Magnetic biochar catalyst, preparation method thereof and application of magnetic biochar catalyst in degradation of antibiotic wastewater

Abstract

The invention relates to the technical field of sewage treatment, and provides a magnetic biochar catalyst and a preparation method and application thereof in degradation of antibiotic wastewater, and the magnetic biochar catalyst is prepared from the following raw materials in parts by weight: 4-6 parts of bagasse, 4-6 parts of pomelo peel, 4-6 parts of orange peel, 5-7 parts of soluble ferric salt, 5-7 parts of soluble manganese salt, 13-17 parts of chitosan, 4-6 parts of bacillus cereus powder and 4-6 parts of alcaligenes powder. According to the application, biochar formed by pyrolysis of agricultural wastes such as bagasse and chitosan cooperate with adsorption, tetracycline in wastewater is rapidly enriched, the local concentration is increased, and the toxicity of tetracycline to microorganisms is reduced; the strain can reduce the toxicity of pollutants and improve the utilization efficiency of a chemical oxidant; the soluble metal salt activates ozone and persulfate to deeply oxidize tetracycline. It can be seen that the magnetic biochar catalyst achieves efficient removal of antibiotic pollutants through the synergistic effect of physical adsorption, biodegradation and chemical oxidation.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a magnetic biochar catalyst, a preparation method thereof, and application thereof in degrading antibiotic wastewater. Background Art

[0002] Antibiotics are widely used in medicine and animal husbandry, generating large quantities of highly toxic, recalcitrant wastewater. Conventional wastewater treatment processes struggle to break down the chemical structure of antibiotics, resulting in low removal rates. Most antibiotics are bioaccumulative. For example, tetracyclines have a half-life of several weeks in the environment. Untreated discharge or reuse can lead to accumulation in ecosystems, posing a threat to human health and damaging aquatic ecosystems.

[0003] Currently, existing antibiotic treatment technologies face significant limitations. While physical adsorption can rapidly enrich pollutants, it carries the risk of secondary contamination after adsorption saturation. Advanced oxidation processes (ADPs) are subject to high operating costs due to catalyst deactivation and excessive oxidant consumption. Biodegradation is limited by the strong inhibitory effect of tetracycline on microorganisms, with degradation efficiencies often below 30%. While the mainstream "physical adsorption-chemical oxidation" combined strategy can improve treatment efficiency, it wastes resources due to excessive oxidant input. In recent years, agricultural waste has opened up new avenues for resource-based treatment as a low-cost adsorption carrier, and research on the domestication of antibiotic-resistant strains has also made progress. However, their practical application in wastewater treatment remains constrained by factors such as high substrate toxicity and competition for carbon sources. Therefore, a multi-stage synergistic system integrating adsorption enrichment, biological pretreatment, and deep chemical oxidation is urgently needed to achieve the harmless treatment of tetracycline while reducing treatment costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a magnetic biochar catalyst, a preparation method thereof and its application in the degradation of antibiotic wastewater. By combining physical, chemical and biological methods, the resource utilization of agricultural waste is realized, and an efficient and low-cost technical solution for the treatment of antibiotic wastewater is provided.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a magnetic biochar catalyst, which is prepared from the following raw materials in parts by weight: 4-6 parts of bagasse, 4-6 parts of grapefruit peel, 4-6 parts of orange peel, 5-7 parts of soluble iron salt, 5-7 parts of soluble manganese salt, 13-17 parts of chitosan, 4-6 parts of Bacillus cereus powder and 4-6 parts of Bacillus alcaligenes powder.

[0007] Preferably, the soluble iron salt includes ferric chloride or ferric nitrate, the soluble manganese salt includes manganese chloride or manganese nitrate, and the concentration of Bacillus cereus in the Bacillus cereus powder is 10 9 ~10 11CFU / g; the concentration of Alcaligenes in the Alcaligenes powder is 10 9 ~10 11 CFU / g.

