A method for preparing carbon materials from agricultural and forestry waste resources and its use

Abstract

The present invention provides a method for preparing carbon materials by recycling agricultural and forestry waste and its use. The method comprises the following steps: (1) crushing agricultural and forestry waste to obtain powder; (2) carbonizing the powder to obtain biochar; and (3) calcining the biochar to obtain the carbon material. The method for preparing carbon materials provided by the present invention has a simple process, does not use any chemical reagents, is environmentally friendly, and has low cost. The carbon material prepared in this way can produce singlet oxygen under conditions without energy input, light, or oxidant addition, and can be widely used in the field of water treatment containing organic pollutants, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of resource treatment of organic solid waste, and specifically relates to a method for preparing carbon materials by resource treatment of agricultural and forestry wastes and its application. Background Art

[0002] CN113277492A discloses a method for preparing potassium humate and biochar from agricultural and forestry waste. After crushing and screening the agricultural and forestry waste, potassium hydroxide and potassium ferrate solution are added and stirred evenly to obtain a mixture. The mixture is then roasted under vacuum conditions. After the roasting treatment, it is immediately poured into water for quenching, and then solid-liquid separation is performed to obtain potassium humate solution and biochar. This method requires the use of chemicals such as potassium hydroxide and potassium ferrate as raw materials, which has high raw material costs and is not environmentally friendly. At the same time, it also needs to be roasted under vacuum conditions, which requires high preparation equipment and high process costs, making it difficult to apply on a large scale in industry. CN103611497B discloses a method for preparing biochar with high nitrogen and phosphorus adsorption properties from agricultural and forestry waste resources. Using agricultural and forestry waste corn straw, pine wood, and Jerusalem artichoke straw as raw materials, the catalytic properties of light rare earth elements such as lanthanum chloride, cerium chloride, and neodymium chloride are utilized, and pyrolysis is carried out with nitrogen as a protector to prepare biochar with high nitrogen and phosphorus adsorption properties. This method utilizes a wide range of raw materials and employs a low-cost rare earth catalyst. The resulting biochar has a large specific surface area, rich functional groups, negative charge, and high charge density, making it suitable as an adsorbent for aqueous systems to remove various polluting inorganic ions or organic matter. The resulting biochar has a rapid nitrogen and phosphorus adsorption rate and a high adsorption capacity. However, this method requires doping with light rare earth elements, which results in high raw material costs and hinders its widespread application in the treatment of agricultural and forestry waste. CN114570331A discloses a method for preparing nitrogen-doped porous nanobiochar functional materials and their applications. This method involves drying and grinding apple leaves into a powder. The powder is then mixed with KOH or NaOH, and heated to 400°C at a rate of 3-5°C / min under an inert gas or N2 atmosphere for 2 hours to achieve full carbonization. The temperature is then raised to 500-700°C at the same rate and held for 2-3 hours. The carbonized sample reacts with KOH or NaOH at high temperature to produce nitrogen-doped porous nanobiochar. This nano-biochar functional material has a large specific surface area, abundant surface functional groups, and a nanoscale 3D porous sheet structure. It can adsorb and activate persulfate to synergistically remove tetracycline. This process requires chemicals such as KOH or NaOH as raw materials, which are costly and environmentally unfriendly. Furthermore, the addition of persulfate to degrade the antibiotic poses a risk of secondary contamination, limiting its application in organic pollution control.

[0003] Therefore, it is of great significance to provide a technology for resource processing of agricultural and forestry wastes that is simple in process, environmentally friendly and low in cost. Summary of the Invention

[0004] In response to the shortcomings of the prior art, the present invention aims to provide a method for preparing carbon materials from agricultural and forestry waste resources and their use. The method for preparing carbon materials provided by the present invention is simple, does not use any chemical reagents, is environmentally friendly, and is low-cost. The carbon materials prepared in this way can produce singlet oxygen without energy input, light, or the addition of oxidants, and can be widely used in the field of water treatment containing organic pollutants, with broad application prospects.

[0005] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for preparing carbon materials from agricultural and forestry waste resources, the method comprising the following steps:

[0007] (1) Grinding agricultural and forestry waste to obtain powder;

[0008] (2) carbonizing the powder to obtain biochar;

[0009] (3) calcining the biochar to obtain the carbon material.

