Preparation of iron and nitrogen doped magnetic wheat straw biochar and its application in degradation of emerging pollutants
By doping iron and nitrogen elements into biochar, a magnetic wheat straw biochar catalyst with abundant active sites and pore structure was prepared, which solved the problems of unsatisfactory catalytic performance and poor recyclability of biochar, and achieved the effect of efficiently removing new pollutants, making it suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- UNIV OF JINAN
- Filing Date
- 2024-07-03
- Publication Date
- 2026-07-31
AI Technical Summary
Existing biochar has unsatisfactory catalytic performance and is difficult to effectively remove new pollutants. Furthermore, biochar has poor recyclability, leading to difficulties in waste disposal.
Iron and nitrogen-doped magnetic wheat straw biochar was prepared by doping it with iron and nitrogen. Combined with hydrothermal treatment and carbonization processes, a catalyst with abundant active sites and pore structure was formed.
It improves the catalytic performance of biochar, simplifies the recycling process, and achieves efficient removal of new pollutants, making it suitable for large-scale industrial production.
Smart Images
Figure CN118751272B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heterogeneous catalysis technology, specifically to the preparation of iron-nitrogen-doped magnetic wheat straw biochar and its application as a catalytic oxidant for removing new pollutants. Background Technology
[0002] Biochar, with its abundant surface functional groups, porous structure, and large specific surface area, has become a research hotspot in carbon-based materials. However, pristine biochar suffers from limited surface functional groups and a small number of active sites, resulting in less than ideal catalytic performance. Studies have shown that incorporating heteroatoms into biochar not only introduces additional functional groups and active sites onto the biochar surface but also integrates these heteroatoms into the carbon matrix through surface functionalization or covalent bonding, further optimizing the electron cloud distribution and improving catalytic performance. Moreover, different heteroatom doping methods or different doping treatments significantly affect the physicochemical properties of the prepared biochar, leading to substantial differences in its catalytic performance.
[0003] Furthermore, the recyclability of biochar is a key concern for practical applications. Therefore, biochar recycling can be achieved by embedding magnetic transition metal particles to provide excellent magnetic response behavior, effectively avoiding cumbersome separation processes. Simultaneously, the doped non-metallic elements possess a certain coordination effect, forming coordination bonds with transition metals to prevent transition metal leakage. This not only avoids the risk of metal ion leaching but also improves the material's stability. Therefore, the co-doping of non-metallic element nitrogen and metallic element iron can not only regulate the electronic structure, functional group types and quantities of biochar but also reduce metal leaching, facilitating catalyst recovery.
[0004] Although there has been some research on iron-nitrogen co-modified carbon-based materials in recent years, the physicochemical properties of carbon-based materials are closely related to factors such as the material preparation method and the properties of the original biomass. Therefore, the development of simple, green, highly stable, high-catalytic-performance, and easily recyclable biochar-based catalysts remains of great significance for waste resource utilization and the treatment of new pollutants. Summary of the Invention
[0005] To address the aforementioned technical problems, the present invention aims to provide a simple method for preparing iron-nitrogen-doped magnetic wheat straw biochar and its application in removing new pollutants, thereby solving the problems of wheat straw waste accumulation and the difficulty in treating new pollutants.
[0006] This invention proposes a method for preparing iron-nitrogen-doped magnetic wheat straw biochar, comprising the following steps:
[0007] (1) Dissolve ferric chloride hexahydrate and urea in ultrapure water at a certain mass ratio. After complete dissolution, add an appropriate amount of 200-mesh wheat straw powder and mix evenly. Pour the solution into a reaction vessel and perform hydrothermal treatment. After hydrothermal treatment, separate and dry the reaction solution to obtain solid powder.
[0008] (2) Under the protection of inert gas, the solid powder obtained in step (1) is carbonized, cooled, washed with ultrapure water and ethanol, dried and ground to obtain iron-nitrogen heteroatom doped magnetic wheat straw biochar.
[0009] Furthermore, in step (1), the hydrothermal conditions are maintained in an oven at 120-180℃ for 8-12 hours.
[0010] Furthermore, the drying temperature after hydrothermal treatment in step (1) is 50-70℃ for 12 hours.
