Composition for catalytic degradation of oxytetracycline and preparation method thereof

Abstract

The present invention relates to the field of catalytic oxidation technology, and in particular to a composition for the catalytic degradation of oxytetracycline and a preparation method thereof. The composition for the catalytic degradation of oxytetracycline is composed of the following raw materials in parts by weight: 5 to 15 parts of chemically modified biochar, 15 to 45 parts of ferrous salt, 10 to 30 parts of metal sulfide, 5 to 15 parts of natural polymer colloid, 4 to 8 parts of tin-based metal carbide or titanium-based metal carbide, and 1 to 2 parts of polyethyleneimine. The composition for the catalytic degradation of oxytetracycline prepared by the present invention, by acetylation of biochar, is loaded with more active functional groups, thereby improving the ability of H2O2 to oxidatively degrade OTC. The composition for the catalytic degradation of oxytetracycline prepared by the present invention, wherein the biochar is loaded with tin-based and titanium-based metals at the same time, can significantly enhance the ability of H2O2 to oxidatively degrade OTC at low concentrations, and further enhance the ability of H2O2 to oxidatively degrade OTC at high concentrations.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic oxidation, and in particular to a composition for catalytic degradation of oxytetracycline and a preparation method thereof. Background Art

[0002] Oxytetracycline (OTC) is a broad-spectrum antibiotic synthesized by Streptomyces truncatula. It exhibits broad antimicrobial activity and is a rapid bacteriostatic agent, with bactericidal effects against certain bacteria at high concentrations. Due to its low cost and wide applicability, it is widely used in pharmaceutical therapy, animal husbandry, agriculture, and aquaculture as an antimicrobial, feed additive, and growth factor. With the widespread production and application of oxytetracycline, human consumption and dependence on it have increased. However, due to the structural characteristics and unique properties of oxytetracycline, conventional wastewater treatment processes are unable to effectively remove oxytetracycline from wastewater, ultimately entering the human body through the food chain, impacting human health. Toxicity studies have shown that antibiotics in water can lead to drug resistance and are toxic to many microorganisms. Numerous experimental results have also demonstrated that long-term exposure to antibiotics can produce toxic effects in microorganisms. Studies on the toxic effects of antibiotics have clearly demonstrated that antibiotics are potentially genotoxic agents, a finding confirmed by animal and microbial experiments. Antibiotics also generally inhibit chloroplast formation, chlorophyll production, and protein synthesis, adversely affecting the photosynthetic capacity, cell proliferation, and growth of microalgae. The main methods for removing antibiotics at present are as follows: adsorption, oxidation, membrane separation, biodegradation, etc. Oxidation refers to the use of light, electricity, ultrasound, oxidants, etc. to generate highly active free radicals in the system, and then remove organic pollutants through free radicals. Advanced oxidation technology mainly includes Fenton oxidation, ozone oxidation, photochemical oxidation (photocatalytic method), electrochemical oxidation, ultrasonic oxidation and catalytic wet oxidation. Advanced oxidation technology has many characteristics: (1) good oxidation effect, high efficiency and fast reaction speed; (2) easy to control reaction conditions and good stability; (3) wide range of applications and good removal effect of various pollutants; (4) can be combined with other procedures to improve this effect and reduce costs; (5) simple operation and easy management. Among them, ozone oxidation refers to adding O3 to wastewater and using the strong oxidizing property of O3 to cleave certain functional groups of antibiotics, thereby degrading, oxidizing and removing them. Electrochemical oxidation is the oxidation of antibiotics by hydroxyl, ozone and other oxidizing functional groups generated by electrolysis, or directly removing antibiotics by electrode reaction. Fenton oxidation is the process of reacting H2O2 with Fe 2+The combined system generates hydroxyl radicals (-OH) and other highly reactive oxygen species that degrade and remove antibiotics. The catalyst is a key factor in determining the effectiveness of Fenton oxidation. Biochar, due to its abundant oxygen-containing functional groups, persistent free radicals, and low cost, offers unparalleled advantages as a catalyst.