[0010] In the present invention, agricultural and forestry waste is pulverized to produce a powder, which facilitates subsequent carbonization to form biochar. The resulting biochar is then calcined to produce a carbon material containing carbon vacancies. This carbon material, with a certain number of carbon vacancies, exhibits strong catalytic activity in converting oxygen molecules into superoxide radicals. Electrons accumulated in the carbon vacancies can convert superoxide radicals into singlet oxygen. Compared to existing technologies, the preparation method provided by the present invention does not require any special chemical treatment of the raw materials. The resulting carbon material can produce singlet oxygen without energy input, light exposure, or the addition of oxidants, and exhibits a strong oxidizing effect.

[0011] The present invention does not specifically limit the method of pulverizing in step (1). For example, methods such as ball milling, grinding or crushing with a crusher can be used.

[0012] As a preferred technical solution of the present invention, the agricultural and forestry waste in step (1) includes any one of dichotoma, bamboo, rice straw, wheat straw or corn straw, or a combination of at least two of them, preferably dichotoma.

[0013] It should be noted that Dicranopteris dichotoma is a perennial evergreen fern plant under the family Lipiaceae and genus Dicranopteris, which can be used for ornamental purposes. It is a fern plant that commonly grows in tropical and subtropical red soil hills and barren slopes and forest edges. Dicranopteris dichotoma plants are drought-resistant and barren-resistant, with underground stems crisscrossing and penetrating more than 3 meters into the soil layer, and can be cultivated to control soil erosion.

[0014] Preferably, the average particle size of the powder in step (1) is 80-300 mesh, for example, it can be 80 mesh, 90 mesh, 100 mesh, 150 mesh, 200 mesh, 250 mesh or 300 mesh, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0015] As a preferred technical solution of the present invention, the agricultural and forestry waste is dried before being crushed in step (1).

[0016] Preferably, the temperature of the drying treatment is 105-150°C, for example, it can be 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] The present invention can promote the dehydration of agricultural and forestry wastes by controlling the drying temperature within a specific range, while preventing the agricultural and forestry wastes from being oxidized during the drying process.

[0018] Preferably, the drying time is 24-48 hours, for example, it can be 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours, 36 hours, 38 hours, 40 hours, 42 hours, 44 hours, 46 hours or 48 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] As a preferred technical solution of the present invention, the carbonization in step (2) is carried out in a protective atmosphere.

[0020] Preferably, the gas in the protective atmosphere includes any one of nitrogen, carbon dioxide or an inert gas, or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of nitrogen and carbon dioxide, a combination of carbon dioxide and an inert gas, or a combination of nitrogen and an inert gas, etc.

[0021] Preferably, the inert gas comprises argon.

[0022] As a preferred technical solution of the present invention, the carbonization temperature in step (2) is 400-800°C, for example, it can be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C, preferably 600-650°C.

[0023] In the present invention, if the carbonization temperature is too high, the pore structure of the carbon material will collapse, and the total pore volume and specific surface area will be small; if the carbonization temperature is too low, the carbon material will not be able to effectively form a pore structure, and the total pore volume and specific surface area will also be small.

[0024] Preferably, the carbonization time in step (2) is 1-5 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h or 5 h, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] Preferably, the heating rate of the carbonization in step (2) is 5-15°C / min, for example, it can be 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min or 15°C / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] As a preferred technical solution of the present invention, the calcination in step (3) is carried out in air.

[0027] Preferably, the calcination temperature is 800-1000°C, for example, 800°C, 850°C, 900°C, 950°C or 1000°C, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] In the present invention, if the calcination temperature is too low, the carbon material cannot effectively form carbon vacancies, which is not conducive to the generation of singlet oxygen and will lead to a low antibiotic removal rate; if the calcination temperature is too high, the carbon material is easily burned into carbon fragments, which is not conducive to the generation of singlet oxygen and will lead to a decrease in the antibiotic removal rate.

[0029] Preferably, the calcination time is 1-3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] In the present invention, if the calcination time is too long, the carbon material is easily burned into carbon fragments, which is not conducive to the generation of singlet oxygen; if the calcination time is too short, the carbon material cannot effectively form carbon vacancies, which is not conducive to the generation of singlet oxygen.

