotoxicity, and bioaccumulation, they pose a serious threat to human health and aquatic life; therefore, it is urgent to develop effective methods to remove sulfonamide antibiotics from water.

[0003] Advanced oxidation processes based on persulfate are widely used in the removal of sulfonamide antibiotics due to their simplicity, safe and convenient transportation, and strong oxidizing properties. Spinel cobalt ferrite, with its strong magnetization and low cost, is considered one of the better materials for activating persulfate. Doping with non-metallic elements such as carbon, nitrogen, or sulfur can accelerate electron transfer during the reaction process, improve the activation efficiency of the catalyst for persulfate, and thus increase the degradation efficiency of sulfonamide antibiotics. However, because cobalt ferrite is prone to aggregation, the number of active sites is reduced, resulting in unsatisfactory degradation efficiency of persulfate activated by carbon, nitrogen, or sulfur doping for sulfonamide antibiotics. Problems include low degradation efficiency, excessively long degradation time, excessive catalyst and persulfate dosage, and a narrow pH range. Mesoporous silica molecular sieves have a large specific surface area, abundant and regular pore structure, and strong chemical stability, making them ideal catalyst supports. However, current methods for preparing modified mesoporous silica mostly use hydrothermal methods and co-precipitation methods, which often suffer from complex operation, excessive waste generation, and long synthesis cycles. Therefore, selecting a suitable and simple loading method to simultaneously load non-metallic and bimetallic cobalt ferrite materials onto mesoporous silica molecular sieve materials to improve the activation efficiency for persulfate, thereby enhancing the removal efficiency for sulfonamide antibiotics, has strong practical significance for the research on the removal of sulfonamide antibiotics in the aquatic environment and for expanding the application of mesoporous silica materials in the field of water pollution control. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, the present invention aims to provide a method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst. This method addresses the problems of low degradation efficiency, excessively long degradation time, excessive catalyst and persulfate dosage, and narrow pH applicability of existing mesoporous silica catalysts in the process of activating persulfate to degrade sulfonamide antibiotics. A second objective of the present invention is to provide an application of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst in the removal of organic pollutants, such as sulfonamide antibiotics.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst, characterized by comprising the following steps:

[0007] 1): Add alkyl quaternary ammonium salt, anhydrous ethanol, ammonium hydroxide and inorganic silicon source to water, stir evenly and let stand;

[0008] 2): Separate the white solid obtained by natural precipitation after standing, remove the alkyl quaternary ammonium salt, and obtain mesoporous silica material after washing and drying;

[0009] 3): Place the mesoporous silica material, cobalt ferrite particles, and sulfur-containing amino acids into a mortar and grind them for the required time.

[0010] 4): The ground material is calcined in a protective atmosphere to obtain carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst.

[0011] Further, in step 1), the mass ratio of alkyl quaternary ammonium salt to water is 0.325~0.45:50, and the volume ratio of anhydrous ethanol, ammonium hydroxide, inorganic silicon source and water is 20~28:7~9:1.5~2.5:70~90.

[0012] Furthermore, in step 1), the stirring time is 30 min to 120 min, and the settling time is 12 to 20 h.

[0013] Furthermore, the method for removing alkyl quaternary ammonium salt in step 2) is any one of solvent reflux method, calcination method or microwave method.

[0014] Further, in step 3), the mass ratio of mesoporous silica, cobalt ferrite, and sulfur-containing amino acids is 0.5:0.70~0.25:0.25~0.70.

[0015] Furthermore, in step 3), the grinding time in the mortar is 30~90 minutes.

[0016] Furthermore, in step 4), calcination is carried out under a nitrogen atmosphere at a temperature of 500-600°C, a heating rate of 2-5°C / min, and a holding time of 3.5-6.5h.

[0017] An application of a carbon, nitrogen, sulfur-doped cobalt ferrite-modified mesoporous silica catalyst prepared by the aforementioned method is characterized in that it is applied to the removal of sulfonamide antibiotics in an aquatic environment.