[0011] Furthermore, the carbonization temperature in step (2) is 400-950℃, the carbonization time is maintained at the carbonization temperature for 1.5-3.5 hours, and the heating rate to the carbonization temperature is 5℃ / min. -1 .
[0012] The beneficial effects of adopting the above technical solution are as follows: the raw material for preparing the iron-nitrogen doped wheat straw-based biochar catalyst provided by the present invention is green, economical and readily available, the preparation conditions are mild and the preparation cycle is short, and the prepared biochar has the characteristics of being magnetic, easy to recycle and reuse, and having high economic benefits.
[0013] A magnetic wheat straw biochar catalyst doped with iron and nitrogen was prepared using the method described above.
[0014] The above-mentioned iron-nitrogen-doped magnetic wheat straw biochar catalyst is used in the activation of peracetic acid, degradation of phenol by ferrate, and diclofenac sodium.
[0015] The beneficial effects of this invention are as follows:
[0016] (1) This invention provides a method for preparing iron-nitrogen-doped magnetic wheat straw biochar. Using wheat straw as a matrix, it has the advantages of readily available and economical raw materials, mild preparation conditions, and environmental friendliness compared with existing carbon material preparation technologies. It is also easy to separate from aqueous solutions. It can prevent the environmental harm caused by burning straw and effectively utilize waste wheat straw. It is green and environmentally friendly and suitable for large-scale industrial production.
[0017] (2) The iron-nitrogen-doped magnetic wheat straw biochar catalyst prepared in this invention has abundant surface active sites, well-developed pore structure, and large specific surface area. It significantly improves the efficiency of peracetic acid and ferrate in degrading phenol and sodium dichlorophenate. This biochar has great application potential in the removal of new pollutants. Attached Figure Description
[0018] Figure 1 Here is a SEM image of the iron-nitrogen-doped biochar material prepared in Example 1;
[0019] Figure 2 Graphs showing the effects of different biochar catalysts on the degradation of DCF by ferrate;
[0020] Figure 3 Graphs showing the effects of different biochars on the degradation of DCF by peracetic acid;
[0021] Figure 4 This image shows the separation effect of iron-nitrogen-doped biochar under an external magnetic field. Detailed Implementation
[0022] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0023] The implementation method of the present invention is as follows:
[0024] Example 1:
[0025] A method for preparing iron-nitrogen-doped magnetic wheat straw biochar includes the following steps:
[0026] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0027] (2) Dissolve ferric chloride hexahydrate and urea in ultrapure water at a weight ratio of 1:1. After complete dissolution, add an equal weight of 200-mesh wheat straw powder and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 160°C for 10 hours. After hydrothermal treatment, dry the mixture in an oven at 60°C for 12 hours.
[0028] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 Increase the temperature to 700℃ at a rate of 100°C and maintain for 2 hours.
[0029] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain Fe-N-BC.
[0030] Example 2:
[0031] A method for preparing iron-nitrogen-doped magnetic wheat straw biochar includes the following steps:
[0032] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0033] (2) Dissolve ferric chloride hexahydrate and urea in ultrapure water at a weight ratio of 1:0.5. After complete dissolution, add 200-mesh wheat straw powder (4 times the weight of ferric chloride hexahydrate) and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 120°C for 12 hours. After hydrothermal treatment, dry the mixture in an oven at 50°C for 12 hours.
[0034] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 Increase the temperature to 700℃ at a rate of 100°C and maintain for 2 hours.
[0035] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain Fe-N-BC.
[0036] Example 3:
[0037] A method for preparing iron-nitrogen-doped magnetic wheat straw biochar includes the following steps:
[0038] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0039] (2) Dissolve ferric chloride hexahydrate and urea in ultrapure water at a weight ratio of 1:2. After complete dissolution, add 200-mesh wheat straw powder (twice the weight of ferric chloride hexahydrate) and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 180°C for 10 hours. After hydrothermal treatment, dry the mixture in an oven at 70°C for 12 hours.
[0040] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 Increase the temperature to 700℃ at a rate of 100°C and maintain for 2 hours.
[0041] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain Fe-N-BC.
