Co-Fe c / c composite catalyst and preparation method and application thereof

Abstract

The application discloses a Co-FeC / C composite catalyst, which is a composite of FeC and C, is doped with Co to adjust FeC, and is prepared through a medium-temperature water bath and a high-temperature calcination method; wherein FeC serves as a core catalytic active phase and provides active sites of a Fenton-like reaction; the C carrier serves as a dispersion carrier and prevents FeC particles from agglomerating, and functional groups on the surface of the C carrier can assist in adsorbing organic pollutants; and the electronic structure of FeC is adjusted through Co doping, wherein Co atoms enter the crystal lattice of FeC to form Fe-Co metal bonds, regulate the d-band center position of FeC, and accelerate the redox cycle of Fe 2+ / Fe 3+ . The application further discloses a preparation method and application of the composite catalyst, and solves the problem that the existing Fenton-like catalyst Fe 3+ and Fe 2+ cycle too slowly, resulting in low free radical generation efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of new material catalyst synthesis methods, specifically relating to Co-FeC / C composite catalysts, and also to the preparation methods and applications of the above-mentioned composite catalysts. Background Technology

[0002] The continuous advancement of industrialization has made the emission of various recalcitrant organic pollutants in industrial production increasingly prominent. Tens of thousands of tons of organic pollutants such as antibiotics, dyes, and phenolic compounds are emitted annually. These pollutants have stable structures and are difficult to effectively degrade using traditional treatment technologies. Their long-term accumulation poses a serious and continuous threat to the balance of the ecological environment and human health.

[0003] The Fenton process is a commonly used technology for the treatment of traditional organic pollutants, which utilizes Fe... 2+ The H2O2 system generates hydroxyl radicals to oxidize and decompose pollutants, but this system has many inherent drawbacks: hydrogen peroxide has weak mineralization ability, and its explosive nature leads to high transportation and storage costs. Furthermore, the catalyst within the system is prone to deactivation, easily generating secondary pollution, thus limiting its practical application. To overcome the shortcomings of the Fenton process, persulfate advanced oxidation technology has emerged. This technology generates sulfate radicals with higher redox potentials by activating permonosulfate (PMS) and perdisulfate (PDS). It boasts advantages such as fast reaction rate, wide applicable pH range, mild reaction conditions, and high mineralization rate of organic pollutants, making it a research hotspot in the field of organic wastewater treatment.

[0004] However, existing Fenton-like catalysts adapted to advanced persulfate oxidation technologies still face numerous technical bottlenecks: most catalysts are made of a single metal or metal oxide, failing to simultaneously achieve efficient activation of the oxidant and effective adsorption of pollutants, thus limiting their catalytic performance; while some modified catalysts have improved performance, their preparation processes are complex, raw material costs are high, and catalytic stability is insufficient, making it difficult to meet the large-scale demands of practical industrial applications; simultaneously, existing catalysts also suffer from insufficient activation capacity, unclear structure-activity relationships, and limited catalytic degradation efficiency, with the core challenge being Fe... 3+ with Fe 2+ The redox cycle rate is too slow, resulting in low efficiency in free radical generation, which makes it impossible to achieve rapid and efficient degradation of organic pollutants.

[0005] Therefore, it is necessary to develop a catalyst that is simple to prepare, low in cost, exhibits excellent catalytic performance and good stability, and can effectively accelerate Fe... 3+ with Fe 2+ Recycled Fenton-like catalysts are of vital practical significance and application value for improving the efficiency of organic pollutant treatment and promoting the industrial application of persulfate advanced oxidation technology. Summary of the Invention

[0006] The first objective of this invention is to provide a Co-FeC / C composite catalyst. This addresses the limitations of existing Fenton-like catalysts for Fe... 3+ with Fe 2+ The cycle is too slow, resulting in low efficiency in free radical generation.

[0007] A second objective of this invention is to provide a method for preparing the aforementioned composite catalyst.

[0008] A third objective of this invention is to provide applications of the aforementioned composite catalyst.

[0009] The first technical solution adopted in this invention is: a Co-FeC / C composite catalyst, which is a composite of FeC and C, and FeC is modulated by Co doping, and is prepared by medium-temperature water bath and high-temperature calcination.