[0018] Furthermore, the specific steps for applying the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst to the degradation of sulfonamide antibiotics are as follows: the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst is added to the sulfonamide antibiotic solution, and then persulfate is added to start the degradation reaction; after the reaction is completed, the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst material is separated by an external magnetic field, and after being washed and dried with water, it can be reused.

[0019] Furthermore, the persulfate is any one of potassium persulfate, sodium persulfate, potassium peroxymonosulfate, and sodium peroxymonosulfate, or any two mixed in a proportion greater than 0%, or any three mixed in a proportion greater than 0%, or four mixed in a proportion greater than 0%.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The "grinding-calcination" method provided by this invention for synthesizing carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalysts simplifies the operation steps, avoids the generation of waste liquid during the loading of carbon, nitrogen, sulfur, and cobalt ferrite, and shortens the synthesis cycle.

[0022] 2. This invention uses a "grinding-calcination" method to synthesize carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silicon catalysts. It can successfully load sulfur-containing amino acids and cobalt ferrite onto mesoporous silicon materials, and effectively overcome the disadvantage of cobalt ferrite being prone to agglomeration and deactivation. It achieves the advantage of multi-element synergistic acceleration of electron transfer by carbon, nitrogen, sulfur, and cobalt ferrite, and effectively improves the activation efficiency of persulfate.

[0023] 3. The carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst prepared in this invention has high degradation efficiency, short degradation time, low catalyst and persulfate dosage, and wide pH range in the application of efficient activation of persulfate to remove sulfonamide antibiotics.

[0024] 4. The carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst prepared by this invention can be recovered by applying an external magnetic field. It can be recycled after simple rinsing and drying, and still has good efficiency in activating persulfate degradation of sulfonamide antibiotics when continuously recycled. Attached Figure Description

[0025] Figure 1 X-ray diffraction patterns of the carbon, nitrogen, and sulfur doped cobalt ferrite-modified mesoporous silica catalyst prepared in Example 1 of the present invention and the mesoporous silica and cobalt ferrite prepared in Comparative Example 1.

[0026] Figure 2 Raman spectra of the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst prepared in Example 1 of the present invention and the carbon, nitrogen, and sulfur material prepared in Comparative Example 1.

[0027] Figure 3 Field emission scanning electron microscope (FESEM) images of the carbon, nitrogen, and sulfur doped cobalt ferrite-modified mesoporous silicon catalyst prepared in Example 1 of the present invention and the mesoporous silicon prepared in Comparative Example 1.

[0028] Figure 4 The energy dispersive spectrum of the carbon, nitrogen, sulfur doped cobalt ferrite modified mesoporous silica catalyst prepared in Example 1 of the present invention is shown.

[0029] Figure 5 High-resolution transmission electron microscopy (TEM) images of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silicon catalyst prepared in Example 1 of the present invention and the mesoporous silicon, cobalt ferrite, and carbon, nitrogen, and sulfur materials prepared in Comparative Example 1.

[0030] Figure 6 The hysteresis regression curve of the carbon, nitrogen, sulfur doped cobalt ferrite modified mesoporous silicon catalyst prepared in Example 1 of the present invention.

[0031] Figure 7 The graphs show the efficiency of the carbon, nitrogen, and sulfur doped cobalt ferrite-modified mesoporous silica catalyst prepared in Example 1 of the present invention and the mesoporous silica, cobalt ferrite, carbon, nitrogen, and sulfur, cobalt ferrite-mesoporous silica, carbon, nitrogen, and sulfur-mesoporous silica and carbon, nitrogen, and sulfur-cobalt ferrite catalysts prepared in Comparative Example 1 for removing sulfamethoxazole.

[0032] Figure 8 The graphs show the removal efficiency of sulfamethoxazole by the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst prepared in Example 1 of the present invention and the carbon doped cobalt ferrite modified mesoporous silica catalyst prepared in Comparative Example 2.