[0003] Biochar refers to the solid material produced by the pyrolysis of biomass materials at high temperatures. This solid material exhibits a stable structure, complex pore structure, large specific surface area, and a high concentration of oxygen-active groups. Biochar has excellent adsorption capacity for heavy metals, organic pollutants, and some ammonia nitrogen pollutants in water, soil, and other environments. Its production is simple, making it a common method for pollutant removal in natural environments. Currently, the primary method for producing biochar is high-temperature pyrolysis. During this process, biomass materials dry and dehydrate at temperatures between 0 and 200°C. Within the temperature range of 200 to 400°C, chemical bonds within the biomass begin to shift, and lignin and cellulose undergo continuous decomposition, forming amorphous carbon. As the temperature rises further (>400°C), more aromatic rings emerge. Biochar's characteristics include rich functional groups, well-developed pores, and a variety of components. It is commonly used as an adsorbent to remove various pollutants from the environment. Currently, researchers both domestically and internationally are using biochar as an adsorbent for environmental remediation and improvement. However, its activation properties are limited, necessitating further biochar modification. Currently, common biochar modification methods include physical modification, chemical modification, and biological modification. Chemical modification is one of the methods commonly used by researchers. Chemical modification refers to the addition of some acid, alkali, or redox reagents to change the physical and chemical properties of the biochar material, thereby improving the biochar's ability to remove pollutants.

[0004] Based on the above situation, the present invention proposes a composition for catalytic degradation of oxytetracycline and a preparation method thereof. Summary of the Invention

[0005] The object of the present invention is to provide a composition for catalytic degradation of oxytetracycline and a preparation method thereof.

[0006] To achieve the above-mentioned purpose, the present invention provides a composition for the catalytic degradation of oxytetracycline, which is composed of the following raw materials in parts by weight: 5 to 15 parts of chemically modified biochar, 15 to 45 parts of ferrous salt, 10 to 30 parts of metal sulfide, 5 to 15 parts of natural polymer colloid, 4 to 8 parts of tin-based metal carbide or titanium-based metal carbide, and 1 to 2 parts of polyethyleneimine.

[0007] The present invention also provides a method for preparing a composition for catalytic degradation of oxytetracycline, the preparation method comprising the following steps:

[0008] (1) Ferrous salt is mixed with water at a mass-liquid ratio of 1g:0.5L, and natural polymer colloid is added under stirring at a speed of 200-300rpm. After mixing, chemically modified biochar is added, and finally metal sulfide solution is added at a rate of 2-3 drops per second. The metal sulfide is pre-mixed with water at a mass-liquid ratio of 1g:20ml. After the metal sulfide solution is added, stirring is continued for 3h. The whole process is completed in a nitrogen atmosphere. After stirring, it is allowed to stand for 10-12h and dried to obtain biochar loaded with metal sulfide;

[0009] (2) Tin-based metal carbide or titanium-based metal carbide is mixed with anhydrous ethanol at a mass-to-liquid ratio of 1 g: 50-55 ml and stirred evenly, and then the biochar of metal sulfide is added. In a nitrogen protective atmosphere, the mixture is stirred at 30°C to 40°C for 30-35 minutes, and then polyethyleneimine is added. The mixture is continuously stirred at 60°C to 70°C for 2-2.5 hours, and then filtered, washed three times with deionized water, and vacuum freeze-dried for 10-12 hours to obtain the product.

[0010] Preferably, the ferrous salt comprises one of ferrous oxide, ferrous hydroxide, ferrous sulfate, and ferrous chloride. In one embodiment, the ferrous salt is ferrous sulfate heptahydrate.

[0011] Preferably, the metal sulfide comprises one of sodium sulfide and potassium sulfide. In one embodiment, the metal sulfide is sodium sulfide nonahydrate.