[0010] The first technical solution adopted in this invention is further characterized by: FeC serves as the core catalytic active phase, providing active sites for Fenton-like reactions. The C support acts as a dispersion carrier, preventing FeC particle aggregation, while the functional groups on the C support surface can assist in the adsorption of organic pollutants. Furthermore, Co doping modulates the electronic structure of FeC, allowing Co atoms to enter the FeC lattice and form Fe-Co metallic bonds, thus regulating the d-band center position of FeC and accelerating the Fe... 2+ / Fe 3+ The redox cycle.

[0011] The second technical solution adopted in this invention is: a method for preparing Co-FeC / C composite catalysts, the preparation steps of which are as follows: Step 1: Prepare organic precursors using a medium-temperature water bath method: Dissolve and heat the carbon source and carbon source regulator to construct an organic precursor containing amino and hydroxyl functional groups; Step 2: Preparation of Co-FeC / C catalyst precursor by complexation method: The metal salt solution is mixed with the organic precursor to carry out a complexation reaction. After the reaction, the solution is continuously heated and dried to obtain the catalyst precursor. Step 3: The Co-FeC / C catalyst was prepared by high-temperature calcination after grinding the catalyst precursor.

[0012] The second technical solution adopted in this invention is further characterized by: Step 1 is as follows: Weigh the carbon source and carbon source regulator at a mass ratio of 0.1~1:0.01~0.2, completely dissolve them in deionized water and heat to 35℃~45℃, stir for 10~30min to obtain solution A, which is the organic precursor solution.

[0013] In step 1, the carbon source is any one or more of dicyandiamine, melamine, and urea; the carbon source regulator is any one or more of glucose, oxalic acid, glycerol, and ethylene glycol, which adjusts the content of amino and hydroxyl functional groups in the carbon material, thereby regulating its complexation with Co and Fe.

[0014] Step 2 is as follows: Under water bath conditions of 35℃~45℃, two or more metal salt solutions of equal volume are mixed evenly and slowly added dropwise to solution A to carry out a complexation reaction to obtain solution B; solution B is further heated to 75℃~85℃ and filtered, and then the filtrate is stirred at this water bath temperature until the water evaporates, and then dried at 60-70℃ for 10~14h to obtain the catalyst precursor.

[0015] In step 2, the metal salt solution is any one or more of the chloride, sulfate, nitrate or organic complex solutions of Co and Fe, wherein Co is a divalent precursor and Fe is a trivalent precursor, used to coordinate and complex with the amino and hydroxyl groups in the carbon source, respectively; the drying method is one of vacuum drying, conventional drying or freeze drying.

[0016] Step 3 is as follows: Grind the dried catalyst precursor in a mortar for 15-20 minutes, then calcine it at a high temperature of 800-1000℃ with a temperature increase of 5℃ / min, and keep it at that temperature for 1-5 hours to obtain the Co-FeC / C catalyst.

[0017] The atmosphere during the high-temperature roasting in step 3 is any one or a mixture of several of the following gases: air, nitrogen, hydrogen, and carbon monoxide.

[0018] The third technical solution adopted in this invention is the application of Co-FeC / C catalyst in Fenton-like reactions.

[0019] The third technical solution adopted in this invention is further characterized by: An organic pollutant solution with a concentration of 5 mg / L to 30 mg / L was used as the raw material solution, with water as the solvent. A catalyst and an oxidant were added, and the mass-to-volume ratio of the organic pollutant solution, catalyst, and oxidant was 10:1 to 4:0.5 to 8. The reaction was carried out at room temperature in the dark. The organic pollutant was any one of antibiotics, dyes, or phenolic compounds, and the oxidant was any one of hydrogen peroxide, persulfate PMS, or perdisulfate PDS.

[0020] The beneficial effects of this invention are: 1. Advantages of the preparation principle: This invention relies on the theory of hard and soft acids and bases to achieve precise coordination between metals and carbon sources. Based on the principle of "hard attracts hard, soft attracts soft," Fe... 3+ (Hard acid) coordinates with the hydroxyl group (hard base) in the carbon source, Co 2+The soft acid coordinates with the amino group (cross-linked base) in the carbon source to achieve uniform dispersion of Fe and Co in the precursor, avoiding the aggregation of metal ions. This results in the formation of uniform Co-FeC active sites after calcination, which improves the stability of the catalyst's catalytic performance.

[0021] 2. Advantages of Co-doping modulation: The Co-FeC / C composite catalyst of this invention precisely modulates the electronic structure of FeC through Co doping. Co atoms enter the FeC lattice to form Fe-Co metallic bonds, shifting the d-band center of FeC towards the Fermi level, reducing the electron cloud density of Fe, thereby optimizing the redox potential of Fe and accelerating the oxidation-reduction reaction of Fe. 2+ / Fe 3+ The increased cycle rate improved the efficiency of free radical generation, solving the problem of traditional Fenton-like catalysts for Fe... 2+ / Fe 3+ The problem is that the loop is too slow.