[0008] The present invention also provides a method for preparing the magnetic biochar catalyst, comprising the following steps:

[0009] (1) drying sugarcane bagasse, grapefruit peel, and orange peel, crushing them, and sieving them to obtain raw material powder;

[0010] (2) mixing a soluble iron salt, a soluble manganese salt, a raw material powder, and water to obtain a mixture;

[0011] (3) drying the mixture, crushing it, and pyrolyzing it to obtain a carbonized product;

[0012] (4) The carbonized product is washed, dried, crushed, sieved, and then mixed with chitosan, Bacillus cereus powder, and Bacillus alcaligenes powder to obtain a magnetic biochar catalyst.

[0013] Preferably, the drying temperature in step (1) is 65-75° C., the drying time is 8-9 h, and an 80-120 mesh sieve is used for screening.

[0014] Preferably, the mixing time in step (2) is 4 to 5 hours, and the mixing speed is 200 to 300 r / min.

[0015] Preferably, the drying temperature in step (3) is 60-80°C, the drying time is 5-7h, and the pyrolysis treatment method is: heating to 550-650°C at a heating rate of 4-6°C / min, maintaining for 40-80min, and naturally cooling to room temperature; the pyrolysis treatment process is carried out under a nitrogen atmosphere, and the flow rate of the nitrogen is 180-220mL / min.

[0016] Preferably, the washing method in step (4) is: washing with water 4 to 8 times to remove ash, the drying temperature is 60 to 80° C., the drying time is 1 to 3 hours, and an 80 to 120 mesh sieve is used for screening.

[0017] The present invention also provides use of the magnetic biochar catalyst or the magnetic biochar catalyst prepared by the preparation method in treating antibiotic wastewater.

[0018] The present invention also provides a method for treating antibiotic wastewater, comprising the following steps:

[0019] A. adding the magnetic biochar catalyst or the magnetic biochar catalyst prepared by the preparation method into the wastewater containing antibiotics, stirring, and standing for 50 to 70 minutes to obtain a primary treatment liquid;

[0020] B introducing ozone into the primary treatment liquid for 25-35 min to obtain a secondary treatment liquid;

[0021] C adding a persulfate oxidant into the secondary treatment liquid, and obtaining a final wastewater treatment liquid after reacting for 25-35 min.

[0022] Preferably, the concentration of the magnetic biochar catalyst in the wastewater in step A is 100-300 mg / L, and the pH of the wastewater is 6-9;

[0023] The flow rate of the ozone introduced in step B is 0.6-1.0 L / min;

[0024] The concentration of the persulfate oxidant in step C is 300-1500 mg / L, the reaction temperature is 20-30℃, and the type of the antibiotic is tetracycline.

[0025] The present application has the following advantages:

[0026] The catalyst of the present application can efficiently degrade antibiotics in wastewater through the following synergistic mechanism:

[0027] (1) The biochar prepared by pyrolysis of agricultural waste such as sugarcane residue, pomelo peel, and orange peel has excellent adsorption performance for tetracycline; chitosan, as a natural cationic polysaccharide, can significantly enhance the adsorption capacity for tetracycline by virtue of its rich amino and hydroxyl functional groups through electrostatic attraction, hydrogen bonding and chelation effect. Under the synergistic action of the two, tetracycline in wastewater is rapidly enriched on the surface and in the pores of the catalyst, greatly increasing the local concentration and effectively overcoming the problem of insufficient reaction efficiency caused by low tetracycline concentration in water. At the same time, the adsorption process reduces the toxicity of tetracycline to microorganisms, improves the survival rate of strains, and creates favorable conditions for subsequent biological degradation.