[0012] Preferably, the chemically modified biochar comprises one of acidified biochar, alkaline biochar, acetylated biochar, and oxidized biochar. In one embodiment, the chemically modified biochar is acetylated biochar.

[0013] Preferably, the acetylated biochar is prepared by the following method:

[0014] (1) The washed and dried chestnut shells were crushed with a crusher and passed through a 40-mesh crusher, and then placed in a tubular furnace under a nitrogen atmosphere and heated at 10°C / min-1 to a set temperature for pyrolysis. After reaching the set temperature, the shells were kept warm for 2.0 to 2.5 hours, and the set temperature was 700 to 750°C. The shells were then cooled to room temperature to obtain a biochar precursor.

[0015] (2) Take the biochar precursor and add a mixed solution of glacial acetic acid / acetic anhydride at a mass-to-liquid ratio of 1g:10-12ml to the biochar precursor. The volume ratio of glacial acetic acid to acetic anhydride is 1:1. After fully swelling for 30-40 minutes, add 2% sulfuric acid at a mass-to-liquid ratio of 1:0.5-0.8ml to the biochar precursor. Stir and reflux for 5-6 hours, then filter, wash with deionized water until neutral, and dry in an oven at 65±5℃ to constant weight to obtain acetylated biochar.

[0016] Preferably, the tin-based metal carbide or titanium-based metal carbide is tin titanium carbide, with a chemical formula of Ti2SnC. The particle size of the tin titanium carbide is 200 mesh to 300 mesh, and the purity is ≥98%.

[0017] Preferably, the natural polymer colloid comprises one of gum arabic, gum tragacanth, xanthan gum, and guar gum. In one embodiment, the natural polymer colloid is gum arabic.

[0018] Preferably, the composition for catalytic degradation of oxytetracycline is composed of the following raw materials in parts by weight: 5 to 15 parts of acetylated biochar, 15 to 45 parts of ferrous sulfate heptahydrate, 10 to 30 parts of sodium sulfide nonahydrate, 5 to 15 parts of gum arabic, 4 to 8 parts of titanium tin carbide, and 1 to 2 parts of polyethyleneimine.

[0019] Preferably, the preparation method of the composition for catalytic degradation of oxytetracycline comprises the following steps:

[0020] (1) The cleaned and dried chestnut shells were crushed with a crusher and passed through 40 mesh, and then placed in a tube furnace under a nitrogen atmosphere at 10 ° C / min. -1 The temperature is raised to the set temperature for pyrolysis, and after reaching the set temperature, the temperature is kept at 700-750°C for 2.0-2.5 hours, and then cooled to room temperature to obtain a biochar precursor;

[0021] (2) Take the biochar precursor, add a mixed solution of glacial acetic acid / acetic anhydride at a mass-to-liquid ratio of 1g:10-12ml to the biochar precursor, and the volume ratio of glacial acetic acid to acetic anhydride is 1:1. After fully swelling for 30-40min, add 2% sulfuric acid at a mass-to-liquid ratio of 1:0.5-0.8ml to the biochar precursor, stir and reflux for 5-6h, then filter, wash with deionized water until neutral, and dry in an oven at 65±5℃ to constant weight to obtain acetylated biochar;

[0022] (3) Ferrous sulfate heptahydrate was mixed with water at a mass-liquid ratio of 1g:0.5L, and gum arabic was added while stirring at a speed of 200-300rpm. After mixing, acetylated biochar was added, and finally sodium sulfide nonahydrate solution was added at a rate of 2-3 drops per second. The sodium sulfide nonahydrate solution was previously mixed with water at a mass-liquid ratio of 1g:20ml using sodium sulfide nonahydrate. After the sodium sulfide nonahydrate solution was added, stirring was continued for 3h. The whole process was completed in a nitrogen atmosphere. After stirring, it was allowed to stand for 10-12h and dried to obtain biochar loaded with ferrous sulfide.