[0022] 3. Advantages of the catalyst structure: This invention adopts a composite structure of FeC and C. FeC serves as the core catalytic active phase, possessing excellent Fenton-like catalytic activity. It can act as an active site for activating persulfate or hydrogen peroxide, rapidly breaking the O2O bonds of the oxidant to generate strong oxidizing free radicals. The C support has a high specific surface area and abundant pore structure, which can effectively disperse FeC particles and prevent their aggregation. At the same time, the functional groups on the surface of the C support can assist in the adsorption of organic pollutants, enhancing the catalyst's ability to enrich pollutants, thereby further improving the catalytic degradation efficiency.

[0023] 4. Advantages of the preparation process: The preparation process of this invention is simple and low in cost. It adopts a two-step method of medium-temperature water bath and high-temperature calcination, which does not require complicated equipment and expensive raw materials. At the same time, the catalyst has excellent catalytic performance and stability and can be reused many times, which reduces the cost of organic pollutant treatment.

[0024] 5. Broad Spectrum Applicability Advantage: The catalyst of this invention has broad spectrum applicability and can efficiently activate various oxidants such as persulfate (PMS), perdisulfate (PDS), and hydrogen peroxide (H2O2). It has excellent degradation effects on various organic pollutants such as phenols, antibiotics, and dyes, and can be effectively applied to the treatment of industrial organic wastewater to reduce environmental pollution. Attached Figure Description

[0025] Figure 1 The XRD characterization pattern of the Co-FeC / C catalyst of this invention is shown below. Figure 2 The degradation efficiency of Co-FeC / C composite catalysts with different ratios of Co and Fe prepared in Example 1 of this invention is shown in the figure after 90 min at room temperature in the dark. Figure 3The degradation efficiency of Co-FeC / C composite catalysts with different carbon sources prepared in Example 2 of this invention is shown in the figure after 90 min at room temperature in the dark. Figure 4 The degradation efficiency of Co-FeC / C composite catalysts prepared at different calcination temperatures in Example 3 of this invention was measured at room temperature in the dark for 90 minutes. Figure 5 The effect of different oxidants on the degradation performance of the Co-FeC / C composite catalyst prepared in Example 4 of this invention is shown in the degradation efficiency graph after 90 min at room temperature in the dark. Figure 6 The effect of different catalyst addition amounts on degradation performance in Example 5 of this invention is shown in the degradation efficiency graph after 90 min at room temperature in the dark. Figure 7 To demonstrate the universality of the Co-FeC / C composite catalyst prepared in Example 6 of this invention for the degradation of different organic pollutants, the degradation efficiency is shown in the graph after 90 min at room temperature in the dark. Figure 8 The stability of the Co-FeC / C composite catalyst prepared in Example 7 of this invention is shown in the degradation efficiency diagram at room temperature in the dark for 90 minutes. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] This invention provides a Co-FeC / C composite catalyst, which is a complex of FeC and C, and modulates the electronic structure of FeC by Co doping: 1. Component Roles: FeC serves as the core catalytic active phase, providing active sites for Fenton-like reactions and directly activating persulfate or hydrogen peroxide to generate strong oxidizing free radicals; C acts as the dispersion support, its high specific surface area and porous structure preventing FeC particle agglomeration and improving catalyst stability. Simultaneously, its surface functional groups assist in the adsorption of organic pollutants, enhancing the catalyst's ability to enrich pollutants; Co atoms enter the FeC lattice to form Fe-Co metallic bonds, optimizing the electronic structure of FeC and accelerating Fe... 2+ / Fe 3+ The redox cycle enhances catalytic activity.

[0028] 2. Preparation principle: This catalyst relies on the hard and soft acid-base theory to achieve precise coordination between the metal and the carbon source. Fe is a trivalent metal precursor (hard acid) that coordinates with the hydroxyl group (hard base) in the carbon source, while Co is a divalent metal precursor (soft acid) that coordinates with the amino group (borderline base) in the carbon source. It is prepared by medium-temperature water bath and high-temperature calcination, which achieves uniform distribution of active sites and improves the catalytic performance of the catalyst in Fenton-like reactions.

