Preparation of S / N co-doped modified biochar composite material and application of S / N co-doped modified biochar composite material in activating persulfate to degrade and remove antibiotics

Abstract

The invention provides preparation of an S / N co-doped modified biochar composite material and application of the S / N co-doped modified biochar composite material in activated persulfate resource degradation and removal of antibiotics, belongs to the technical field of wastewater treatment, and aims to efficiently degrade and remove antibiotics in wastewater and avoid environmental risks of a metal catalyst at the same time. The method is a green, environment-friendly, economical and efficient water treatment method; the preparation method comprises the following specific steps: S1, mixing and grinding waste crop biomass and metal salt to prepare modified biochar; s2, mixing and grinding the modified charcoal and a sulfur-containing compound; s3, performing high-temperature pyrolysis on the ground mixture to obtain an S / N co-doped modified charcoal composite material, and using the S / N co-doped modified charcoal composite material as a persulfate catalyst to effectively degrade and remove tetracycline in polluted wastewater; the S / N co-doped modified biochar composite material prepared by the invention effectively solves the problem of secondary utilization of waste crops, mainly improves the degradation and removal efficiency of tetracycline and realizes resource conversion of tetracycline.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and in particular relates to the preparation of an S / N co-doped modified biochar composite material and the application of the composite material in activating persulfate to degrade and remove antibiotics. Background Art

[0002] With the progress of industrialization, various chemical products are produced and used in large quantities in modern industries, and the public health and environmental pollution problems caused by some new pollutants are becoming increasingly prominent. In recent years, the large-scale production and use of antibiotics have caused residues to cause pollution in environmental water. Due to the characteristics of large discharge volume, high biological toxicity and poor biodegradability, antibiotic wastewater poses a great threat to human health and ecological safety. Therefore, the development of economical and efficient antibiotic wastewater treatment methods has become a research hotspot in the field of water treatment. At present, a variety of technologies for removing antibiotics from water have been developed, including physical adsorption, electrochemical processes, biodegradation, photocatalysis and persulfate advanced oxidation method. Among them, persulfate advanced oxidation method (PMS) is a method based on peroxymonosulfate (HSO5 - ) is an advanced oxidation technology that activates peroxymonosulfate to produce strong oxidizing species (such as free radicals or non-radical active substances) for the efficient degradation of organic pollutants in water bodies, such as antibiotics, pesticides, dyes, etc. Its core is to activate peroxymonosulfate by physical, chemical or biological means to generate active species with strong oxidizing ability, thereby realizing the resource conversion of pollutants. PMS is considered to be an effective technology for removing antibiotics from contaminated wastewater, and antibiotics can be degraded into small molecular organic acids, CO2, H2O, nitrates and sulfates through free radical oxidation. This process not only achieves the efficient removal of antibiotics, but also has the outstanding advantages of high efficiency and low cost, which has aroused great interest among scientific researchers.

[0003] The widespread use of antibiotics has led to their ubiquitous presence in water bodies, making traditional biological treatment and physical adsorption methods ineffective in degrading these pollutants. Persulfate advanced oxidation technology has become a popular choice for antibiotic degradation due to its high efficiency and wide applicability. Biochar, as a low-cost, sustainable catalyst support, exhibits great potential for antibiotic degradation by activating persulfate to generate highly reactive free radicals. Therefore, heteroatom-doped biochar has been proposed to activate persulfate degradation of antibiotics, thereby achieving efficient antibiotic degradation in wastewater. Heteroatom doping can be categorized as either metal or non-metallic. Commonly used metals include manganese, iron, bismuth, magnesium, potassium, and nickel, while non-metallic elements include nitrogen, sulfur, iodine, phosphorus, and boron. Metal-doped biochar may pose environmental risks, such as overflow, in pollutant removal. Compared to metal doping, non-metallic doping offers the advantages of low cost and environmental friendliness. Research has shown that nitrogen doping can increase the surface functional groups, surface charge, and specific surface area of biochar. Furthermore, introducing sulfur atoms into biochar is a promising modification technique that can enhance its adsorption properties. Biochar co-doped with nitrogen and sulfur atoms is significantly superior to ordinary biochar in activating persulfate to degrade and remove organic pollution, and has great application prospects in the field of water treatment. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a S / N co-doped modified biochar composite material and activating persulfate to degrade and remove antibiotics, which can be used to degrade antibiotics in wastewater while avoiding the environmental risks of metal catalysts, thereby achieving green, environmentally friendly, economical and efficient water treatment.

[0005] The object of the present invention is achieved like this:

[0006] In a first aspect, a method for preparing a S / N co-doped modified biochar composite material is characterized by comprising the following specific steps:

[0007] Step 1: Grind and mix the waste crop biomass and metal salt derivatives in an agate mortar until uniformly mixed. The mixture is placed in a tube furnace, and an inert gas is introduced into the tube furnace. Under the protection of the inert gas, the mixture is pyrolyzed at a temperature of 600°C to 900°C to obtain a modified biochar material.