[0033] Figure 9 The graph shows the efficiency of the carbon, nitrogen, and sulfur doped cobalt ferrite-modified mesoporous silica catalyst prepared in Example 1 of this invention in activating potassium persulfate to degrade sulfamethoxazole under different dosages.

[0034] Figure 10 The graph shows the efficiency of the carbon, nitrogen, and sulfur doped cobalt ferrite-modified mesoporous silica catalyst prepared in Example 1 of the present invention in activating potassium persulfate of different concentrations to degrade sulfamethoxazole.

[0035] Figure 11 The graph shows the efficiency of the carbon, nitrogen, and sulfur doped cobalt ferrite-modified mesoporous silica catalyst prepared in Example 1 of the present invention in activating potassium persulfate to degrade sulfamethoxazole at different pH values.

[0036] Figure 12 The cyclic regeneration efficiency diagram of the carbon, nitrogen, sulfur doped cobalt ferrite modified mesoporous silica catalyst prepared in Example 1 of the present invention for the degradation of sulfamethoxazole by potassium persulfate.

[0037] Figure 13The graph shows the efficiency of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst prepared in Example 1 of the present invention in activating potassium persulfate to degrade sulfamethoxazole in different actual water bodies. Detailed Implementation

[0038] The following detailed description, in conjunction with the accompanying drawings, provides some embodiments of the present invention, clearly and completely illustrating the technical solutions in these embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the present invention are within the scope of protection of the present invention.

[0039] This invention provides a method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst, comprising the following steps:

[0040] 1): Add alkyl quaternary ammonium salt, anhydrous ethanol, ammonium hydroxide and inorganic silicon source to water, stir evenly and let stand for the required process time;

[0041] The addition of these components triggers a chemical reaction. Under the alkaline conditions created by ammonium hydroxide, the inorganic silicon source undergoes hydrolysis and cross-linking around the template agent alkyl quaternary ammonium salt, thereby forming a mesoporous silicon material containing the template agent with a hexagonal liquid crystal phase structure. The addition of anhydrous ethanol can alter the hydrolysis and cross-linking rate of the silicon source, causing the mesoporous silicon molecular sieve material to form spherical particles.

[0042] 2): Separate the white solid obtained by natural precipitation after standing, remove the alkyl quaternary ammonium salts remaining inside the white solid particles, wash and dry to obtain mesoporous silicon material;

[0043] The aforementioned components undergo a chemical reaction, producing a white precipitate, which, upon separation, yields a white solid. The alkyl quaternary ammonium salt acts as a template agent; removing the template agent yields ordered channels.

[0044] 3): Place mesoporous silica material, cobalt ferrite particles, and sulfur-containing amino acids (such as cysteine, methionine, and cysteine) into a mortar and grind for the required time.

[0045] 4): The ground material is calcined in a protective atmosphere to obtain carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst.

[0046] Further, in step 1), the mass ratio of alkyl quaternary ammonium salt to water is 0.325~0.45:50, and the volume ratio of anhydrous ethanol, ammonium hydroxide, inorganic silicon source and water is 20~28:7~9:1.5~2.5:70~90.

[0047] Furthermore, the stirring time in step 1) is 30~150 min, and the natural sedimentation time is 12~20 h.

[0048] Further, in step 2), any one of the following methods can be selected: solvent reflux method, calcination method, and microwave method to remove the alkyl quaternary ammonium salt, thereby obtaining mesoporous silicon material.

[0049] Further, in step 3), the mass ratio of mesoporous silicon material, cobalt ferrite, and sulfur-containing amino acids is 0.5:0.70~0.25:0.25~0.70.

[0050] Furthermore, in step 3), the grinding time in the mortar is 30-90 minutes.

[0051] Further, in step 4), the carbon, nitrogen, and sulfur-doped cobalt ferrite mesoporous silica catalyst is calcined under a nitrogen atmosphere at a temperature of 500~600℃, a heating rate of 2~5℃ / min, and a holding time of 3.5~6.5h.