[0029] This invention also provides a method for preparing a Co-FeC / C composite catalyst, specifically according to the following steps: Step 1: Prepare the organic precursor using a medium-temperature water bath method. Weigh 0.5g~5g of carbon source and 0.05g~1g of carbon source regulator, dissolve them in 40mL of deionized water, and heat to 35℃~45℃. Stir for 10~30min to obtain solution A, which is the organic precursor solution.

[0030] In step 1, the carbon source is one or more of dicyandiamine, melamine, and urea. During heating, it hydrolyzes to produce a large number of amino functional groups, which are Co. 2+ Provides coordination; the carbon source regulator is one or more of glucose, oxalic acid, glycerol, and ethylene glycol, whose molecular structure contains a large number of hydroxyl functional groups and is Fe 3+ It provides coordination, which can adjust the content of hydroxyl functional groups in carbon materials, and at the same time synergistically regulates the functional group ratio of organic precursors with carbon sources, thereby precisely matching Co. 2+ and Fe 3+ The coordination requirements are met, which improves the accuracy of subsequent complexation reactions.

[0031] Step 2: Prepare the Co-FeC / C catalyst precursor using a complexation method; under water bath conditions of 35℃~45℃, mix equal volumes of metal salt solutions evenly and slowly add them dropwise to solution A to carry out a complexation reaction. According to the hard and soft acid-base theory, Fe... 3+ (Hard acids) preferentially coordinate with the hydroxyl groups (hard bases) in the carbon source, Co 2+ The (soft acid) preferentially coordinates with the amino group (cross-base) in the carbon source to form a stable metal-organic coordination structure, resulting in solution B. Solution B is then heated to 75℃~85℃ and filtered. The filtrate is then stirred at this water bath temperature until the water evaporates, and then dried at 60℃ for 10~14h.

[0032] In step 2, the metal salt solution is one or more of the chloride, sulfate, nitrate, or organic complex solutions of transition metals Co and Fe, wherein Co is a divalent precursor (soft acid) and Fe is a trivalent precursor (hard acid), used to coordinate and complex with the amino and hydroxyl groups in the carbon source, respectively; the drying method is one of vacuum drying, conventional drying, or freeze drying.

[0033] Step 3: Prepare Co-FeC / C catalyst by high-temperature calcination. Grind the dried Co-FeC / C catalyst precursor in a mortar for 15-20 min, then transfer it to a tube furnace. Under a special atmosphere, heat the furnace at 5℃ / min to 800℃-1000℃ and hold for 1-5 h to obtain the Co-FeC / C composite catalyst.

[0034] The special atmosphere in step 3 is one or a mixture of air, nitrogen, hydrogen, and carbon monoxide.

[0035] This invention discloses a method for Fenton-like degradation of organic pollutants using a Co-FeC / C composite catalyst. The method employs 50 mL of an organic pollutant solution with a concentration of 5 mg / L to 30 mg / L as the raw material, with water as the solvent. The catalyst dosage is 5 mg to 25 mg, and the oxidant dosage is 2.5 mg to 40 mg. The reaction is carried out at room temperature in the dark, with a stirring rate of 200 rpm to 800 rpm. The organic pollutant is one of an antibiotic, dye, or phenolic compound; the oxidant is one of hydrogen peroxide, persulfate (PMS), or perdisulfate (PDS).

[0036] The prepared Co-FeC / C catalyst was characterized by XRD, and its XRD pattern is shown below. Figure 1 As shown, the characteristic peak at 2θ=44.8° corresponds to the (111) crystal plane of FeC, and the characteristic peak at 2θ=26.5° corresponds to the (002) crystal plane of the C support, proving that the catalyst prepared is a Co-FeC / C composite structure with Co doped on FeC.

[0037] The application of Co-FeC / C catalyst in Fenton-like reaction involved using 50 mL of organic pollutant solution with a concentration of 5 mg / L to 30 mg / L as the raw material, water as the solvent, 5 mg to 25 mg of catalyst, and 2.5 mg to 40 mg of oxidant. The reaction was carried out at room temperature in the dark, with a stirring rate of 200 rpm to 800 rpm.

[0038] The organic pollutant is any one of antibiotics, dyes, or phenolic compounds; the oxidant is any one of hydrogen peroxide, persulfate PMS, or perdisulfate PDS.

[0039] The preparation and performance of the catalyst of the present invention will be further illustrated below through specific embodiments.