[0028] (2) Bacillus cereus powder and Alcaligenes sp. powder have the characteristics of efficient degradation of organic matter. After biological pretreatment, the toxicity of the target pollutants in the wastewater is reduced, and the molecular structure is simplified, which significantly improves the utilization efficiency of the chemical oxidant, thereby reducing the amount of oxidant. The magnetic oxides generated by the conversion of soluble iron salt and manganese salt can efficiently activate per-ozone and persulfate to produce strong oxidizing substances such as hydroxyl radicals, achieving deep oxidative degradation of tetracycline.

[0029] (3) It is worth noting that ozone and persulfate can also inactivate Bacillus cereus and Bacillus alcaligenes during the oxidative degradation process, thus avoiding secondary pollution caused by excessive proliferation of strains. Furthermore, the magnetic biochar catalyst prepared by the present invention can achieve rapid and efficient separation and recovery through the action of an external magnetic field after completing the treatment of antibiotic wastewater. Compared with traditional catalyst separation methods, such as filtration and centrifugation, the magnetic recovery operation is simpler and has lower energy consumption. It can effectively reduce the catalyst loss in the separation process, improve the reuse rate of the catalyst, and further reduce the cost of wastewater treatment. At the same time, it also avoids the secondary pollution problem that may arise in the separation process, which is conducive to the greening and sustainability of the antibiotic wastewater treatment process. Therefore, the magnetic biochar catalyst proposed in this application achieves efficient removal and safe disposal of antibiotic pollutants through a multi-stage synergistic mechanism of physical adsorption, biodegradation and chemical oxidation. DETAILED DESCRIPTION

[0030] The present invention provides a magnetic biochar catalyst, which is prepared from the following raw materials in parts by weight: 4-6 parts of bagasse, 4-6 parts of grapefruit peel, 4-6 parts of orange peel, 5-7 parts of soluble iron salt, 5-7 parts of soluble manganese salt, 13-17 parts of chitosan, 4-6 parts of Bacillus cereus powder and 4-6 parts of Bacillus alcaligenes powder.

[0031] In the present invention, the soluble iron salt preferably includes ferric chloride or ferric nitrate, more preferably includes ferric chloride, the soluble manganese salt preferably includes manganese chloride or manganese nitrate, more preferably manganese chloride, and the concentration of Bacillus cereus in the Bacillus cereus powder is preferably 10 9 ~10 11 CFU / g, more preferably 10 10 CFU / g; the concentration of Alcaligenes in the Alcaligenes powder is preferably 10 9 ~10 11 CFU / g, more preferably 10 10 CFU / g.

[0032] The present invention also provides a method for preparing the magnetic biochar catalyst, comprising the following steps:

[0033] (1) drying sugarcane bagasse, grapefruit peel, and orange peel, crushing them, and sieving them to obtain raw material powder;

[0034] (2) mixing a soluble iron salt, a soluble manganese salt, a raw material powder, and water to obtain a mixture;

[0035] (3) drying the mixture, crushing it, and pyrolyzing it to obtain a carbonized product;

[0036] (4) washing, drying, crushing, and sieving the carbonization product, and mixing the carbonization product with chitosan, Bacillus cereus powder, and Alcaligenes faecalis powder to obtain the magnetic biochar catalyst.

[0037] In the present application, the drying temperature in step (1) is preferably 65-75 DEG C, further preferably 70 DEG C, the drying time is preferably 8-9 h, further preferably 8.5 h, and the sieving is preferably performed using a 80-120 mesh sieve, further preferably a 100 mesh sieve.

[0038] In the present application, the mixing time in step (2) is preferably 4-5 h, further preferably 4.5 h, and the mixing speed is preferably 200-300 r / min, further preferably 250 r / min.

[0039] In the present application, the drying temperature in step (3) is preferably 60-80 DEG C, further preferably 70 DEG C, the drying time is preferably 5-7 h, further preferably 6 h, the pyrolysis treatment is preferably performed by increasing the temperature to 550-650 DEG C at a rate of 4-6 DEG C / min, maintaining the temperature for 40-80 min, and naturally cooling to room temperature, further preferably by increasing the temperature to 600 DEG C at a rate of 5 DEG C / min, maintaining the temperature for 60 min, and naturally cooling to room temperature, and the pyrolysis treatment is performed in a nitrogen atmosphere, preferably at a flow rate of 180-220 mL / min, further preferably 200 mL / min.