[0008] Step 2: Mixing and grinding the obtained modified biochar material and the sulfur-containing compound in a certain proportion to obtain a ground mixture;

[0009] Step 3: Place the ground mixture in a tubular furnace, introduce inert gas into the tubular furnace, and perform high-temperature pyrolysis on the mixture under the protection of the inert gas. After the temperature of the tubular furnace is cooled to room temperature, wash the product with dilute hydrochloric acid and distilled water 3 to 5 times, and then dry it at 50°C to 100°C for 10h to 24h to obtain an S / N co-doped modified biochar composite material.

[0010] Furthermore, in step 1, the waste crop biomass is at least one of corn stalks, sunflower stalks, grapefruit peels, and ginkgo leaves.

[0011] Furthermore, in step 1, the metal salt derivative is at least one of anhydrous calcium carbonate, anhydrous sodium carbonate, and anhydrous magnesium carbonate.

[0012] Furthermore, in step 1, the mass ratio of the waste crop biomass to the metal salt derivative is 1-10:1-5; the waste crop biomass and the metal salt derivative are ground and mixed evenly, and the grinding time is 0.3h to 2h.

[0013] Furthermore, in step 2, the sulfur-containing compound is at least one of thioacetamide (CH3CSNH2), thiobenzamide (C6H5CSNH2), thiourea (CS(NH2)2), and phenyl thiocarbamate (NH2CSOC6H5).

[0014] Furthermore, in step 2, the modified biochar material and the sulfur-containing compound are mixed in a mass ratio of 1 to 10:1 to 5; the modified biochar and the sulfur-containing compound are mixed and ground for a grinding time of 0.3 h to 2 h.

[0015] Furthermore, in step 3, the modified biochar and sulfur-containing compounds are pyrolyzed at high temperature in a tubular furnace, the pyrolysis temperature is 500°C to 900°C, the pyrolysis time is 1h to 5h, and the heating rate of the tubular furnace is 5°C / min to 10°C / min.

[0016] In the second aspect, the prepared S / N co-doped modified biochar composite material is used as a catalyst in the activation of persulfate to degrade and remove antibiotics in wastewater, and the specific steps are as follows:

[0017] S / N co-doped modified biochar composite material is added to the contaminated wastewater containing antibiotics. The S / N co-doped modified biochar composite material serves as a catalyst, and an oxidant persulfate solution is added after the adsorption equilibrium is reached.

[0018] Furthermore, the antibiotic in the contaminated wastewater is tetracycline.

[0019] Furthermore, the oxidant persulfate solution is peroxymonosulfate (HSO5 -); the pollutant concentration is 2 mg / L to 100 mg / L, the solution volume is 10 mL to 200 mL, the amount of the oxidant is 20 mg / L to 1000 mg / L, and the amount of the catalyst is 3 mg to 50 mg.

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

[0021] 1. This application uses a simple method of combining mixing, grinding, and one-step pyrolysis to synthesize S / N co-doped modified biochar composite materials. The preparation method is simple and the prepared composite material has high activation performance;

[0022] 2. The S / N co-doped modified biochar composite material of the present invention can be used to activate PMS to degrade and remove tetracycline. The activation effect is relatively significant. The material does not contain metal ions, which can effectively avoid secondary pollution of harmful metals and provide inspiration for the further design of PMS-based waste treatment catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 Flow chart of the preparation of S / N co-doped modified biochar composite material of the present invention;

[0025] Figure 2 FTIR graph prepared in Example 1;

[0026] Figure 3 FTIR graph prepared in Example 2;

[0027] Figure 4 FTIR pattern prepared in Example 3;

[0028] Figure 5 FTIR pattern prepared in Example 4;

[0029] Figure 6 FTIR pattern prepared in Example 5;

[0030] Figure 7 FTIR pattern prepared in Example 6;

[0031] Figure 8 FTIR pattern prepared in Example 7;

[0032] Figure 9 FTIR pattern prepared in Example 8;

[0033] Figure 10 The proportion of tetracycline removal by adsorption and PMS degradation by the catalysts prepared in Examples 1, 2, 3, and 4;

[0034] Figure 11 The ratio of tetracycline removal by adsorption and PMS degradation by the catalysts prepared in Examples 5, 6, 7 and 8. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0036] First, as Figure 1 As shown, the present invention provides a method for preparing a S / N co-doped modified biochar composite material, characterized in that the specific steps are as follows:

[0037] Step 1: Grind and mix the waste crop biomass and metal salt derivatives in an agate mortar until uniformly mixed. The mixture is placed in a tube furnace, and an inert gas is introduced into the tube furnace. Under the protection of the inert gas, the mixture is pyrolyzed at a temperature of 600°C to 900°C to obtain a modified biochar material.