[0031] Preferably, the heating rate of the calcination is 5-15°C / min, for example, it can be 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min or 15°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] As a preferred technical solution of the present invention, the method comprises the following steps:

[0033] (1) Drying the Dicranopteris dichotoma at 105-150°C for 24-48 hours, and then crushing the powder to obtain a powder with an average particle size of 80-300 mesh;

[0034] (2) heating the powder at a rate of 5-15°C / min in a protective atmosphere and carbonizing at 400-800°C for 1-5 hours to obtain biochar;

[0035] (3) The biochar is heated at a rate of 5-15°C / min under air conditions, and then calcined at 800-1000°C for 1-3 hours to obtain a carbon material.

[0036] In a second aspect, the present invention provides a carbon material, which is prepared by the method described in the first aspect.

[0037] The carbon material prepared by resource utilization of agricultural and forestry waste provided by the present invention has a certain number of carbon vacancies, so it has strong activity. The electrons accumulated on the carbon vacancies can combine with oxygen molecules to produce oxygen active free radicals, and finally generate singlet oxygen. It can be widely used in the field of water treatment containing organic pollutants and has broad application prospects.

[0038] Preferably, the specific surface area of ​​the carbon material is 300-800m 2 / g, for example, it can be 300m 2 / g, 400m 2 / g、500m 2 / g、600m 2 / g、700m 2 / g or 800m 2 / g, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, the carbon material has a porous structure.

[0040] Preferably, the total pore volume of the carbon material is 40-60 cm 3 / g, for example, it can be 40cm 3 / g, 45cm 3 / g, 50cm 3 / g, 55cm 3 / g or 60cm 3 / g, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0041] Preferably, the average pore size of the carbon material is 1.5-2.5 nm, for example, 1.5 nm, 1.7 nm, 1.9 nm, 2.1 nm, 2.3 nm or 2.5 nm, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] In a third aspect, the present invention provides a use of the carbon material according to the second aspect, wherein the carbon material is used in the field of water treatment containing organic matter.

[0043] The carbon material prepared by recycling agricultural and forestry waste provided by the present invention can generate singlet oxygen, thereby degrading and removing organic pollutants in water; compared with the methods for treating sulfamethoxazole in the prior art such as CN115254152A, the carbon material provided by the present invention does not contain metal, has no risk of metal precipitation, and can degrade and remove sulfamethoxazole without adding any oxidant, thus having broad application prospects and high application value.

[0044] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) The method for preparing carbon materials from agricultural and forestry waste resources provided by the present invention is simple to operate, uses a wide range of raw materials, is low-cost, and can be industrialized. Furthermore, the method provided by the present invention solves the problem of agricultural and forestry waste disposal and reduces the waste of biomass resources. It is an efficient, ecological, and environmentally friendly agricultural and forestry waste treatment technology with broad application prospects.

[0047] (2) The carbon material prepared by the method provided by the present invention can generate singlet oxygen under the conditions of no energy input, no light, and no oxidant addition, and can be used to degrade and remove sulfamethoxazole in water. The degradation removal rate of sulfamethoxazole can reach more than 85%, with good oxidative degradation effect. At the same time, the carbon material has good acid and alkali resistance and anti-ion interference. In the range of pH = 3-10, and in the presence of Na 2+ Mg 2+ , K + , Ca 2+ 、Cl - 、NO3 - 、SO4 2- 、HSO3 - 、HPO4 2- and HCO3 2- When at least one of the anions and cations is present, it still has high activity.

[0048] (3) The carbon material prepared by the method provided by the present invention can be used in the field of water treatment containing organic pollutants, and has broad application prospects and high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is an SEM image of the carbon material prepared in Example 1 of the present invention.

[0050] Figure 2 This is the EPR test result diagram of the carbon material prepared in Example 1 of the present invention.

[0051] Figure 3 This is a graph showing the concentration ratio results of the experiment of oxidative removal of sulfamethoxazole using the carbon material prepared in Example 1 of the present invention.

[0052] Figure 4 This is a schematic diagram of the results of a quencher experiment on the carbon material prepared in Example 1 of the present invention.

[0053] Figure 5 Schematic diagram of the results of common cation anti-interference experiments on the carbon material prepared in Example 1 of the present invention.

[0054] Figure 6 Schematic diagram of the results of common anion anti-interference experiments on the carbon material prepared in Example 1 of the present invention.