[0040] In the present application, the washing method in step (4) is preferably washing with water 4-8 times to remove ash, further preferably washing with water 6 times to remove ash, the drying temperature is preferably 60-80 DEG C, further preferably 70 DEG C, the drying time is preferably 1-3 h, further preferably 2 h, and the sieving is preferably performed using a 80-120 mesh sieve, further preferably a 100 mesh sieve.

[0041] The present application also provides the use of the magnetic biochar catalyst or the magnetic biochar catalyst prepared by the preparation method in treating antibiotic wastewater.

[0042] The present application also provides a method for treating antibiotic wastewater, comprising the following steps:

[0043] A) adding the magnetic biochar catalyst or the magnetic biochar catalyst prepared by the preparation method into wastewater containing antibiotics, stirring, and standing for 50-70 min to obtain a primary treatment liquid;

[0044] B) passing ozone into the primary treatment liquid for 25-35 min to obtain a secondary treatment liquid;

[0045] C. Add persulfate oxidant to the secondary treatment liquid and react for 25 to 35 minutes to obtain the final wastewater treatment liquid.

[0046] In the present invention, the concentration of the magnetic biochar catalyst in the wastewater in step A is preferably 100-300 mg / L, more preferably 200 mg / L, and the pH of the wastewater is preferably 6-9, more preferably 7-8;

[0047] The ozone flow rate in step B is preferably 0.6 to 1.0 L / min, more preferably 0.8 L / min;

[0048] The persulfate oxidant in step C is preferably peroxymonosulfate, and the concentration of the persulfate oxidant is preferably 300-1500 mg / L, more preferably 500-1200 mg / L, and even more preferably 900 mg / L. The reaction temperature is preferably 20-30°C, and even more preferably 25°C. The type of antibiotic is tetracycline.

[0049] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0050] Example 1

[0051] A magnetic biochar catalyst is prepared from the following raw materials in parts by weight: 5 parts of bagasse, 5 parts of grapefruit peel, 5 parts of orange peel, 6 parts of soluble iron salt, 6 parts of soluble manganese salt, 15 parts of chitosan, 5 parts of Bacillus cereus powder and 5 parts of Bacillus alcaligenes powder.

[0052] The soluble iron salt is ferric chloride, the soluble manganese salt is manganese chloride, and the concentration of Bacillus cereus in the Bacillus cereus powder is 10 10 CFU / g; the concentration of Alcaligenes in the Alcaligenes powder is 10 10 CFU / g.

[0053] The preparation method of the magnetic biochar catalyst comprises the following steps:

[0054] (1) Sugarcane bagasse, grapefruit peel, and orange peel were dried at 70°C for 8.5 h, crushed, and passed through a 100-mesh sieve to obtain raw material powder;

[0055] (2) mixing the soluble iron salt, the soluble manganese salt, the raw material powder and water at a rotation speed of 250 r / min for 4.5 hours to obtain a mixture;

[0056] (3) drying the mixture at 70°C for 6 hours, crushing it, and pyrolyzing it to obtain a carbonized product; the pyrolysis treatment method is as follows: heating the temperature to 600°C at a rate of 5°C / min, maintaining it for 60 minutes, and naturally cooling it to room temperature; the entire pyrolysis treatment process is carried out under a nitrogen atmosphere with a nitrogen flow rate of 200 mL / min;

[0057] (4) The carbonized product was washed with water six times to remove ash, dried at 70°C for 2 h, crushed, passed through a 100-mesh sieve, and mixed with chitosan, Bacillus cereus powder, and Bacillus alcaligenes powder to obtain magnetic biochar catalyst 1.