[0052] The application of the highly efficient activated persulfate-modified cobalt ferrite-modified mesoporous silica catalyst prepared by the above method in the degradation of organic pollutants in water, specifically sulfonamide antibiotics.

[0053] Furthermore, the specific steps for preparing the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst using the above method in the degradation of organic pollutants such as sulfonamide antibiotics in water are as follows: the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica of the present invention is added to the sulfonamide antibiotic solution as a catalyst, and then persulfate is added to start the degradation reaction. After the reaction is completed, the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst is separated by an external magnetic field, and can be reused after cleaning and drying.

[0054] Furthermore, the persulfate is any one of potassium persulfate, sodium persulfate, potassium peroxymonosulfate, or sodium peroxymonosulfate, or any two mixed in a proportion greater than 0%, or any three mixed in a proportion greater than 0%, or four mixed in a proportion greater than 0%.

[0055] Example 1

[0056] This embodiment provides a method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silicon catalyst, the steps of which are as follows:

[0057] (1) Add 3.0g of alkyl quaternary ammonium salt, 125mL of anhydrous ethanol, 40mL of ammonium hydroxide and 10mL of tetraethyl orthosilicate to 400mL of water and stir for 30min, then allow to precipitate naturally for 12h.

[0058] (2) Separate the naturally precipitated white solid, weigh the dried white solid into a tube furnace, calcine it at 550°C for 5 hours in an air atmosphere, wash the calcined material, and dry it at 60°C to obtain mesoporous silicon material.

[0059] (3) Add 1.0g of mesoporous silica, 0.56g of cobalt ferrite particles and 1.12g of cysteine ​​to a mortar and grind thoroughly for 30min.

[0060] (4) Place the ground mixture in a tube furnace, and under nitrogen atmosphere protection, heat at a rate of 2℃ / min and calcine at 550℃ for 5h. After removing the material, carbon, nitrogen and sulfur doped cobalt ferrite modified mesoporous silicon catalyst (C / N / S / CFO / Si) can be obtained.

[0061] Comparative Example 1

[0062] Mesoporous silica is the mesoporous silica material obtained in step (2) of Example 1. Cobalt ferrite (CFO) is a commercial reagent and is used directly. The carbon-nitrogen-sulfur material is prepared by grinding cysteine ​​and calcining it under the same conditions as step (4) of Example 1. The preparation method of cobalt ferrite-mesoporous silica material differs from that of Example 1 in that step (3) involves grinding 1.0 g of mesoporous silica and 0.56 g of cobalt ferrite particles thoroughly for 30 min, while the other steps are the same as in Example 1. The preparation method of carbon-nitrogen-sulfur-mesoporous silica material differs from that of Example 1 in that step (3) involves grinding 1.0 g of mesoporous silica and 1.12 g of cysteine ​​thoroughly for 30 min, while the other steps are the same as in Example 1. The preparation method of carbon-nitrogen-sulfur-cobalt ferrite material differs from that of Example 1 in that step (3) involves grinding 0.56 g of cobalt ferrite particles and 1.12 g of cysteine ​​thoroughly for 30 min, while the other steps are the same as in Example 1.

[0063] Figure 1 The images show the X-ray diffraction patterns of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst in Example 1 and the mesoporous silica, cobalt ferrite, and carbon, nitrogen, and sulfur materials in Comparative Example 1. Figure 1 It can be seen that the diffraction peaks of mesoporous silicon appear around 2θ = 20-25°, while the diffraction peaks of cobalt ferrite appear around 2θ = 18.6°, 30.0°, 35.2°, 43.1°, 53.3°, 57.2°, and 62.7° (PDF#22-1086), which correspond to the (111), (220), (311), (400), (422), (511), and (440) crystal planes of cobalt ferrite, respectively. The X-ray diffraction pattern of the carbon, nitrogen, and sulfur doped cobalt ferrite-modified mesoporous silicon catalyst shows the same characteristic peaks as those of mesoporous silicon and cobalt ferrite, and the peak angles remain unchanged, indicating that cobalt ferrite was successfully loaded onto mesoporous silicon.