[0023] (4) Titanium tin carbide and anhydrous ethanol were mixed at a mass-liquid ratio of 1 g: 50-55 ml and stirred evenly, and then biochar loaded with ferrous sulfide was added. In a nitrogen protective atmosphere, the mixture was stirred at 30°C to 40°C for 30-35 minutes, and then polyethyleneimine was added. The mixture was stirred at 60°C to 70°C for 2-2.5 hours, and then filtered, washed three times with deionized water, and vacuum freeze-dried for 10-12 hours.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The composition for catalytic degradation of oxytetracycline prepared by the present invention acetylates biochar so that it is loaded with more active functional groups, thereby improving the ability of H2O2 to oxidatively degrade OTC.

[0026] 2. The composition for catalytic degradation of oxytetracycline prepared by the present invention, in which the biochar is loaded with tin-based and titanium-based metals at the same time, can significantly enhance the ability of H2O2 oxidative degradation at low concentrations of OTC, and further enhance the ability of H2O2 oxidative degradation at high concentrations of OTC.

[0027] 3. The raw materials of the present invention are sufficient in China and are reasonably priced, so that there is no high cost limit for large-scale production; at the same time, the composition used for catalytic degradation of oxytetracycline is simple and the overall production cost is not high, which is conducive to large-scale industrial production. DETAILED DESCRIPTION

[0028] Example 1

[0029] Weigh the specific raw materials according to Table 1. The preparation steps are as follows:

[0030] (1) The cleaned and dried chestnut shells were crushed with a crusher and passed through 40 mesh, and then placed in a tube furnace under a nitrogen atmosphere at 10 ° C / min. -1 The temperature was raised to the set temperature for pyrolysis, and after reaching the set temperature, the temperature was kept at 750°C for 2.0 h, and then cooled to room temperature to obtain a biochar precursor;

[0031] (2) Take the biochar precursor and add a mixed solution of glacial acetic acid / acetic anhydride at a mass-to-liquid ratio of 1g:10ml to the biochar precursor. The volume ratio of glacial acetic acid to acetic anhydride is 1:1. After sufficient swelling for 30 minutes, add 2% sulfuric acid at a mass-to-liquid ratio of 1:0.5ml to the biochar precursor. Stir and reflux for 5 hours, then filter, wash with deionized water until neutral, and dry in an oven at 65±5℃ to constant weight to obtain acetylated biochar;

[0032] (3) Mix ferrous sulfate heptahydrate with water at a mass-liquid ratio of 1g:0.5L, add gum arabic while stirring at a speed of 200rpm, add acetylated biochar after mixing, and finally add sodium sulfide nonahydrate solution at a rate of 2 to 3 drops per second. The sodium sulfide nonahydrate solution is pre-mixed with water at a mass-liquid ratio of 1g:20ml using sodium sulfide nonahydrate. After the sodium sulfide nonahydrate solution is added, continue stirring for 3h. The whole process is completed in a nitrogen atmosphere. After stirring, let it stand for 10h and dry to obtain biochar loaded with ferrous sulfide;

[0033] (4) Titanium tin carbide and anhydrous ethanol were mixed at a mass-liquid ratio of 1 g:50 ml and stirred evenly, and then biochar loaded with ferrous sulfide was added. In a nitrogen protective atmosphere, the mixture was stirred at 30 ° C for 35 minutes, and then polyethyleneimine was added. The mixture was stirred at 60 ° C for 2.5 hours, and then filtered, washed three times with deionized water, and vacuum freeze-dried for 10 hours.