[0058] Example 2

[0059] A magnetic biochar catalyst is prepared from the following raw materials in parts by weight: 4 parts of bagasse, 4 parts of grapefruit peel, 4 parts of orange peel, 5 parts of soluble iron salt, 5 parts of soluble manganese salt, 13 parts of chitosan, 4 parts of Bacillus cereus powder and 4 parts of Bacillus alcaligenes powder.

[0060] The soluble iron salt is ferric chloride, the soluble manganese salt is manganese nitrate, and the concentration of Bacillus cereus in the Bacillus cereus powder is 10 9 CFU / g; the concentration of Alcaligenes in the Alcaligenes powder is 10 9 CFU / g.

[0061] The preparation method of the magnetic biochar catalyst comprises the following steps:

[0062] (1) Sugarcane bagasse, grapefruit peel, and tangerine peel were dried at 65°C for 8 h, crushed, and passed through an 80-mesh sieve to obtain raw material powder;

[0063] (2) mixing the soluble iron salt, the soluble manganese salt, the raw material powder and water at a rotation speed of 200 r / min for 4 hours to obtain a mixture;

[0064] (3) drying the mixture at 60°C for 5 h, crushing it, and pyrolyzing it to obtain a carbonized product; the pyrolysis treatment method is as follows: heating the temperature to 550°C at a rate of 4°C / min, maintaining it for 40 min, and naturally cooling it to room temperature; the entire pyrolysis treatment process is carried out under a nitrogen atmosphere with a nitrogen flow rate of 180 mL / min;

[0065] (4) The carbonized product was washed with water four times to remove ash, dried at 60°C for 1 h, crushed, passed through an 80-mesh sieve, and mixed with chitosan, Bacillus cereus powder, and Bacillus alcaligenes powder to obtain magnetic biochar catalyst 2.

[0066] Example 3

[0067] A magnetic biochar catalyst is prepared from the following raw materials in parts by weight: 6 parts of bagasse, 6 parts of grapefruit peel, 6 parts of orange peel, 7 parts of soluble iron salt, 7 parts of soluble manganese salt, 17 parts of chitosan, 6 parts of Bacillus cereus powder and 6 parts of Bacillus alcaligenes powder.

[0068] The soluble iron salt is ferric nitrate, the soluble manganese salt is manganese chloride, and the concentration of Bacillus cereus in the Bacillus cereus powder is 10 11 CFU / g; the concentration of Alcaligenes in the Alcaligenes powder is 10 11 CFU / g.

[0069] The preparation method of the magnetic biochar catalyst comprises the following steps:

[0070] (1) Sugarcane bagasse, grapefruit peel, and orange peel were dried at 75°C for 9 h, crushed, and passed through a 120-mesh sieve to obtain raw material powder;

[0071] (2) mixing the soluble iron salt, the soluble manganese salt, the raw material powder and water at a rotation speed of 300 r / min for 5 hours to obtain a mixture;

[0072] (3) drying the mixture at 80°C for 7 hours, crushing it, and pyrolyzing it to obtain a carbonized product; the pyrolysis treatment method is as follows: heating the temperature to 650°C at a rate of 6°C / min, maintaining it for 80 minutes, and naturally cooling it to room temperature; the entire pyrolysis treatment process is carried out under a nitrogen atmosphere with a nitrogen flow rate of 220 mL / min;

[0073] (4) The carbonized product was washed with water 8 times to remove ash, dried at 80°C for 3 h, crushed, passed through a 120-mesh sieve, and mixed with chitosan, Bacillus cereus powder, and Bacillus alcaligenes powder to obtain magnetic biochar catalyst 3.

[0074] Comparative Example 1

[0075] The present embodiment differs from Example 1 in that chitosan is removed from the raw material. Other conditions are the same, and finally a magnetic biochar catalyst 4 is prepared.