[0038] Step 2: Mixing and grinding the obtained modified biochar material and the sulfur-containing compound in a certain proportion to obtain a ground mixture;

[0039] Step 3: Place the ground mixture in a tubular furnace, introduce inert gas into the tubular furnace, and perform high-temperature pyrolysis on the mixture under the protection of the inert gas. After the temperature of the tubular furnace is cooled to room temperature, wash the product with dilute hydrochloric acid and distilled water 3 to 5 times, and then dry it at 50°C to 100°C for 10h to 24h to obtain an S / N co-doped modified biochar composite material.

[0040] Optionally, in step 1, the waste crop biomass is at least one of corn stalks, sunflower stalks, grapefruit peels, and ginkgo leaves.

[0041] Specifically, waste agricultural biomass is economical, environmentally friendly, and readily available. Furthermore, it is soft and has a significant surface area and pores after high-temperature carbonization. These unique properties determine its superiority in material preparation. Furthermore, this represents another new avenue for utilizing waste agricultural biomass.

[0042] Optionally, in step 1, the metal salt derivative is at least one of anhydrous calcium carbonate, anhydrous sodium carbonate, and anhydrous magnesium carbonate.

[0043] Specifically, in the process of grinding and uniformly mixing waste crop biomass and metal salt derivatives, the metal salt derivatives can act as activators to activate the biomass and regulate the micromorphology of the biomass, and convert it into high-value products through the synergistic effect of physical crushing and chemical catalysis.

[0044] Optionally, in step 1, the inert gas is at least one of nitrogen, helium, argon or a mixed gas.

[0045] Specifically, the core role of inert gas is to provide an oxygen-free environment, prevent oxidation and combustion, and ensure the efficient conversion of biomass into high-purity, structurally stable modified biochar.

[0046] Optionally, in step 1, the mass ratio of the waste crop biomass to the metal salt derivative is 1-10:1-5; the waste crop biomass and the metal salt derivative are ground and mixed evenly, and the grinding time is 0.3h to 2h.

[0047] Optionally, in step 2, the sulfur-containing compound is at least one of thioacetamide (CH3CSNH2), thiobenzamide (C6H5CSNH2), thiourea (CS(NH2)2), and phenyl thiocarbamate (NH2CSOC6H5).

[0048] Specifically, sulfur-containing compounds are used to provide S and N heteroatoms, the purpose of which is to reduce the toxicity of the material and avoid leaching of metal ions into water during the water treatment process, thereby causing secondary pollution of the water body.

[0049] Optionally, in step 2, the modified biochar material and the sulfur-containing compound are mixed in a mass ratio of 1 to 10:1 to 5, which can be determined by parallel experiments; the modified biochar and the sulfur-containing compound are mixed and ground for 0.3 h to 2 h.

[0050] Optionally, in step 3, the modified biochar and sulfur-containing compounds are pyrolyzed at high temperature in a tubular furnace, the pyrolysis temperature is 500°C to 900°C, the pyrolysis time is 1h to 5h, and the heating rate of the tubular furnace is 5°C / min to 10°C / min.

[0051] In the second aspect, the prepared S / N co-doped modified biochar composite material is used as a catalyst in the activation of persulfate to degrade and remove antibiotics from wastewater. The specific method is as follows:

[0052] A S / N co-doped modified biochar composite was added to contaminated wastewater containing antibiotics. The S / N co-doped modified biochar composite served as a catalyst. After adsorption equilibrium was reached, a persulfate solution was added as an oxidant. The persulfate solution was activated by the S / N co-doped modified biochar composite to produce highly active free radicals that degraded the antibiotics in the wastewater. Through free radical oxidation, the antibiotics were degraded into small-molecule organic acids, CO₂, H₂O, nitrates, and sulfates. The products and some intermediates (such as short-chain fatty acids) can be further recycled. This process not only achieves efficient degradation and removal of antibiotics but also enables the resource conversion of the products and some intermediates, improving the economic and environmental sustainability of the system through material design.

[0053] Optionally, the antibiotic in the contaminated wastewater is tetracycline.

[0054] Optionally, the oxidant persulfate solution is peroxymonosulfate (HSO5 - ); the pollutant concentration is 2 mg / L to 100 mg / L, the solution volume is 10 mL to 200 mL, the amount of the oxidant is 20 mg / L to 1000 mg / L, and the amount of the catalyst is 3 mg to 50 mg.

[0055] Alternatively, the antibiotic-contaminated wastewater, the S / N co-doped modified biochar composite, and the oxidant persulfate solution are placed in a magnetic stirrer and stirred at a speed of 200 to 800 rpm. Magnetic stirring allows for better contact between the catalyst and the oxidant persulfate solution. Other instruments with similar functions can achieve this technical effect, so the choice of instrument is not limited.

[0056] The specific embodiments of the present invention are described in detail below:

[0057] Example 1

[0058] Step 1: Mix corn straw and anhydrous calcium carbonate in a mass ratio of 1 to 10: 1 to 5, and grind the mixture in an agate mortar to mix evenly. Place the mixture in a tubular furnace, introduce inert gas (nitrogen, helium, argon or a mixed gas) into the tubular furnace, and perform high-temperature pyrolysis of the mixture at a temperature of 600°C to 900°C under the protection of the inert gas to obtain a modified biochar material.