[0040] Example 1 This embodiment prepares Co-FeC / C composite catalysts with different ratios of Co and Fe: First, weigh out 0.5g of dicyandiamine and 1g of glucose, 0.5g of dicyandiamine and 0.5g of glucose, 0.5g of dicyandiamine and 0.1g of glucose, 5g of dicyandiamine and 0.1g of glucose, 2g of dicyandiamine and 0.1g of glucose, 1g of dicyandiamine and 0.1g of glucose, 5g of dicyandiamine and 0.05g of glucose, and 2g of dicyandiamine and 0.05g of glucose. Dissolve each of these solutions in 40mL of deionized water and heat to 40℃. Stir for 20min to obtain organic precursor solution A.

[0041] After thoroughly mixing 0.5 ml of 0.01 M ferric nitrate nonahydrate solution and 0.5 ml of 0.01 M cobalt nitrate hexahydrate solution, the mixture was slowly added dropwise to solution A under a 40 °C water bath to carry out a complexation reaction, yielding solution B. Solution B was then heated to 80 °C and filtered. The filtrate was then stirred at this water bath temperature until the water evaporated, and then dried in a vacuum drying oven at 60 °C for 12 h to obtain the catalyst precursor.

[0042] Finally, each precursor was ground in a mortar for 20 min, then transferred to a tube furnace and heated to 900 °C at 5 °C / min under a nitrogen atmosphere, and held for 1 h to obtain Co-FeC / C composite catalysts with different ratios of Co and Fe, which were designated as Co-FeC / C-1:2, Co-FeC / C-1:1, Co-FeC / C-5:1, Co-FeC / C-50:1, Co-FeC / C-20:1, Co-FeC / C-10:1, Co-FeC / C-100:1, and Co-FeC / C-40:1, respectively.

[0043] 5 mg of each of the above catalysts were added to 50 mL of a 20 mg / L tetracycline solution. The mixture was stirred at 600 rpm in the dark at room temperature for 30 min. The absorbance of the tetracycline solution at this time was measured using UV-Vis spectroscopy and recorded as C0, and the time was recorded as t0. 10 mg of potassium peroxymonosulfate was added as an oxidant, and the mixture was stirred continuously in the dark at room temperature. Samples were taken every 15 min for analysis and the absorbance of the solution was recorded as C and the time as t. The degradation efficiency graph was obtained.

[0044] Experimental results are as follows Figure 2 As shown, after 90 min, the Co-FeC / C-20:1 catalyst exhibited the best catalytic degradation performance for tetracycline, with a degradation rate approaching 100%, far exceeding that of catalysts with other ratios. This is because the coordination sites of Co and Fe are more uniformly distributed at this ratio, enabling efficient adsorption and activation of both the oxidant and tetracycline. Relying on the synergistic effect of Co and Fe, active free radicals are rapidly generated, thereby improving the degradation efficiency.

[0045] Example 2 This embodiment prepares Co-FeC / C composite catalysts with different carbon sources: First, 2g of dicyandiamine, melamine, and urea were weighed out as carbon sources, and 0.1g of glucose was added to each as a carbon source regulator. They were dissolved in 40mL of deionized water and heated to 40℃. After stirring for 20min, organic precursor solutions A1, A2, and A3 with three different carbon sources were obtained.

[0046] After thoroughly mixing 0.5 ml of 0.01 M ferric nitrate nonahydrate solution and 0.5 ml of 0.01 M cobalt nitrate hexahydrate solution, the mixture was slowly added dropwise to A1, A2, and A3 respectively under a 40 °C water bath to carry out a complexation reaction, yielding solutions B1, B2, and B3. Each solution was then heated to 80 °C and filtered. Subsequently, each filtrate was stirred at the same water bath temperature until the water evaporated, and then dried in a vacuum drying oven at 60 °C for 12 h to obtain catalyst precursors with different carbon sources.

[0047] Finally, each precursor was ground in a mortar for 20 min, transferred to a tube furnace, and heated to 900℃ at 5℃ / min under a nitrogen atmosphere, and held for 1 h to obtain Co-FeC / C composite catalysts with different carbon sources, which were designated as Co-FeC / C-20:1 (dicyandiamine), Co-FeC / C-20:1 (melamine), and Co-FeC / C-20:1 (urea).

[0048] 5 mg of each of the above catalysts were added to 50 mL of a 20 mg / L tetracycline solution. The mixture was stirred at 600 rpm in the dark at room temperature for 30 min. The absorbance of the tetracycline solution at this time was measured using UV-Vis spectroscopy and recorded as C0, and the time was recorded as t0. 10 mg of potassium peroxymonosulfate was added as an oxidant, and the mixture was stirred continuously in the dark at room temperature. Samples were taken every 15 min for analysis and the absorbance of the solution was recorded as C and the time as t. The degradation efficiency graph was obtained.