[0042] Example 4:
[0043] A method for preparing iron-nitrogen-doped magnetic wheat straw biochar includes the following steps:
[0044] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0045] (2) Dissolve ferric chloride hexahydrate and urea in ultrapure water at a weight ratio of 1:0.5. After complete dissolution, dissolve 0.5 times the weight of ferric chloride hexahydrate in 200-mesh wheat straw powder and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 120°C for 12 hours. After hydrothermal treatment, dry the mixture in an oven at 50°C for 12 hours.
[0046] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 Increase the temperature to 700℃ at a rate of 100°C and maintain for 2 hours.
[0047] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain Fe-N-BC.
[0048] Example 5:
[0049] A method for preparing iron-nitrogen-doped magnetic wheat straw biochar includes the following steps:
[0050] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0051] (2) Dissolve ferric chloride hexahydrate and urea in ultrapure water at a weight ratio of 1:1. After complete dissolution, dissolve twice the amount of 200-mesh wheat straw powder (ferric chloride hexahydrate) and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 160°C for 10 hours. After hydrothermal treatment, dry the mixture in an oven at 60°C for 12 hours.
[0052] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 The temperature was increased to 950℃ at a rate of 1.5 h and held for 1.5 h.
[0053] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain Fe-N-BC.
[0054] Example 6:
[0055] A method for preparing iron-nitrogen-doped magnetic wheat straw biochar includes the following steps:
[0056] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0057] (2) Dissolve ferric chloride hexahydrate and urea in ultrapure water at a weight ratio of 1:1. After complete dissolution, add 200-mesh wheat straw powder (twice the weight of ferric chloride hexahydrate) and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 160°C for 10 hours. After hydrothermal treatment, dry the mixture in an oven at 60°C for 12 hours.
[0058] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 Increase the temperature to 800℃ at a rate of 100°C and maintain for 2 hours.
[0059] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain Fe-N-BC.
[0060] Example 7:
[0061] A method for preparing iron-nitrogen-doped magnetic wheat straw biochar includes the following steps:
[0062] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0063] (2) Dissolve ferric chloride hexahydrate and urea in ultrapure water at a weight ratio of 1:1. After complete dissolution, add 200-mesh wheat straw powder (twice the weight of ferric chloride hexahydrate) and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 160°C for 10 hours. After hydrothermal treatment, dry the mixture in an oven at 60°C for 12 hours.
[0064] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 Increase the temperature to 600℃ at a rate of 100°C and maintain for 2 hours.
[0065] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain Fe-N-BC.
[0066] Example 8:
[0067] A method for preparing iron-nitrogen-doped magnetic wheat straw biochar includes the following steps:
[0068] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0069] (2) Dissolve ferric chloride hexahydrate and urea in ultrapure water at a weight ratio of 1:1. After complete dissolution, add 200-mesh wheat straw powder (twice the weight of ferric chloride hexahydrate) and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 160°C for 10 hours. After hydrothermal treatment, dry the mixture in an oven at 60°C for 12 hours.
[0070] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 The temperature was increased to 400℃ at a rate of 100°C and held for 3.5 hours.
[0071] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain Fe-N-BC.
[0072] Comparative Example 1:
[0073] A method for preparing wheat straw biochar includes the following steps:
[0074] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0075] (2) Place 200-mesh wheat straw powder into a tube furnace and heat it at 5°C for 5 minutes under a nitrogen atmosphere. -1 Increase the temperature to 700℃ at a rate of 100°C and maintain for 2 hours.
[0076] (3) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain BC.
[0077] Comparative Example 2:
[0078] A method for preparing iron-doped wheat straw biochar includes the following steps:
[0079] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0080] (2) Dissolve a certain amount of ferric chloride hexahydrate in ultrapure water. After complete dissolution, dissolve an equal weight of 200-mesh wheat straw powder and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 160°C for 10 hours. After hydrothermal treatment, place the mixture in an oven at 60°C for 12 hours to dry.
[0081] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 Increase the temperature to 700℃ at a rate of 100°C and maintain for 2 hours.
[0082] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain Fe-BC.
[0083] Comparative Example 3:
[0084] A method for preparing nitrogen-doped wheat straw biochar includes the following steps:
[0085] (1) Wash the wheat straw several times with deionized water and air dry it naturally. Crush the dried wheat straw with a plant crusher and sieve it through a 200-mesh sieve.