[0059] Step 2: The obtained modified biochar material and thiourea (CS(NH2)2) are mixed and ground in a mass ratio of 1-10:1-5 for 0.3h-2h to obtain a ground mixture.

[0060] Step 3: Place the ground mixture in a tube furnace, introduce inert gas (nitrogen, helium, argon or mixed gas) into the tube furnace, and perform high-temperature pyrolysis on the mixture under the protection of inert gas. The pyrolysis temperature is 800 ° C, the pyrolysis time is 2 hours, and the heating rate of the tube furnace is 5 ° C / min. After the tube furnace temperature is cooled to room temperature, the product is washed with dilute hydrochloric acid and distilled water 3 to 5 times, and then dried at 50 ° C to 100 ° C for 10 hours to 24 hours to obtain SN@BC 1玉米秸秆 .

[0061] To verify the chemical bond structure of the S / N co-doped modified biochar composite material in this example, the structure of the sample prepared in Example 1 was analyzed and measured.

[0062] from Figure 2 It can be seen that the Fourier transform infrared spectrum of SN@BC 1玉米秸秆 At 3420cm -1 and 928cm -1 The spectral band at 1617 cm can be attributed to NH stretching vibration and CO stretching; -1 、1405cm -1 There is an absorption peak at 2146 cm -1 , 2215cm -1 The absorption peaks are shown at , which may be attributed to C≡C stretching, C≡N stretching and vibration; SN@BC 1玉米秸秆 At 553cm -1 The peaks near α are caused by CS stretching vibration, proving that S element is successfully doped on BC.

[0063] The S / N co-doped modified biochar composite material prepared by the above steps is used as a catalyst to activate persulfate degradation to remove antibiotic pollution in water, wherein the oxidant persulfate solution is potassium hydrogen persulfate; the optimal conditions of the pollutant concentration, the amount of the oxidant, and the amount of the catalyst are satisfied: the pollutant concentration is 20 mg / L, the solution volume is 100 mL, the amount of the oxidant is 400 mg / L, and the amount of the catalyst is 10 mg; the antibiotics in the wastewater are mainly tetracycline.

[0064] Example 2

[0065] Step 1: Mix sunflower straw and anhydrous calcium carbonate in a mass ratio of 1-10:1-5, and grind the mixture in an agate mortar to mix evenly. Place the mixture in a tubular furnace, introduce inert gas (nitrogen, helium, argon or a mixed gas) into the tubular furnace, and perform high-temperature pyrolysis of the mixture at a temperature of 600°C to 900°C under the protection of the inert gas to obtain a modified biochar material.

[0066] Step 2: The obtained modified biochar material and thiourea (CS(NH2)2) are mixed and ground in a mass ratio of 1-10:1-5 for 0.3h-2h to obtain a ground mixture.

[0067] Step 3: Place the ground mixture in a tube furnace, introduce inert gas (nitrogen, helium, argon or mixed gas) into the tube furnace, and perform high-temperature pyrolysis on the mixture under the protection of inert gas. The pyrolysis temperature is 800 ° C, the pyrolysis time is 2 hours, and the heating rate of the tube furnace is 5 ° C / min. After the tube furnace temperature is cooled to room temperature, the product is washed with dilute hydrochloric acid and distilled water 3 to 5 times, and then dried at 50 ° C to 100 ° C for 10 hours to 24 hours to obtain SN@BC 1向日葵秸秆 .

[0068] To verify the chemical bond structure of the S / N co-doped modified biochar composite material in this example, the structure of the sample prepared in Example 2 was analyzed and measured.

[0069] from Figure 3 It can be seen that the Fourier transform infrared spectrum of SN@BC 1向日葵秸秆 At 3426cm -1 and 940cm -1 The spectral band at 1623 cm can be attributed to NH stretching vibration and CO stretching; -1 、1412cm -1 There is an absorption peak at 2153 cm, which may be attributed to C=C stretching vibration and COO- stretching vibration. -1 , 2220cm -1 The absorption peak is shown at , which may be attributed to C≡C stretching, C≡N stretching and vibration, thus proving the successful doping of N element; SN@BC 1向日葵秸秆 At 561cm -1 The peaks near α are caused by CS stretching vibration, proving that S element is successfully doped on BC.

[0070] The S / N co-doped modified biochar composite material prepared by the above steps is used as a catalyst to activate persulfate degradation to remove antibiotic pollution in water, wherein the oxidant persulfate solution is potassium hydrogen persulfate; the optimal conditions of the pollutant concentration, the amount of the oxidant, and the amount of the catalyst are satisfied: the pollutant concentration is 20 mg / L, the solution volume is 100 mL, the amount of the oxidant is 400 mg / L, and the amount of the catalyst is 10 mg; the antibiotics in the wastewater are mainly tetracycline.