[0049] Experimental results are as follows Figure 3 As shown, after 90 min, the degradation rate of the Co-FeC / C-20:1 catalyst with dicyandiamine as the carbon source was close to 100%, which was better than that of the catalysts with melamine and urea as carbon sources. This is because the amino functional group content provided by dicyandiamine is more suitable, which can achieve more complete coordination with the divalent Co precursor. At the same time, it can synergistically regulate the hydroxyl content with the carbon source regulator to match the coordination requirements of the trivalent Fe precursor and optimize the active site structure of the catalyst.

[0050] Example 3 In this embodiment, Co-FeC / C composite catalysts with different calcination temperatures were prepared: First, 2g of dicyandiamine was weighed as the carbon source and 0.1g of glucose was weighed as the carbon source regulator. They were dissolved separately in 40mL of deionized water and heated to 40℃. After stirring for 20min, organic precursor solution A was obtained. 0.5mL of 0.01M ferric nitrate nonahydrate solution and 0.5mL of 0.01M cobalt nitrate hexahydrate solution were mixed evenly and then slowly added dropwise to solution A under a 40℃ water bath to carry out a complexation reaction, resulting in solution B. Solution B was then heated to 80℃ and filtered. The filtrate was then stirred at the same water bath temperature until the water evaporated and then dried in a vacuum drying oven at 60℃ for 12h to obtain the catalyst precursor.

[0051] Then, each precursor was ground in a mortar for 20 min, divided into four portions, and transferred to a tube furnace. Under a nitrogen atmosphere, the temperature was increased to 800℃, 900℃, 950℃, and 1000℃ at a rate of 5℃ / min, respectively, and held for 1 h to obtain Co-FeC / C composite catalysts with different calcination temperatures, which were designated as Co-FeC / C-20:1-800, Co-FeC / C-20:1-900, Co-FeC / C-20:1-950, and Co-FeC / C-20:1-1000, respectively.

[0052] 5 mg of each of the above catalysts were added to 50 mL of a 20 mg / L tetracycline solution. The mixture was stirred at 600 rpm in the dark at room temperature for 30 min. The absorbance of the tetracycline solution at this time was measured using UV-Vis spectroscopy and recorded as C0, and the time was recorded as t0. 10 mg of potassium peroxymonosulfate was added as an oxidant, and the mixture was stirred continuously in the dark at room temperature. Samples were taken every 15 min for analysis and the absorbance of the solution was recorded as C and the time as t. The degradation efficiency graph was obtained.

[0053] Experimental results are as follows Figure 4 As shown, after 90 min, the degradation rate of the Co-FeC / C-20:1-900 catalyst calcined at 900℃ was close to 100%, the degradation rate of the catalyst calcined at 800℃ was 83%, and the degradation rates of the catalysts calcined at 950℃ and 1000℃ were 94% and 81%, respectively. The calcination temperature of 800℃ was insufficient, resulting in incomplete carbonization of the precursor and less exposure of active sites; while excessively high temperatures would lead to metal particle agglomeration, damage to the coordination structure, and reduction of catalytic performance. 900℃ was the optimal calcination temperature.

[0054] Example 4 This example investigates the effect of different oxidants on the degradation performance of Co-FeC / C composite catalysts: The Co-FeC / C-20:1 catalyst prepared in Example 1 was selected as the experimental sample. 5 mg of each catalyst was added to 50 mL of a 20 mg / L tetracycline solution. The mixture was stirred at 600 rpm in the dark at room temperature for 30 min. The absorbance of the tetracycline solution was detected by UV-Vis spectroscopy and recorded as C0, and the time was recorded as t0. 10 mg of hydrogen peroxide, potassium persulfate, and sodium persulfate were added as oxidants, respectively, and recorded as the H2O2 group, PMS group, and PDS group. The mixture was stirred continuously in the dark at room temperature, and samples were taken for analysis every 15 min. The absorbance of the solution was recorded as C and the time as t, and the degradation efficiency graph was obtained.