[0086] (2) Dissolve a certain amount of urea in ultrapure water. After complete dissolution, dissolve an equal weight of 200-mesh wheat straw powder and mix thoroughly. Pour the solution into a reaction vessel and place it in an oven at 160°C for 10 hours. After hydrothermal treatment, place the mixture in an oven at 60°C for 12 hours to dry.
[0087] (3) Place the solid powder obtained in step (2) into a tube furnace and heat it at 5°C for 5 min under a nitrogen atmosphere. -1 Increase the temperature to 700℃ at a rate of 100°C and maintain for 2 hours.
[0088] (4) After the biochar obtained in step (3) is cooled to room temperature, it is washed with ultrapure water and ethanol and then dried in a vacuum oven at 60°C for 12 hours. After drying, it is ground through a 200-mesh sieve to obtain N-BC.
[0089] Experimental Example 1: Surface Morphology Characteristics
[0090] according to Figure 1 As can be seen from the SEM images, the Fe-N-BC surface prepared in Example 1 exhibits a rich porous structure with a large number of interconnected pores. This may be due to the decomposition of urea during pyrolysis, which forms a fluffy and porous structure, and the surface is also covered with abundant iron compound particles.
[0091] Experimental Example 2: Experiments on the degradation of diclofenac sodium (DCF) wastewater by different prepared catalysts using ferrates
[0092] The biochar catalysts prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were used for the treatment of DCF-containing wastewater. The specific experimental methods are as follows:
[0093] 50 mg of the wheat straw biochar catalyst ((Fe-N-BC)) prepared in Example 1 was weighed and added to 100 mL of a 5 μM DCF solution, followed by 50 μM potassium ferrate solution. The solution was then placed in a constant temperature shaker at 25 °C and 500 rpm. Samples were taken at 0, 1, 2, 3, 6, 10, 15, and 25 min, and the DCF concentration in the solution at different time points was detected using high performance liquid chromatography (HPLC).
[0094] 50 mg of wheat straw biochar catalyst (BC) prepared in Comparative Example 1 was weighed and added to 100 mL of 5 μM DCF solution, followed by 50 μM potassium ferrate solution. The solution was then placed in a constant temperature shaker at 25 °C and 500 rpm. Samples were taken at 0, 1, 2, 3, 6, 10, 15, and 25 min, and the DCF concentration in the solution at different time points was detected using high performance liquid chromatography (HPLC).
[0095] 50 mg of the wheat straw biochar catalyst (Fe-BC) prepared in Comparative Example 2 was weighed and added to 100 mL of a 5 μM DCF solution, followed by 50 μM potassium ferrate solution. The solution was then placed in a constant-temperature shaker at 25 °C and 500 rpm. Samples were taken at 0, 1, 2, 3, 6, 10, 15, and 25 min, and the DCF concentration in the solution at different time points was detected using high-performance liquid chromatography (HPLC).
[0096] 50 mg of wheat straw biochar catalyst (N-BC) prepared in Comparative Example 3 was weighed and added to 100 mL of 5 μM DCF solution, followed by 50 μM potassium ferrate solution. The solution was then placed in a constant temperature shaker at 25 °C and 500 rpm. Samples were taken at 0, 1, 2, 3, 6, 10, 15, and 25 min, and the DCF concentration in the solution at different time points was detected using high performance liquid chromatography (HPLC).
[0097] Experimental results are as follows Figure 2 As shown.
[0098] Figure 2 The images show the activation effects of biochar catalysts prepared in Examples 1, 1, 2, and 3 on the degradation of DCF by ferrate. Figure 2As can be seen, potassium ferrate alone only achieves a DCF degradation rate of about 79% within 25 minutes, while the pure BC catalyzed potassium ferrate system in Comparative Example 1 achieves a DCF degradation rate of 82% within 25 minutes. Furthermore, the biochar N-BC and Fe-BC catalyzed potassium ferrate systems, after doping, achieve DCF degradation rates of 94% and 98% respectively within 25 minutes. In the activated ferrate degradation of DCF experiment, the Fe-N-BC prepared in Example 1 achieved a DCF removal rate of 97.8% within 10 minutes. These results demonstrate that the present invention effectively improves the catalytic performance of biochar by doping with iron and nitrogen elements, enhancing its ability to catalyze the degradation of DCF by ferrates and significantly shortening the reaction time. In addition, comparing Example 1 and Comparative Example 1, the separation effect of the catalyst after the reaction shows that Fe-N-BC has excellent magnetic properties and can be rapidly separated from the aqueous solution under an external magnetic field. Figure 4 ).