[0071] Example 3

[0072] Step 1: Mix grapefruit peel and anhydrous calcium carbonate in a mass ratio of 1-10:1-5, and place the mixture in an agate mortar to grind and mix evenly. Place the mixture in a tubular furnace, introduce inert gas (nitrogen, helium, argon or a mixed gas) into the tubular furnace, and perform high-temperature pyrolysis of the mixture at a temperature of 600°C to 900°C under the protection of the inert gas to obtain a modified biochar material.

[0073] Step 2: The obtained modified biochar material and thiourea (CS(NH2)2) are mixed and ground in a mass ratio of 1-10:1-5 for 0.3h-2h to obtain a ground mixture.

[0074] Step 3: Place the ground mixture in a tube furnace, introduce inert gas (nitrogen, helium, argon or mixed gas) into the tube furnace, and perform high-temperature pyrolysis on the mixture under the protection of inert gas. The pyrolysis temperature is 800 ° C, the pyrolysis time is 2 hours, and the heating rate of the tube furnace is 5 ° C / min. After the tube furnace temperature is cooled to room temperature, the product is washed with dilute hydrochloric acid and distilled water 3 to 5 times, and then dried at 50 ° C to 100 ° C for 10 hours to 24 hours to obtain SN@BC 1柚子皮 .

[0075] To verify the chemical bond structure of the S / N co-doped modified biochar composite material in this example, the structure of the sample prepared in Example 3 was analyzed and measured.

[0076] from Figure 4 It can be seen that the Fourier transform infrared spectrum of SN@BC 1柚子皮 At 3426cm -1 and 940cm -1 The spectral band at 1623 cm can be attributed to NH stretching vibration and CO stretching; -1 、1412cm -1 The absorption peak is shown at , which may be attributed to SN@BC 1柚子皮 C=C stretching vibration, COO– stretching vibration; In addition, at 2153cm -1 , 2220cm-1 The absorption peak is shown at 561cm, which may be attributed to C≡C stretching, C≡N stretching and vibration, which also proves the successful doping of N element; -1 The peaks near α are caused by CS stretching vibration, proving that S element is successfully doped on BC.

[0077] At the same time by Figure 1 Figure 2 By comparison, the peak intensity of grapefruit peel biochar is better.

[0078] The S / N co-doped modified biochar composite material prepared by the above steps is used as a catalyst to activate persulfate degradation to remove antibiotic pollution in water, wherein the oxidant persulfate solution is potassium hydrogen persulfate; the optimal conditions of the pollutant concentration, the amount of the oxidant, and the amount of the catalyst are satisfied: the pollutant concentration is 20 mg / L, the solution volume is 100 mL, the amount of the oxidant is 400 mg / L, and the amount of the catalyst is 10 mg; the antibiotics in the wastewater are mainly tetracycline.

[0079] Example 4

[0080] Step 1: Mix ginkgo leaves and anhydrous calcium carbonate in a mass ratio of 1 to 10: 1 to 5, and grind the mixture in an agate mortar to mix evenly. Place the mixture in a tubular furnace, introduce inert gas (nitrogen, helium, argon or a mixed gas) into the tubular furnace, and perform high-temperature pyrolysis of the mixture at a temperature of 600°C to 900°C under the protection of the inert gas to obtain a modified biochar material.

[0081] Step 2: The obtained modified biochar material and thiourea (CS(NH2)2) are mixed and ground in a mass ratio of 1-10:1-5 for 0.3h-2h to obtain a ground mixture.

[0082] Step 3: Place the ground mixture in a tube furnace, introduce inert gas (nitrogen, helium, argon or mixed gas) into the tube furnace, and perform high-temperature pyrolysis on the mixture under the protection of inert gas. The pyrolysis temperature is 800 ° C, the pyrolysis time is 2 hours, and the heating rate of the tube furnace is 5 ° C / min. After the tube furnace temperature is cooled to room temperature, the product is washed with dilute hydrochloric acid and distilled water 3 to 5 times, and then dried at 50 ° C to 100 ° C for 10 hours to 24 hours to obtain SN@BC 1银杏树叶 .

[0083] To verify the structure of the S / N co-doped modified biochar composite material in this example, the structure of the sample prepared in Example 4 was analyzed and measured.

[0084] from Figure 5It can be seen that the Fourier transform infrared spectrum of SN@BC 1银杏树叶 940cm -1 The spectral band at 1623 cm is attributable to CO stretching; -1 、1412cm -1 There is an absorption peak at 2153 cm -1 , 2220cm -1 The absorption peak is shown at , which may be attributed to C≡C stretching, C≡N stretching and vibration, thus proving the successful doping of N element; SN@BC 1银杏树叶 At 561cm -1 The peaks near α are caused by CS stretching vibration, proving that S element is successfully doped on BC.

[0085] The S / N co-doped modified biochar composite material prepared by the above steps is used as a catalyst to activate persulfate degradation to remove antibiotic pollution in water, wherein the oxidant persulfate solution is potassium hydrogen persulfate; the optimal conditions of the pollutant concentration, the amount of the oxidant, and the amount of the catalyst are satisfied: the pollutant concentration is 20 mg / L, the solution volume is 100 mL, the amount of the oxidant is 400 mg / L, and the amount of the catalyst is 10 mg; the antibiotics in the wastewater are mainly tetracycline.