[0034] Example 2

[0035] Weigh the specific raw materials according to Table 1. The preparation steps are as follows:

[0036] (1) The cleaned and dried chestnut shells were crushed with a crusher and passed through 40 mesh, and then placed in a tube furnace under a nitrogen atmosphere at 10 ° C / min. -1 The temperature was raised to the set temperature for pyrolysis, and after reaching the set temperature, the temperature was kept at 700°C for 2.5 hours, and then cooled to room temperature to obtain a biochar precursor;

[0037] (2) Take the biochar precursor and add a mixed solution of glacial acetic acid / acetic anhydride at a mass-to-liquid ratio of 1g:12ml to the biochar precursor. The volume ratio of glacial acetic acid to acetic anhydride is 1:1. After fully swelling for 40 minutes, add 2% sulfuric acid at a mass-to-liquid ratio of 1:0.8ml to the biochar precursor. Stir and reflux for 6 hours, then filter, wash with deionized water until neutral, and dry in an oven at 65±5℃ to constant weight to obtain acetylated biochar;

[0038] (3) Ferrous sulfate heptahydrate was mixed with water at a mass-liquid ratio of 1 g: 0.5 L, and gum arabic was added while stirring at a speed of 300 rpm. After mixing, acetylated biochar was added, and finally sodium sulfide nonahydrate solution was added at a rate of 2 to 3 drops per second. The sodium sulfide nonahydrate solution was previously mixed with water at a mass-liquid ratio of 1 g: 20 ml with sodium sulfide nonahydrate. After the sodium sulfide nonahydrate solution was added, stirring was continued for 3 hours. The entire process was completed in a nitrogen atmosphere. After stirring, it was allowed to stand for 12 hours and dried to obtain biochar loaded with ferrous sulfide.

[0039] (4) Titanium tin carbide and anhydrous ethanol were mixed at a mass-liquid ratio of 1 g:55 ml and stirred evenly, and then biochar loaded with ferrous sulfide was added. In a nitrogen atmosphere, the mixture was stirred at 40 ° C for 30 min, and then polyethyleneimine was added. The mixture was stirred at 70 ° C for 2 h, and then filtered, washed three times with deionized water, and vacuum freeze-dried for 12 h.

[0040] Example 3

[0041] Weigh the specific raw materials according to Table 1. The preparation steps are as follows:

[0042] (1) The cleaned and dried chestnut shells were crushed with a crusher and passed through 40 mesh, and then placed in a tube furnace under a nitrogen atmosphere at 10 ° C / min. -1 The temperature was raised to the set temperature for pyrolysis, and after reaching the set temperature, the temperature was kept at 750°C for 2.5 hours, and then cooled to room temperature to obtain a biochar precursor;

[0043] (2) Take the biochar precursor and add a mixed solution of glacial acetic acid / acetic anhydride at a mass-to-liquid ratio of 1g:12ml to the biochar precursor. The volume ratio of glacial acetic acid to acetic anhydride is 1:1. After fully swelling for 40 minutes, add 2% sulfuric acid at a mass-to-liquid ratio of 1:0.8ml to the biochar precursor. Stir and reflux for 6 hours, then filter, wash with deionized water until neutral, and dry in an oven at 65±5℃ to constant weight to obtain acetylated biochar;

[0044] (3) Ferrous sulfate heptahydrate was mixed with water at a mass-liquid ratio of 1 g: 0.5 L, and gum arabic was added while stirring at a speed of 300 rpm. After mixing, acetylated biochar was added, and finally sodium sulfide nonahydrate solution was added at a rate of 2 to 3 drops per second. The sodium sulfide nonahydrate solution was previously mixed with water at a mass-liquid ratio of 1 g: 20 ml with sodium sulfide nonahydrate. After the sodium sulfide nonahydrate solution was added, stirring was continued for 3 hours. The entire process was completed in a nitrogen atmosphere. After stirring, it was allowed to stand for 12 hours and dried to obtain biochar loaded with ferrous sulfide.