[0099] Experimental Example 3: Experiments on the degradation of diclofenac sodium (DCF) wastewater by peracetic acid using different prepared catalysts
[0100] The biochar catalysts prepared in Example 1 and Comparative Example 1 were used for the treatment of DCF-containing wastewater. The specific experimental methods are as follows:
[0101] 50 mg of the wheat straw biochar catalyst (Fe-N-BC) prepared in Example 1 was weighed and added to 100 mL of a 5 μM DCF solution, followed by 100 μM MPa solution. The solution was then placed in a constant-temperature shaker at 25 °C and 500 rpm. Samples were taken at 0, 3, 8, 15, and 25 min, and the DCF concentration in the solution at different time points was detected using high-performance liquid chromatography (HPLC).
[0102] 50 mg of wheat straw biochar catalyst (BC) prepared in Comparative Example 1 was weighed and added to 100 mL of 5 μM DCF solution, followed by 100 μM MPa solution. The solution was then placed in a constant temperature shaker at 25 °C and 500 rpm. Samples were taken at 0, 3, 8, 15, and 25 min, and the DCF concentration in the solution at different time points was detected using high performance liquid chromatography (HPLC).
[0103] Experimental results are as follows Figure 3 As shown.
[0104] Figure 3 The images show the activation effects of the biochar catalysts prepared in Example 1 and Comparative Example 1 on the degradation of DCF by ferrate. From... Figure 3As can be seen, PAA alone has almost no degradation effect on DCF within 25 minutes, while the pure BC catalyzed potassium ferrate system in Comparative Example 1 achieved a DCF degradation rate of 40.1% within 25 minutes. Furthermore, the Fe-N-BC biochar doped in Example 1 achieved a DCF removal rate of 44.8% within 3 minutes and 80.7% within 25 minutes in the PAA-activated DCF degradation experiment. These results demonstrate that the present invention effectively improves the catalytic performance of biochar by doping it with iron and nitrogen elements, thereby enhancing its ability to catalyze the degradation of DCF by peracetic acid.
[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. Use of an iron-nitrogen doped magnetic wheat straw biochar catalyst, characterized in that, Application of iron-nitrogen-doped magnetic wheat straw biochar catalyst for the catalytic degradation of diclofenac sodium wastewater by peracetic acid or ferrate; The preparation method of the iron-nitrogen-doped magnetic wheat straw biochar catalyst includes the following steps: (1) Dissolve ferric chloride hexahydrate and urea in ultrapure water. After complete dissolution, dissolve 200-mesh wheat straw powder in the solution and mix evenly. The mass ratio of ferric chloride hexahydrate: urea: wheat straw powder is 1:1:
1. Pour the solution into a reaction vessel and perform hydrothermal treatment. After hydrothermal treatment, the reaction solution is separated and dried to obtain solid powder. (2) Under the protection of inert gas, the solid powder obtained in step (1) is carbonized, cooled, washed with ultrapure water and ethanol, dried and ground to obtain iron-nitrogen doped magnetic wheat straw biochar catalyst.
2. Use of the Fe and N doped magnetic wheat straw biochar catalyst according to claim 1, characterized in that, In step (1), the hydrothermal conditions are 120-180℃ for 8-12 hours.
3. The use of the Fe and N-doped magnetic wheat straw biochar catalyst according to claim 1, characterized in that, The drying in step (1) is vacuum drying, with a drying temperature of 50-70℃ and a drying time of 12h.
4. The use of the Fe and N-doped magnetic wheat straw biochar catalyst according to claim 1, characterized in that, The carbonization temperature in step (2) is 400-950°C, the time for maintaining the carbonization temperature is 1.5-3.5h, and the heating rate for heating to the carbonization temperature is 5°C / min -1 .