[0086] Example 5

[0087] Step 1: Mix corn straw and anhydrous sodium carbonate in a mass ratio of 1 to 10: 1 to 5, and grind the mixture in an agate mortar to mix evenly. Place the mixture in a tubular furnace, introduce inert gas (nitrogen, helium, argon or a mixed gas) into the tubular furnace, and perform high-temperature pyrolysis of the mixture at a temperature of 600°C to 900°C under the protection of the inert gas to obtain a modified biochar material.

[0088] Step 2: The obtained modified biochar material and thiourea (CS(NH2)2) are mixed and ground in a mass ratio of 1-10:1-5 for 0.3h-2h to obtain a ground mixture.

[0089] Step 3: Place the ground mixture in a tube furnace, introduce inert gas (nitrogen, helium, argon or mixed gas) into the tube furnace, and perform high-temperature pyrolysis on the mixture under the protection of inert gas. The pyrolysis temperature is 800 ° C, the pyrolysis time is 2 hours, and the heating rate of the tube furnace is 5 ° C / min. After the tube furnace temperature is cooled to room temperature, the product is washed with dilute hydrochloric acid and distilled water 3 to 5 times, and then dried at 50 ° C to 100 ° C for 10 hours to 24 hours to obtain SN@BC 2玉米秸秆 .

[0090] To verify the chemical bond structure of the S / N co-doped modified biochar composite material in this example, the structure of the sample prepared in Example 5 was analyzed and measured.

[0091] from Figure 6 It can be seen that the Fourier transform infrared spectrum of SN@BC 2玉米秸秆 At 3694cm -1 The spectral band at 2530 cm-1 can be attributed to OH stretching vibration; -1 The absorption peak at 1781 cm-1 is likely due to SH stretching vibration, proving that S element is successfully doped on BC. -1 、1416cm -1 The absorption peaks are shown at , which may be attributed to C=O stretching, CH stretching and vibration; SN@BC 2玉米秸秆 At 824cm -1 and 717cm -1 The peaks nearby are caused by C-H stretching vibrations.

[0092] The S / N co-doped modified biochar composite material prepared by the above steps is used as a catalyst to activate persulfate degradation to remove antibiotic pollution in water, wherein the oxidant persulfate solution is potassium hydrogen persulfate; the optimal conditions of the pollutant concentration, the amount of the oxidant, and the amount of the catalyst are satisfied: the pollutant concentration is 20 mg / L, the solution volume is 100 mL, the amount of the oxidant is 400 mg / L, and the amount of the catalyst is 10 mg; the antibiotics in the wastewater are mainly tetracycline.

[0093] Example 6

[0094] Step 1: Mix sunflower straw and anhydrous sodium carbonate in a mass ratio of 1-10:1-5, and grind the mixture in an agate mortar to mix evenly. Place the mixture in a tubular furnace, introduce inert gas (nitrogen, helium, argon or mixed gas) into the tubular furnace, and perform high-temperature pyrolysis of the mixture at a temperature of 600°C to 900°C under the protection of the inert gas to obtain modified biochar material.

[0095] Step 2: The obtained modified biochar material and thiourea (CS(NH2)2) are mixed and ground in a mass ratio of 1-10:1-5 for 0.3h-2h to obtain a ground mixture.

[0096] Step 3: Place the ground mixture in a tube furnace, introduce inert gas (nitrogen, helium, argon or mixed gas) into the tube furnace, and perform high-temperature pyrolysis on the mixture under the protection of inert gas. The pyrolysis temperature is 800 ° C, the pyrolysis time is 2 hours, and the heating rate of the tube furnace is 5 ° C / min. After the tube furnace temperature is cooled to room temperature, the product is washed with dilute hydrochloric acid and distilled water 3 to 5 times, and then dried at 50 ° C to 100 ° C for 10 hours to 24 hours to obtain SN@BC 2向日葵秸秆 .

[0097] To verify the chemical bond structure of the S / N co-doped modified biochar composite material in this example, the structure of the sample prepared in Example 6 was analyzed and measured.

[0098] from Figure 7 It can be seen that the Fourier transform infrared spectrum of SN@BC 2向日葵秸秆 At 3694cm -1 The spectral band at 2530 cm-1 can be attributed to OH stretching vibration; -1 The absorption peak at 1781 cm-1 is likely due to SH stretching vibration, proving that S element is successfully doped on BC. -1 、1416cm -1 The absorption peaks are shown at , which may be attributed to C=O stretching, CH stretching and vibration; SN@BC 2向日葵秸秆 At 824cm -1 and 717cm -1 The peaks nearby are caused by C-H stretching vibrations.