[0045] (4) Tin titanium carbide and anhydrous ethanol were mixed at a mass-liquid ratio of 1 g:55 ml and stirred evenly, and then biochar loaded with ferrous sulfide was added. In a nitrogen atmosphere, the mixture was stirred at 40 ° C for 35 min, and then polyethyleneimine was added. The mixture was stirred at 70 ° C for 2.5 h, and then filtered, washed three times with deionized water, and vacuum freeze-dried for 12 h.

[0046] Comparative Example 1

[0047] Specific raw materials were weighed according to Table 1. The difference from Example 3 was that titanium dioxide was used instead of tin titanium carbide. The remaining preparation steps were the same as Example 3.

[0048] Comparative Example 2

[0049] Specific raw materials were weighed according to Table 1. The difference from Example 3 was that tin dioxide was used instead of tin titanium carbide. The remaining preparation steps were the same as Example 3.

[0050] Comparative Example 3

[0051] Specific raw materials were weighed according to Table 1. The difference from Example 3 was that a mixture of tin dioxide and titanium dioxide was used instead of tin titanium carbide, wherein the mass ratio of tin dioxide to titanium dioxide was 2:6. The remaining preparation steps were the same as Example 3.

[0052] Comparative Example 4

[0053] The specific raw materials were weighed according to Table 1. Unlike Example 3, H2O2-oxidized biochar was used instead of acetylated biochar. In step (2), the prepared biochar precursor was mixed with 30% H2O2 at a mass-to-liquid ratio of 5g:40ml. The mixture was reacted in the dark for 8 hours, filtered, and rinsed three times with deionized water. The mixture was dried in an 80°C oven for 24 hours and stored in a sealed bag for later use. This was the H2O2-oxidized biochar. The remaining preparation steps were the same as in Example 3.

[0054] Comparative Example 5

[0055] The specific raw materials were weighed according to Table 1. Unlike Example 3, hydrochloric acid-activated biochar was used instead of acetylated biochar. Step (2) included immersing the prepared biochar precursor in a 1 mol / L HCl solution, thoroughly mixing for 24 hours, and then rinsing three times with deionized water. The biochar was then dried in an 80°C oven for 24 hours and stored in a sealed bag for later use. This provided the hydrochloric acid-activated biochar. The remaining preparation steps were the same as in Example 3.

[0056] Comparative Example 6

[0057] The specific raw materials were weighed according to Table 1. Unlike Example 3, sodium hydroxide-activated biochar was used instead of acetylated biochar. In step (2), the prepared biochar precursor was immersed in a 1 mol / L NaOH solution, mixed thoroughly for 24 hours, and then rinsed three times with deionized water. The biochar was dried in an 80°C oven for 24 hours and stored in a sealed bag for later use. This was sodium hydroxide-activated biochar. The remaining preparation steps were the same as in Example 3.

[0058] Table 1

[0059]

[0060] Performance evaluation

[0061] 10 mg of each of Examples 1 to 3 and Comparative Examples 1 to 5 was weighed into a 100 mL wide-mouth conical flask, and 30 mL of OTC solution with concentrations of 50, 100, 200, 300, and 400 mg / L was added. At pH 3, 0.050 mL of H2O2 was added and the mixture was allowed to stand at room temperature for 3 hours. After the reaction was completed, the OTC content in the filtrate was determined using an ultraviolet spectrophotometer. Each treatment was repeated 3 times. Wherein, OTC removal rate (%): K = (C0-C e ) / C0×100%; where: K(%) is the OTC removal rate; C0(mg / L) is the initial concentration of OTC; C e (mg / L) is the concentration of OTC in the system after the reaction. Specific results are shown in Table 2.