[0076] Comparative Example 2

[0077] The present method differs from Example 1 in that the Bacillus cereus powder and Bacillus alcaligenes powder in the raw materials are removed. Other conditions remain the same, and finally a magnetic biochar catalyst 5 is prepared.

[0078] Comparative Example 3

[0079] The present embodiment differs from Example 1 in that the drying temperature in step (1) of the preparation method of the magnetic biochar catalyst is 85° C. and the drying time is 10 h. Other conditions are the same, and finally a magnetic biochar catalyst 6 is prepared.

[0080] Application Example 1

[0081] A. 16 mg of the magnetic biochar catalyst 1 prepared in Example 1 was added to 100 mL of an aqueous solution having a pH of 7 and a tetracycline concentration of 20 mg / L, stirred, and allowed to stand for 60 min to obtain a primary treatment solution.

[0082] B. Ozone is introduced into the primary treatment liquid at a flow rate of 0.8 L / min for 30 minutes while continuously stirring to obtain a secondary treatment liquid;

[0083] C. Add 90 mg of peroxymonosulfate to the secondary treatment liquid, continue stirring, and react at 25°C for 30 minutes to obtain the final wastewater treatment liquid;

[0084] D. Use a magnet to remove the remaining magnetic biochar catalyst from the final wastewater treatment solution.

[0085] Application Example 2

[0086] This embodiment method differs from Application Example 1 in that the step of "standing for 1 hour" in Step A is removed.

[0087] Application Example 3

[0088] This embodiment differs from Application Example 1 in that step B is removed.

[0089] Application Example 4

[0090] This embodiment differs from Application Example 1 in that step C is removed.

[0091] Application Example 5

[0092] The present embodiment differs from Application Example 1 in that the "magnetic biochar catalyst 1 prepared in Example 1" is replaced with the "magnetic biochar catalyst 4 prepared in Comparative Example 1".

[0093] Application Example 6

[0094] The present embodiment differs from Application Example 1 in that the "magnetic biochar catalyst 1 prepared in Example 1" is replaced with the "magnetic biochar catalyst 5 prepared in Comparative Example 2".

[0095] Application Example 7

[0096] The difference between this embodiment and Application Example 1 is that the "magnetic biochar catalyst 1 prepared in Example 1" is replaced with the "magnetic biochar catalyst 6 prepared in Comparative Example 3".

[0097] The changes in the tetracycline content in the solution under the catalyst systems of Application Examples 1 to 7 were tested (the tetracycline content in the initial solution was taken as 1). The experimental results are shown in Table 1.

[0098] Table 1 Changes in tetracycline content in solution under different catalyst systems (mg / L)

[0099]

[0100]

[0101] As shown in Table 1, the magnetic biochar catalyst provided in this application, leveraging the synergistic action of multiple strains, initially degrades tetracycline and other organic matter in wastewater, significantly enhancing the ability of the subsequent impregnation-loaded iron-manganese bimetallic active component coupled with ozone and persulfate to remove antibiotic pollutants. Compared to existing technologies, this antibiotic wastewater treatment method can more efficiently and thoroughly treat tetracycline wastewater.

[0102] As can be seen from the above examples, the present invention provides a magnetic biochar catalyst, a preparation method thereof, and its application in the degradation of antibiotic wastewater. The catalyst is prepared from the following raw materials in parts by weight: 4-6 parts of sugarcane bagasse, 4-6 parts of grapefruit peel, 4-6 parts of orange peel, 5-7 parts of soluble iron salt, 5-7 parts of soluble manganese salt, 13-17 parts of chitosan, 4-6 parts of Bacillus cereus powder, and 4-6 parts of Bacillus alcaligenes powder. In the present application, the biochar and chitosan formed by the pyrolysis of agricultural waste such as sugarcane bagasse synergistically adsorb and rapidly enrich tetracycline in the wastewater, increase the local concentration, and reduce its toxicity to microorganisms; the bacterial strain can reduce the toxicity of pollutants and improve the utilization efficiency of chemical oxidants; and the soluble metal salt activates perozone and persulfate to deeply oxidize tetracycline. It can be seen that the magnetic biochar catalyst of the present application achieves efficient removal of antibiotic pollutants through the synergistic effects of physical adsorption, biodegradation, and chemical oxidation.