[0064] Figure 2 The images show the Raman spectra of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst in Example 1 and the carbon, nitrogen, and sulfur material in Comparative Example 1. The image is located at 1369 cm⁻¹. -1 The D peak at 1580 cm⁻¹ represents incomplete carbon atoms with many structural defects. -1 The G peak at point I represents the degree of graphitization of the material.D / I G The value is used to represent the disorder and defect structure of carbon materials. A larger value indicates a higher degree of disorder and a greater number of defect structures in the carbon material. Figure 2 It can be seen that the carbon, nitrogen, and sulfur doped cobalt ferrite-modified mesoporous silica catalyst has I D / I G The value is greater than that of carbon, nitrogen, and sulfur materials. D / I G Value, I D / I G An increase in the value indicates the formation of more defective structures in the carbon atom crystal, which is conducive to the formation of more catalytic active sites, promotes the activation of persulfate, and thus achieves the removal of sulfonamide antibiotics.

[0065] Figure 3 These are field emission scanning electron microscope (FESEM) images of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst from Example 1 and the mesoporous silica, cobalt ferrite, and carbon, nitrogen, and sulfur materials from Comparative Example 1. Figure 3 It can be seen that mesoporous silica exhibits a dispersed and uniform spherical morphology; cobalt ferrite has a rough surface and severe agglomeration; carbon, nitrogen, and sulfur materials exhibit a blocky morphology with fewer surface defects. The carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst successfully preserved the spherical morphology characteristics of the mesoporous silica material. Figure 4 The energy dispersive spectrum of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst in Example 1 is shown below. Figure 4 It can be seen that iron, cobalt, oxygen, carbon, nitrogen, sulfur and silicon elements were detected on the carbon, nitrogen and sulfur doped cobalt ferrite modified mesoporous silicon catalyst in Example 1, proving that cobalt ferrite and carbon, nitrogen and sulfur were successfully loaded on mesoporous silicon.

[0066] Figure 5 These are high-resolution transmission electron microscopy (TEM) images of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst from Example 1 and the mesoporous silica from Comparative Example 1. Figure 5 As can be seen from this, mesoporous silicon has an ordered pore structure; Figure 5 b and Figure 5 The gray circles on the top (c) represent mesoporous silicon materials, and the black particles represent cobalt ferrite particles. Figure 5 The gray bands on d represent carbon layers. (By...) Figure 5 As can be seen from b, c, and d, the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst retains the ordered channels of the mesoporous silica material, uniformly disperses the cobalt ferrite particles, and generates a carbon layer.

[0067] Figure 6 The image shows the hysteresis regression curve of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst in Example 1. Figure 6 It is known that the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst is magnetic and has a saturation magnetization (Ms) of 10.98 emu / g, which is beneficial for the rapid separation of the material from the aqueous solution after the degradation experiment.

[0068] Sulfamethoxazole is a representative sulfonamide antibiotic, widely detected in water bodies. Therefore, sulfamethoxazole was selected as a representative to test the degradation performance of the catalyst prepared in this invention on sulfonamide antibiotics. 5 mg of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst from Example 1, and the mesoporous silica, cobalt ferrite, carbon, nitrogen, and sulfur, cobalt ferrite-mesoporous silica, carbon, nitrogen, and sulfur-mesoporous silica, and carbon, nitrogen, and sulfur-cobalt ferrite catalysts from Comparative Example 1 were added to 100 mL of sulfamethoxazole solution, with an initial concentration of 10 mg / L. 0.15 mmol / L potassium persulfate (PMS) was added to initiate the degradation reaction. The initial pH of the solution was 7. After the reaction was completed, the concentration of remaining sulfonamide antibiotics in the solution was measured.