[0099] The S / N co-doped modified biochar composite prepared in the above steps is used as a catalyst to activate persulfate degradation to remove antibiotic contamination in water. The persulfate solution used as the oxidant is potassium persulfate. The optimal conditions for pollutant concentration, oxidant dosage, and catalyst dosage are: a pollutant concentration of 20 mg / L, a solution volume of 100 mL, an oxidant dosage of 400 mg / L, and a catalyst dosage of 10 mg. The antibiotics in the wastewater are primarily tetracycline.

[0100] Example 7

[0101] Step 1: Mix grapefruit peel and anhydrous sodium carbonate in a mass ratio of 1-10:1-5, and place the mixture in an agate mortar to grind and mix evenly. Place the mixture in a tubular furnace, introduce inert gas (nitrogen, helium, argon or a mixed gas) into the tubular furnace, and perform high-temperature pyrolysis of the mixture at a temperature of 600°C to 900°C under the protection of the inert gas to obtain a modified biochar material.

[0102] Step 2: The obtained modified biochar material and thiourea (CS(NH2)2) are mixed and ground in a mass ratio of 1-10:1-5 for 0.3h-2h to obtain a ground mixture.

[0103] Step 3: Place the ground mixture in a tube furnace, introduce inert gas (nitrogen, helium, argon or mixed gas) into the tube furnace, and perform high-temperature pyrolysis on the mixture under the protection of inert gas. The pyrolysis temperature is 800 ° C, the pyrolysis time is 2 hours, and the heating rate of the tube furnace is 5 ° C / min. After the tube furnace temperature is cooled to room temperature, the product is washed with dilute hydrochloric acid and distilled water 3 to 5 times, and then dried at 50 ° C to 100 ° C for 10 hours to 24 hours to obtain SN@BC 2柚子皮 .

[0104] To verify the chemical bond structure of the S / N co-doped modified biochar composite material in this example, the structure of the sample prepared in Example 7 was analyzed and measured.

[0105] from Figure 8 It can be seen that the Fourier transform infrared spectrum of SN@BC 2柚子皮 At 1781cm -1 、1416cm -1 There is an absorption peak at 2530 cm, which may be attributed to C=O stretching, CH stretching and vibration; -1 The absorption peak is shown at , which may be attributed to SH stretching vibration, proving that S element is successfully doped on BC; In addition, SN@BC 2柚子皮 At 824cm -1 and 717cm -1 The peaks nearby are caused by C-H stretching vibrations.

[0106] The S / N co-doped modified biochar composite prepared in the above steps is used as a catalyst to activate persulfate degradation to remove antibiotic contamination in water. The persulfate solution used as the oxidant is potassium persulfate. The optimal conditions for pollutant concentration, oxidant dosage, and catalyst dosage are: a pollutant concentration of 20 mg / L, a solution volume of 100 mL, an oxidant dosage of 400 mg / L, and a catalyst dosage of 10 mg. The antibiotics in the wastewater are primarily tetracycline.

[0107] Example 8

[0108] Step 1: Mix ginkgo leaves and anhydrous sodium carbonate in a mass ratio of 1 to 10: 1 to 5, and grind the mixture in an agate mortar to mix evenly. Place the mixture in a tubular furnace, introduce inert gas (nitrogen, helium, argon or a mixed gas) into the tubular furnace, and perform high-temperature pyrolysis of the mixture at a temperature of 600°C to 900°C under the protection of the inert gas to obtain a modified biochar material.

[0109] Step 2: The obtained modified biochar material and thiourea (CS(NH2)2) are mixed and ground in a mass ratio of 1-10:1-5 for 0.3h-2h to obtain a ground mixture.

[0110] Step 3: Place the ground mixture in a tube furnace, introduce inert gas (nitrogen, helium, argon or mixed gas) into the tube furnace, and perform high-temperature pyrolysis on the mixture under the protection of inert gas. The pyrolysis temperature is 800 ° C, the pyrolysis time is 2 hours, and the heating rate of the tube furnace is 5 ° C / min. After the tube furnace temperature is cooled to room temperature, the product is washed with dilute hydrochloric acid and distilled water 3 to 5 times, and then dried at 50 ° C to 100 ° C for 10 hours to 24 hours to obtain SN@BC 2银杏树叶 .

[0111] To verify the chemical bond structure of the S / N co-doped modified biochar composite material in this example, the structure of the sample prepared in Example 8 was analyzed and measured.

[0112] from Figure 9 It can be seen that the Fourier transform infrared spectrum of SN@BC 2银杏树叶 At 3694cm -1 The spectral band at 2530 cm-1 can be attributed to OH stretching vibration; -1 The absorption peak at 1781 cm-1 is likely due to SH stretching vibration, proving that S element is successfully doped on BC. -1 、1416cm -1 The absorption peaks are shown at , which may be attributed to C=O stretching, CH stretching and vibration; SN@BC 2银杏树叶 At 824cm -1 and 717cm -1 The peaks nearby are caused by C-H stretching vibrations.