[0055] Experimental results are as follows Figure 5 As shown, after 90 min, the degradation rate of tetracycline solution in the PMS group was close to 100%, the degradation rate in the PDS group was 95%, and the degradation rate in the H2O2 group was 94%. This indicates that the Co-FeC / C-20:1 composite catalyst has the best activation effect on persulfate, can rapidly generate sulfate free radicals, and achieve efficient degradation of organic pollutants. At the same time, it can also effectively activate hydrogen peroxide and perdisulfate, and has broad-spectrum oxidant compatibility.

[0056] Example 5 This example investigates the effect of different catalyst addition amounts on degradation performance: The Co-FeC / C-20:1 catalyst prepared in Example 1 was selected. 5 mg, 10 mg, 15 mg, 20 mg, and 25 mg of the catalyst were added to 50 mL of a 20 mg / L tetracycline solution. The mixture was stirred at 600 rpm in the dark at room temperature for 30 min. The absorbance of the tetracycline solution was measured using UV-Vis spectroscopy and recorded as C0, with the time recorded as t0. 10 mg of potassium peroxymonosulfate was added as an oxidant, and the mixture was stirred continuously in the dark at room temperature. Samples were taken every 15 min for analysis, and the absorbance of the solution was recorded as C, with the time recorded as t. The degradation efficiency was then obtained.

[0057] Experimental results are as follows Figure 6 As shown, after 90 minutes, the degradation rates of catalysts with addition amounts of 5 mg, 10 mg, 15 mg, 20 mg, and 25 mg were all close to 100%. Considering both catalytic efficiency and economic benefits, 5 mg is the optimal catalyst addition amount for this reaction system. At this point, the number of active sites is sufficient to achieve full activation of the oxidant and efficient degradation of pollutants. Further increasing the catalyst dosage does not significantly improve the effect and will increase costs.

[0058] Example 6 This example explores the universality of the Co-FeC / C composite catalyst in the degradation of different organic pollutants: The Co-FeC / C-20:1 catalyst prepared in Example 1 was selected. 5 mg of each catalyst was added to 50 mL of phenol solution, tetracycline solution, rhodamine B solution, and bisphenol A solution with a concentration of 20 mg / L, respectively. The mixture was stirred at 600 rpm in the dark at room temperature for 30 min. The absorbance of each solution was detected using UV-Vis spectroscopy and recorded as C0, and the time was recorded as t0. 10 mg of potassium peroxymonosulfate was added to each solution as an oxidant. The mixture was stirred continuously in the dark at room temperature, and samples were taken every 15 min for analysis. The absorbance of the solution was recorded as C, and the time was recorded as t. The degradation efficiency graph was obtained.

[0059] Experimental results are as follows Figure 7 As shown, after 90 min, the degradation rate of phenol, tetracycline, rhodamine B, and bisphenol A by the catalyst was close to 100%, indicating that the Co-FeC / C composite catalyst has excellent degradation effect on a variety of organic pollutants such as phenols, antibiotics, and dyes, and has good universality in Fenton-like reactions.

[0060] Example 7 This example investigates the stability of the prepared Co-FeC / C composite catalyst: By changing the stirring time in step 1 (10 min, 20 min, 30 min) and the calcination holding time in step 3 (1 h, 3 h, 5 h), while keeping the other preparation conditions consistent with the Co-FeC / C-20:1 catalyst in Example 1, nine different Co-FeC / C composite catalysts were prepared under different preparation conditions.

[0061] 5 mg of each of the above catalysts were added to 50 mL of a 20 mg / L tetracycline solution. The mixture was stirred at 600 rpm in the dark at room temperature for 30 min. The absorbance of the tetracycline solution at this time was measured using UV-Vis spectroscopy and recorded as C0, and the time was recorded as t0. 10 mg of potassium peroxymonosulfate was added as an oxidant, and the mixture was stirred continuously in the dark at room temperature. Samples were taken every 15 min for analysis and the absorbance of the solution was recorded as C and the time as t. The degradation efficiency graph was obtained.

[0062] Experimental results are as follows Figure 8 As shown, the degradation rate of tetracycline by the catalysts under nine different preparation conditions was all above 94%, with most of them approaching 100%. This indicates that within the parameter range of the Co-FeC / C composite catalyst preparation process of the present invention, small adjustments to the preparation conditions will not significantly affect the performance of the catalyst. The preparation method has good stability and repeatability and is suitable for large-scale preparation.