[0069] like Figure 7 It can be seen that the adsorption rates of sulfamethoxazole for 10 min by mesoporous silica, cobalt ferrite, carbon, nitrogen, and sulfur, cobalt ferrite-mesoporous silica, carbon, nitrogen, and sulfur-cobalt ferrite, and carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalysts are all <10%, indicating that the above materials have weak adsorption capacity for sulfamethoxazole at this dosage. The removal rate of sulfamethoxazole by PMS alone is 11.29% in 10 min. The removal rates of sulfamethoxazole by PMS activated with mesoporous silica, cobalt ferrite, carbon, nitrogen, and sulfur, cobalt ferrite-mesoporous silica, carbon, nitrogen, and sulfur-cobalt ferrite are 10.73%, 25.47%, 20.58%, 38.72%, 20.01%, and 44.62%, respectively. However, the removal rate of sulfamethoxazole by carbon, nitrogen, sulfur doped cobalt ferrite-modified mesoporous silica activated PMS can reach 96.63%, which indicates that simultaneously loading carbon, nitrogen, sulfur and cobalt ferrite onto mesoporous silica materials can significantly improve the degradation performance of sulfamethoxazole.

[0070] Comparative Example 2

[0071] This embodiment provides an application of a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silicon catalyst, the steps of which are as follows:

[0072] By replacing cysteine ​​with sucrose in step (3) of Example 1, while keeping the other steps and conditions unchanged, a carbon-doped cobalt ferrite-modified mesoporous silicon catalyst (C / CFO / Si) can be obtained. Alternatively, by replacing cysteine ​​with L-histidine in step (3) of Example 1, while keeping the other steps and conditions unchanged, a carbon-nitrogen-doped cobalt ferrite-modified mesoporous silicon catalyst (C / N / CFO / Si) can be obtained.

[0073] Five mg of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst from Example 1 and five mg of the carbon-doped cobalt ferrite-modified mesoporous silica material and carbon and nitrogen-doped cobalt ferrite-modified mesoporous silica material from Comparative Example 2 were dispersed in 100 mL of sulfamethoxazole solution. The initial concentration of sulfamethoxazole was 10 mg / L. 0.15 mmol / L PMS was added to initiate the degradation reaction. The initial pH of the solution was 7. After the reaction was complete, the concentration of the remaining sulfonamide antibiotics in the solution was determined using high-performance liquid chromatography (HPLC).

[0074] like Figure 8 It was found that the adsorption rates of sulfamethoxazole by carbon-doped cobalt ferrite-modified mesoporous silica catalysts, carbon-nitrogen-doped cobalt ferrite-modified mesoporous silica catalysts, and carbon-nitrogen-sulfur-doped cobalt ferrite-modified mesoporous silica catalysts were all less than 10%. The removal rate of sulfamethoxazole by PMS after 10 min was 11.29%. The removal rates of sulfamethoxazole by PMS activated by carbon-doped cobalt ferrite-modified mesoporous silica catalysts, carbon-nitrogen-doped cobalt ferrite-modified mesoporous silica catalysts, and carbon-nitrogen-sulfur-doped cobalt ferrite-modified mesoporous silica catalysts were 50.24%, 56.37%, and 96.63%, respectively. This indicates that simultaneous carbon-nitrogen-sulfur doping significantly improves the efficiency of PMS activation in degrading sulfamethoxazole compared to carbon doping alone.

[0075] Example 2

[0076] This embodiment provides an application of a carbon, nitrogen, and sulfur-doped cobalt ferrite mesoporous silicon catalyst, the steps of which are as follows:

[0077] 3 mg, 5 mg, 10 mg, and 20 mg of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst obtained in Example 1 were dispersed in 100 mL of different sulfamethoxazole solutions, with an initial sulfamethoxazole concentration of 10 mg / L. The degradation reaction was initiated by adding 0.15 mmol / L PMS. The initial pH of the solution was 7. After the reaction was completed, the concentration of the remaining sulfonamide antibiotics in the solution was determined using high-performance liquid chromatography (HPLC).