[0062] Effect of Coexisting Ions on OTC Degradation: NaCO solutions and NaCl solutions with ion concentrations of 100, 200, and 400 mg / L were prepared, along with solutions with fulvic acid concentrations of 10, 20, and 40 mg / L. OTC was added to each solution to achieve an OTC concentration of 200 mg / L. 10 mg of each of Example 3, Comparative Example 3, and Comparative Example 4 was weighed into a 100 mL wide-mouthed conical flask, and 30 mL of each mixed solution was added. At pH 2, 0.050 mL of H2O2 was added and the mixture was allowed to stand at room temperature for 2 hours. After completion of the reaction, the mixture was filtered, and the OTC content in the filtrate was measured using a UV spectrophotometer at 354 nm. Each treatment was repeated three times. Specific results are shown in Tables 3 to 5.

[0063] Table 2 Effect of OTC degradation rate

[0064] 50mg / L 100mg / L 200mg / L 300mg / L 400mg / L Example 1 91.12％ 91.36％ 93.45％ 93.28％ 94.35％ Example 2 93.82％ 94.27％ 94.58％ 95.16％ 96.57％ Example 3 95.23％ 95.48％ 96.35％ 97.63％ 97.88％ Comparative Example 1 42.75％ 68.31％ 81.42％ 85.86％ 92.36％ Comparative Example 2 44.26％ 69.74％ 82.33％ 87.18％ 93.13％ Comparative Example 3 61.48％ 76.33％ 85.62％ 90.66％ 93.68％ Comparative Example 4 80.54％ 81.67％ 83.51％ 84.94％ 85.26％ Comparative Example 5 54.85％ 56.92％ 55.33％ 57.62％ 58.61％ Comparative Example 6 71.18％ 72.49％ 74.78％ 75.16％ 77.35％

[0065] Table 3 Effect of Na2CO3 concentration on OTC degradation rate

[0066] / 100mg / L 200mg / L 400mg / L Example 3 96.35％ 92.41％ 86.42％ 73.13％ Comparative Example 3 85.62％ 76.93％ 65.84％ 52.64％ Comparative Example 4 83.51％ 78.67％ 72.58％ 61.76％

[0067] Table 4 Effect of NaCl concentration on OTC degradation rate

[0068] / 100mg / L 200mg / L 400mg / L Example 3 96.35％ 94.72％ 90.37％ 87.75％ Comparative Example 3 85.62％ 81.46％ 73.58％ 65.28％ Comparative Example 4 83.51％ 80.15％ 76.30％ 72.34％

[0069] Table 5 Effect of fulvic acid concentration on OTC degradation rate

[0070] / 100mg / L 200mg / L 400mg / L Example 3 96.35％ 95.18％ 92.32％ 88.39％ Comparative Example 3 85.62％ 83.69％ 81.65％ 75.81％ Comparative Example 4 83.51％ 79.86％ 73.21％ 66.29％

[0071] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A composition for catalytic degradation of oxytetracycline, characterized in that: The composition for catalytic degradation of oxytetracycline is composed of the following raw materials in parts by weight: 5 to 15 parts of acetylated biochar, 15 to 45 parts of ferrous sulfate heptahydrate, 10 to 30 parts of sodium sulfide nonahydrate, 5 to 15 parts of gum arabic, 4 to 8 parts of tin titanium carbide, and 1 to 2 parts of polyethyleneimine; The composition for catalytic degradation of oxytetracycline is prepared by the following steps: (1) The washed and dried chestnut shells were crushed with a crusher and passed through a 40-mesh crusher, and then placed in a tubular furnace under a nitrogen atmosphere and heated at 10°C / min-1 to a set temperature for pyrolysis. After reaching the set temperature, the shells were kept warm for 2.0 to 2.5 hours, and the set temperature was 700 to 750°C. The shells were then cooled to room temperature to obtain a biochar precursor. (2) Take the biochar precursor, add a mixed solution of glacial acetic acid / acetic anhydride at a mass-to-liquid ratio of 1g:10-12ml to the biochar precursor, and the volume ratio of glacial acetic acid to acetic anhydride is 1:

1. After fully swelling for 30-40min, add 2% sulfuric acid at a mass-to-liquid ratio of 1:0.5-0.8ml to the biochar precursor, stir and reflux for 5-6h, then filter, wash with deionized water until neutral, and dry in an oven at 65±5℃ to constant weight to obtain acetylated biochar; (3) Ferrous sulfate heptahydrate was mixed with water at a mass-liquid ratio of 1g:0.5L, and gum arabic was added while stirring at a speed of 200-300rpm. After mixing, acetylated biochar was added, and finally sodium sulfide nonahydrate solution was added at a rate of 2-3 drops per second. The sodium sulfide nonahydrate solution was previously mixed with water at a mass-liquid ratio of 1g:20ml using sodium sulfide nonahydrate. After the sodium sulfide nonahydrate solution was added, stirring was continued for 3h. The whole process was completed in a nitrogen atmosphere. After stirring, it was allowed to stand for 10-12h and dried to obtain biochar loaded with ferrous sulfide. (4) Titanium tin carbide and anhydrous ethanol were mixed at a mass-liquid ratio of 1 g: 50-55 ml and stirred evenly, and then biochar loaded with ferrous sulfide was added. In a nitrogen protective atmosphere, the mixture was stirred at 30°C to 40°C for 30-35 minutes, and then polyethyleneimine was added. The mixture was stirred at 60°C to 70°C for 2-2.5 hours, and then filtered, washed three times with deionized water, and vacuum freeze-dried for 10-12 hours.

2. The composition for catalytic degradation of oxytetracycline according to claim 1, characterized in that The particle size of the tin titanium carbide is 200-300 meshes, and the purity is ≥98%.

3. A method for preparing the composition for catalytic degradation of oxytetracycline according to claim 1, characterized in that: The composition for catalytic degradation of oxytetracycline is prepared by the following steps: (1) The washed and dried chestnut shells were crushed with a crusher and passed through a 40-mesh crusher, and then placed in a tubular furnace under a nitrogen atmosphere and heated at 10°C / min-1 to a set temperature for pyrolysis. After reaching the set temperature, the shells were kept warm for 2.0 to 2.5 hours, and the set temperature was 700 to 750°C. The shells were then cooled to room temperature to obtain a biochar precursor. (2) Take the biochar precursor, add a mixed solution of glacial acetic acid / acetic anhydride at a mass-to-liquid ratio of 1g:10-12ml to the biochar precursor, and the volume ratio of glacial acetic acid to acetic anhydride is 1:

1. After fully swelling for 30-40min, add 2% sulfuric acid at a mass-to-liquid ratio of 1:0.5-0.8ml to the biochar precursor, stir and reflux for 5-6h, then filter, wash with deionized water until neutral, and dry in an oven at 65±5℃ to constant weight to obtain acetylated biochar; (3) Ferrous sulfate heptahydrate was mixed with water at a mass-liquid ratio of 1g:0.5L, and gum arabic was added while stirring at a speed of 200-300rpm. After mixing, acetylated biochar was added, and finally sodium sulfide nonahydrate solution was added at a rate of 2-3 drops per second. The sodium sulfide nonahydrate solution was previously mixed with water at a mass-liquid ratio of 1g:20ml using sodium sulfide nonahydrate. After the sodium sulfide nonahydrate solution was added, stirring was continued for 3h. The whole process was completed in a nitrogen atmosphere. After stirring, it was allowed to stand for 10-12h and dried to obtain biochar loaded with ferrous sulfide. (4) Titanium tin carbide and anhydrous ethanol were mixed at a mass-liquid ratio of 1 g: 50-55 ml and stirred evenly, and then biochar loaded with ferrous sulfide was added. In a nitrogen protective atmosphere, the mixture was stirred at 30°C to 40°C for 30-35 minutes, and then polyethyleneimine was added. The mixture was stirred at 60°C to 70°C for 2-2.5 hours, and then filtered, washed three times with deionized water, and vacuum freeze-dried for 10-12 hours.

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