[0063] The Co-FeC / C composite catalyst of this invention achieves precise modulation of FeC through Co doping, and realizes directional coordination of the functional groups of the metal with the carbon source and carbon source modifier based on the soft and hard acid-base theory. The preparation process is simple and low-cost, and the catalyst has a reasonable distribution, which can efficiently activate oxidants such as persulfate and hydrogen peroxide, rapidly generating strong oxidizing free radicals. When applied to Fenton-like reactions to degrade organic pollutants, it exhibits excellent catalytic performance, broad oxidant compatibility, and strong universality in pollutant degradation. Furthermore, the preparation process has good stability and can be effectively applied to the treatment of industrial organic wastewater, reducing environmental pollution and demonstrating good practical application value.

Claims

1. A Co-FeC / C composite catalyst, characterized in that, The catalyst is a complex of FeC and C, and FeC is modulated by Co doping. It is prepared by medium-temperature water bath and high-temperature calcination. FeC serves as the core catalytic active phase, providing active sites for Fenton-like reactions. The C support acts as a dispersion carrier, preventing FeC particle aggregation, while the functional groups on the C support surface assist in the adsorption of organic pollutants. Furthermore, Co doping modulates the electronic structure of FeC, allowing Co atoms to enter the FeC lattice and form Fe-Co metallic bonds, thus regulating the d-band center position of FeC and accelerating the Fe... 2+ / Fe 3+ The redox cycle.

2. The method for preparing the composite catalyst according to claim 1, characterized in that, The preparation steps are as follows: Step 1: Prepare organic precursors using a medium-temperature water bath method: Dissolve and heat the carbon source and carbon source regulator to construct an organic precursor containing amino and hydroxyl functional groups; Step 2: Preparation of Co-FeC / C catalyst precursor by complexation method: The metal salt solution is mixed with the organic precursor to carry out a complexation reaction. After the reaction, the solution is continuously heated and dried to obtain the catalyst precursor. Step 3: The Co-FeC / C catalyst was prepared by high-temperature calcination after grinding the catalyst precursor.

3. The preparation method according to claim 2, characterized in that, Step 1 is as follows: Weigh the carbon source and carbon source regulator at a mass ratio of 0.1~1:0.01~0.2, completely dissolve them in deionized water and heat to 35℃~45℃, stir for 10~30min to obtain solution A, i.e., organic precursor solution.

4. The preparation method according to claim 3, characterized in that, In step 1, the carbon source is any one or more of dicyandiamine, melamine, and urea; the carbon source regulator is any one or more of glucose, oxalic acid, glycerol, and ethylene glycol, which adjusts the content of amino and hydroxyl functional groups in the carbon material, thereby regulating its complexation with Co and Fe.

5. The preparation method according to claim 4, characterized in that, Step 2 is as follows: Under water bath conditions of 35℃~45℃, two or more metal salt solutions of equal volume are mixed evenly and slowly added dropwise to solution A to carry out a complexation reaction to obtain solution B; solution B is further heated to 75℃~85℃ for filtration, and then the filtrate is stirred at this water bath temperature until the water evaporates, and then dried at 60-70℃ for 10~14h to obtain the catalyst precursor.

6. The preparation method according to claim 5, characterized in that, In step 2, the metal salt solution is any one or more of the chloride, sulfate, nitrate, or organic complex solutions of Co and Fe, wherein Co is a divalent precursor and Fe is a trivalent precursor, used to coordinate and complex with the amino and hydroxyl groups in the carbon source, respectively; the drying method is one of vacuum drying, conventional drying, or freeze drying.

7. The preparation method according to claim 6, characterized in that, Step 3 is as follows: the dried catalyst precursor is ground in a mortar for 15-20 minutes, and then calcined at a high temperature of 800-1000℃ at a rate of 5℃ / min and kept at that temperature for 1-5 hours to obtain the Co-FeC / C catalyst.

8. The preparation method according to claim 7, characterized in that, The atmosphere during the high-temperature roasting in step 3 is any one or a mixture of several of the following gases: air, nitrogen, hydrogen, and carbon monoxide.

9. The application of the Co-FeC / C composite catalyst according to claim 8 in a Fenton-like reaction, characterized in that, An organic pollutant solution with a concentration of 5 mg / L to 30 mg / L was used as the raw material solution, with water as the solvent. A catalyst and an oxidant were added, and the mass-volume ratio of the organic pollutant solution, catalyst, and oxidant was 10:1 to 4:0.5 to 8. The reaction was carried out at room temperature in the dark.

10. The application according to claim 9, characterized in that, The organic pollutant is any one of antibiotics, dyes, or phenolic compounds; the oxidant is any one of hydrogen peroxide, persulfate PMS, or perdisulfate PDS.

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