[0078] like Figure 9 It can be seen that the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst can complete the degradation of sulfamethoxazole in 10 minutes under different dosages (3 mg, 5 mg, 10 mg and 20 mg), with removal rates of 90.38%, 96.39%, 96.71% and 97.95%, respectively. This indicates that the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst can efficiently activate PMS to degrade sulfamethoxazole even at low dosages.

[0079] Example 3

[0080] This embodiment provides an application of a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silicon catalyst, the steps of which are as follows:

[0081] Five mg of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst obtained in Example 1 was dispersed in 100 mL of sulfamethoxazole solution, with an initial concentration of 10 mg / L. The degradation reaction was then initiated by adding 0.10 mmol / L, 0.15 mmol / L, 0.20 mmol / L, and 0.30 mmol / L of PMS, respectively. The initial pH of the solution was 7. After the reaction was completed, the concentration of the remaining sulfonamide antibiotics in the solution was measured.

[0082] like Figure 10 It can be seen that the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst can complete the degradation of sulfamethoxazole in 10 min at different PMS concentrations (0.10 mmol / L, 0.15 mmol / L, 0.20 mmol / L and 0.30 mmol / L), with removal rates of 90.04%, 96.39%, 95.71% and 96.61%, respectively. This indicates that the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst can efficiently activate PMS to degrade sulfamethoxazole even at low PMS concentrations.

[0083] Example 5

[0084] This embodiment provides an application of a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silicon catalyst, the steps of which are as follows:

[0085] Five mg of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst obtained in Example 1 was dispersed in 100 mL of sulfamethoxazole solution. The initial concentration of sulfamethoxazole was 10 mg / L. Then, 0.15 mmol / L of PMS was added to initiate the degradation reaction. The pH values ​​of the reaction system were 5, 7, and 9, respectively. After the reaction was completed, the concentration of the remaining sulfonamide antibiotics in the solution was measured.

[0086] like Figure 11 It can be seen that when the pH of the sulfamethoxazole solution is 5, 7, and 9, the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst can complete the degradation reaction in 10 min, with removal rates of 94.25%, 96.40%, and 94.14%, respectively. This indicates that the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalyst can activate PMS and effectively remove sulfamethoxazole within a wide pH range.

[0087] Example 4

[0088] This embodiment provides an application of a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silicon catalyst, the steps of which are as follows:

[0089] Five mg of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst obtained in Example 1 was dispersed in 100 mL of sulfamethoxazole solution. The initial concentration of sulfamethoxazole was 10 mg / L. Then, 0.15 mmol / L of PMS was added to initiate the degradation reaction. The initial pH of the solution was 7. After the reaction was completed, the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst was separated using an external magnetic field. After washing with water and drying, it could be reused.

[0090] like Figure 12 As shown, after three cycles of regeneration, the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst still achieved a 79.59% removal rate of sulfamethoxazole in activated PMS, indicating that the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst has good regeneration and reuse properties.

[0091] Example 5

[0092] This embodiment provides an application of a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silicon catalyst, the steps of which are as follows:

[0093] Five mg of the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst obtained in Example 1 was added to 100 mL of sulfamethoxazole solution in actual water bodies (tap water, lake water, and secondary effluent from a wastewater treatment plant). The initial concentration of sulfamethoxazole was 10 mg / L. Then, 0.15 mmol / L of PMS was added to each solution to initiate the degradation reaction. After the reaction was completed, the concentration of the remaining sulfonamide antibiotics in the solution was measured.

[0094] like Figure 13 It can be seen that the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst activated by PMS can also remove sulfamethoxazole from actual water bodies (tap water, lake water, and secondary effluent from sewage treatment plants) within 10 minutes, with a removal rate of over 89.24%. This indicates that the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst has high efficiency in removing sulfamethoxazole from actual water bodies.