[0113] The S / N co-doped modified biochar composite material prepared by the above steps is used as a catalyst to activate persulfate degradation to remove antibiotic pollution in water, wherein the oxidant persulfate solution is potassium hydrogen persulfate; the optimal conditions of the pollutant concentration, the amount of the oxidant, and the amount of the catalyst are satisfied: the pollutant concentration is 20 mg / L, the solution volume is 100 mL, the amount of the oxidant is 400 mg / L, and the amount of the catalyst is 10 mg; the antibiotics in the wastewater are mainly tetracycline.

[0114] Figure 10 The ratio of tetracycline removal by adsorption and PMS degradation by the catalysts prepared in Examples 1, 2, 3, and 4 is: Figure 11 The adsorption removal of tetracycline and the proportion of PMS degradation removal by the catalysts prepared in Examples 5, 6, 7, and 8; the four agricultural waste biomasses all showed high-efficiency adsorption performance after modification, and their adsorption removal rates were Figure 10 As shown, 34.3%, 30.1%, 21%, 28.6% and Figure 11 The results show that the four modified materials all have high specific surface areas and pores, which can successfully adsorb tetracycline molecules onto the surface of the materials, thereby enhancing the catalytic oxidation degradation efficiency after the subsequent addition of persulfate. After the introduction of S and N heteroatoms, the degradation efficiency continues to increase because the S and N heteroatoms on the surface of the materials provide sufficient active sites for the advanced oxidation of persulfate, thereby further improving the degradation removal rate.

[0115] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a S / N co-doped modified biochar composite material, characterized in that: The specific steps are as follows: Step 1: Grind and mix the waste crop biomass and metal salt derivatives in an agate mortar until uniformly mixed. The mixture is placed in a tube furnace, and an inert gas is introduced into the tube furnace. Under the protection of the inert gas, the mixture is pyrolyzed at a temperature of 600°C to 900°C to obtain a modified biochar material. Step 2: Mixing and grinding the obtained modified biochar material and the sulfur-containing compound in a certain proportion to obtain a ground mixture; Step 3: Place the ground mixture in a tubular furnace, introduce inert gas into the tubular furnace, and perform high-temperature pyrolysis on the mixture under the protection of the inert gas. After the temperature of the tubular furnace is cooled to room temperature, wash the product with dilute hydrochloric acid and distilled water 3 to 5 times, and then dry it at 50°C to 100°C for 10h to 24h to obtain an S / N co-doped modified biochar composite material.

2. The method for preparing a S / N co-doped modified biochar composite material according to claim 1, characterized in that: In step 1, the waste crop biomass is at least one of corn stalks, sunflower stalks, grapefruit peels, and ginkgo leaves.

3. The method for preparing a S / N co-doped modified biochar composite material according to claim 1, characterized in that: In step 1, the metal salt derivative is at least one of anhydrous calcium carbonate, anhydrous sodium carbonate, and anhydrous magnesium carbonate.

4. The method for preparing a S / N co-doped modified biochar composite material according to claim 1, characterized in that: In step 1, the mass ratio of the waste crop biomass to the metal salt derivative is 1-10:1-5; the waste crop biomass and the metal salt derivative are ground and mixed evenly, and the grinding time is 0.3h-2h.

5. The method for preparing a S / N co-doped modified biochar composite material according to claim 1, characterized in that: In step 2, the sulfur-containing compound is at least one of thioacetamide (CH3CSNH2), thiobenzamide (C6H5CSNH2), thiourea (CS(NH2)2), and phenylthiocarbamate (NH2CSOC6H5).

6. The method for preparing a S / N co-doped modified biochar composite material according to claim 1, characterized in that: In step 2, the modified biochar material and the sulfur-containing compound are mixed in a mass ratio of 1 to 10:1 to 5; the modified biochar and the sulfur-containing compound are mixed and ground for 0.3 h to 2 h.

7. The method for preparing a S / N co-doped modified biochar composite material according to claim 1, characterized in that: In step 3, the modified biochar and sulfur-containing compounds are pyrolyzed at high temperature in a tubular furnace, the pyrolysis temperature is 500°C to 900°C, the pyrolysis time is 1h to 5h, and the heating rate of the tubular furnace is 5°C / min to 10°C / min.

8. Use of the S / N co-doped modified biochar composite material prepared as claimed in claim 1 as a catalyst for the activation of persulfate to degrade and remove antibiotics from wastewater, the specific method being as follows: S / N co-doped modified biochar composite material is added to the contaminated wastewater containing antibiotics. The S / N co-doped modified biochar composite material serves as a catalyst, and an oxidant persulfate solution is added after the adsorption equilibrium is reached.

9. The use of degradation and removal of antibiotics in wastewater according to claim 8, characterized in that: The antibiotic in the contaminated wastewater is tetracycline.

10. The use of degradation and removal of antibiotics in wastewater according to claim 8, characterized in that: The oxidant persulfate solution is persulfate (HSO5 - ); the pollutant concentration is 2 mg / L to 100 mg / L, the solution volume is 10 mL to 200 mL, the amount of the oxidant is 20 mg / L to 1000 mg / L, and the amount of the catalyst is 3 mg to 50 mg.

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