[0103] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A magnetic biochar catalyst, characterized in that The invention is prepared from the following raw materials in parts by weight: 4-6 parts of bagasse, 4-6 parts of grapefruit peel, 4-6 parts of orange peel, 5-7 parts of soluble iron salt, 5-7 parts of soluble manganese salt, 13-17 parts of chitosan, 4-6 parts of Bacillus cereus powder and 4-6 parts of Bacillus alcaligenes powder.

2. The magnetic biochar catalyst according to claim 1, characterized in that The soluble iron salt includes ferric chloride or ferric nitrate, the soluble manganese salt includes manganese chloride or manganese nitrate, and the concentration of Bacillus cereus in the Bacillus cereus powder is 10 9 ~10 11 CFU / g; the concentration of Alcaligenes in the Alcaligenes powder is 10 9 ~10 11 CFU / g.

3. A method for preparing the magnetic biochar catalyst according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) drying sugarcane bagasse, grapefruit peel, and orange peel, crushing them, and sieving them to obtain raw material powder; (2) mixing a soluble iron salt, a soluble manganese salt, a raw material powder, and water to obtain a mixture; (3) drying the mixture, crushing it, and pyrolyzing it to obtain a carbonized product; (4) The carbonized product is washed, dried, crushed, sieved, and then mixed with chitosan, Bacillus cereus powder, and Bacillus alcaligenes powder to obtain a magnetic biochar catalyst.

4. The preparation method according to claim 3, characterized in that The drying temperature in step (1) is 65-75° C., the drying time is 8-9 hours, and an 80-120 mesh sieve is used for sieving.

5. The preparation method according to claim 4, characterized in that The mixing time in step (2) is 4 to 5 hours, and the mixing speed is 200 to 300 r / min.

6. The preparation method according to claim 3, characterized in that The drying temperature in step (3) is 60-80°C, the drying time is 5-7h, and the pyrolysis treatment method is: heating to 550-650°C at a rate of 4-6°C / min, maintaining for 40-80min, and naturally cooling to room temperature; the pyrolysis treatment process is carried out under a nitrogen atmosphere, and the flow rate of the nitrogen is 180-220mL / min.

7. The preparation method according to claim 6, characterized in that The washing method in step (4) is: washing with water 4 to 8 times to remove ash, the drying temperature is 60 to 80° C., the drying time is 1 to 3 hours, and an 80 to 120 mesh sieve is used for screening.

8. Use of the magnetic biochar catalyst according to any one of claims 1 to 2 or the magnetic biochar catalyst prepared by the preparation method according to any one of claims 3 to 7 in treating antibiotic wastewater.

9. A method for treating antibiotic wastewater, characterized in that: The steps include: A. adding the magnetic biochar catalyst according to any one of claims 1 to 2 or the magnetic biochar catalyst prepared by the preparation method according to any one of claims 3 to 8 into wastewater containing antibiotics, stirring, and standing for 50 to 70 minutes to obtain a primary treatment liquid; B. Pass ozone into the primary treatment liquid for 25 to 35 minutes to obtain the secondary treatment liquid; C. Add persulfate oxidant to the secondary treatment liquid and react for 25 to 35 minutes to obtain the final wastewater treatment liquid.

10. The method according to claim 9, characterized in that The concentration of the magnetic biochar catalyst in the wastewater in step A is 100-300 mg / L, and the pH of the wastewater is 6-9; The ozone flow rate in step B is 0.6-1.0 L / min; In step C, the concentration of the persulfate oxidant is 300-1500 mg / L, the reaction temperature is 20-30° C., and the type of the antibiotic is tetracycline.

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