[0095] Examples 6-11

[0096] The preparation methods of the catalysts in Examples 6-11 are the same as those in Example 1, with the main difference being some parameters, as shown in the table below:

[0097]

[0098] Examples 8-13 prepared carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalysts. The tests showed that the removal effect of activated PMS on the degradation of sulfamethoxazole was comparable to that of the carbon, nitrogen, and sulfur doped cobalt ferrite modified mesoporous silica catalysts prepared in Example 1.

[0099] The above descriptions are merely several embodiments and comparative examples of the present invention and should not be construed as limiting the scope of the present invention in any way. Any modifications or alterations made by those skilled in the art to all or part of the processes described above in the embodiments and comparative examples without departing from the scope of the present invention are equivalent to equivalent implementation cases and comparative cases and are all within the protection scope of the present invention.

Claims

1. A method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst, characterized in that, Includes the following steps: 1): Add alkyl quaternary ammonium salt, anhydrous ethanol, ammonium hydroxide and inorganic silicon source to water, stir evenly and let stand; 2): Separate the white solid obtained by natural precipitation after standing, remove the alkyl quaternary ammonium salt, and obtain mesoporous silicon material after washing and drying; 3): Place the mesoporous silica material, cobalt ferrite particles, and sulfur-containing amino acids into a mortar and grind them for the required time. 4): The ground material is calcined in a protective atmosphere to obtain carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst.

2. The method for preparing the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst according to claim 1, characterized in that, In step 1), the mass ratio of alkyl quaternary ammonium salt to water is 0.325~0.45:50, and the volume ratio of anhydrous ethanol, ammonium hydroxide, inorganic silicon source and water is 20~28:7~9:1.5~2.5:70~90.

3. The method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst according to claim 1, characterized in that, The stirring time in step 1) is 30 min to 120 min, and the standing time is 12 to 20 h.

4. The method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst according to claim 1, characterized in that, The method for removing alkyl quaternary ammonium salts in step 2) is any one of solvent reflux method, calcination method or microwave method.

5. The method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst according to claim 1, characterized in that, In step 3), the mass ratio of mesoporous silica, cobalt ferrite, and sulfur-containing amino acids is 0.5:0.70~0.25:0.25~0.

70.

6. The method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst according to claim 1, characterized in that, In step 3), the grinding time in the mortar is 30-90 minutes.

7. The method for preparing a carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst according to claim 1, characterized in that, In step 4), calcination is carried out under a nitrogen atmosphere at a temperature of 500-600℃, a heating rate of 2-5℃ / min, and a holding time of 3.5-6.5h.

8. An application of a carbon, nitrogen, sulfur-doped cobalt ferrite-modified mesoporous silica catalyst prepared by the method described in any one of claims 1 to 7, characterized in that, It is used to remove sulfonamide antibiotics from aquatic environments.

9. The application of the carbon, nitrogen, sulfur-doped cobalt ferrite-modified mesoporous silica catalyst prepared by the method described in claim 8, characterized in that, The specific steps for applying the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst to the degradation of sulfonamide antibiotics are as follows: the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst is added to the sulfonamide antibiotic solution, and then persulfate is added to start the degradation reaction; after the reaction is completed, the carbon, nitrogen, and sulfur-doped cobalt ferrite-modified mesoporous silica catalyst material is separated by an external magnetic field and then washed and dried with water.

10. The application of the carbon, nitrogen, sulfur-doped cobalt ferrite-modified mesoporous silica catalyst prepared by the method described in claim 9, characterized in that, The persulfate is any one of potassium persulfate, sodium persulfate, potassium peroxymonosulfate, and sodium peroxymonosulfate, or any two mixed in a proportion greater than 0%, or any three mixed in a proportion greater than 0%, or four mixed in a proportion greater than 0%.

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