[0055] Figure 7 Schematic diagram of the experimental results of removing sulfamethoxazole under different pH conditions using the carbon material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0056] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0057] Example 1

[0058] This embodiment provides a method for preparing carbon materials from agricultural and forestry waste resources, the method comprising the following steps:

[0059] (1) Dry the Dicranopteris dichotoma at 120°C for 24 h and then grind it by ball milling to obtain a powder with an average particle size of 200 mesh;

[0060] (2) heating the powder in a tube furnace under an argon atmosphere at a rate of 5°C / min and carbonizing at 600°C for 3 hours to obtain biochar;

[0061] (3) The biochar was heated in a muffle furnace under air conditions at a rate of 10°C / min and calcined at 900°C for 2h to obtain a carbon material.

[0062] Figure 1 The SEM image of the carbon material prepared in this example is shown. It can be seen from the figure that the carbon material has a certain pore structure and a total pore volume of 50.53 cm 3 / g, the average pore diameter is 2.19nm, and the specific surface area is 543.6m 2 / g.

[0063] The carbon material prepared in this example was tested by electron paramagnetic resonance spectroscopy (EPR), which specifically included the following steps: placing the carbon material in a water system, using 2,2,6,6,6-tetramethyl-4-piperidinol (TMP) as a capture agent, using singlet oxygen to react with TMP to generate TMPN free radicals, and using electron paramagnetic resonance EPR to detect TMPN. The test results are shown in Figure 2. Figure 2 As shown in the figure, three 1:1:1 iso-peaks are generated from left to right, indicating that the carbon material produces singlet oxygen in a water system without energy input, light, or oxidant addition.

[0064] The carbon material prepared in this example was subjected to a quencher experiment. The specific experimental steps included: taking 20 mg of the carbon material and placing it in 100 mL of a 20 mg / L sulfamethoxazole solution. In the absence of light and at room temperature (25±1°C), 50 mM chloroform, furfuryl alcohol, dimethyl sulfoxide (DMSO), and tert-butanol were added respectively; 1 mL of the solution was taken with a syringe before the start of the reaction and at 5 min, 10 min, 20 min, 30 min, and 60 min after the start of the reaction, and the solution was quickly filtered with a 0.22 μm filter membrane and injected into a 1.5 mL liquid phase bottle. The concentration of sulfamethoxazole in the solution was detected by high performance liquid chromatography. The experimental results are shown as follows: Figure 4 As shown. Figure 4 It can be seen that the addition of furfuryl alcohol can effectively quench the singlet oxygen generated by the carbon material, reducing the degradation rate of sulfamethoxazole to 15.1%. This shows that the carbon material prepared by the present invention can generate singlet oxygen, which is consistent with the EPR experimental results and has an excellent oxidative degradation effect on sulfamethoxazole. Example 2

[0065] The difference between this embodiment and embodiment 1 is that this embodiment uses bamboo instead of dichotoma.

[0066] The rest of the preparation methods and parameters remained the same as in Example 1.

[0067] Example 3

[0068] The difference between this embodiment and embodiment 1 is that the carbonization temperature in step (2) is 400°C.

[0069] The rest of the preparation methods and parameters remained the same as in Example 1.

[0070] Example 4

[0071] The difference between this embodiment and embodiment 1 is that the carbonization temperature in step (2) is 500°C.

[0072] The rest of the preparation methods and parameters remained the same as in Example 1.

[0073] Example 5

[0074] The difference between this embodiment and embodiment 1 is that the carbonization temperature in step (2) is 700°C.

[0075] The rest of the preparation methods and parameters remained the same as in Example 1.

[0076] Example 6

[0077] The difference between this embodiment and embodiment 1 is that the calcination time in step (3) is 1 hour.

[0078] The rest of the preparation methods and parameters remained the same as in Example 1.

[0079] Example 7

[0080] This embodiment provides a method for preparing carbon materials from agricultural and forestry waste resources, the method comprising the following steps:

[0081] (1) The rice straw was dried at 105°C for 48 h and then ball-milled to obtain a powder with an average particle size of 80 mesh;

[0082] (2) heating the powder in a tube furnace under an argon atmosphere at a rate of 10°C / min and carbonizing at 800°C for 1 hour to obtain biochar;

[0083] (3) The biochar was heated in a muffle furnace under air conditions at a rate of 5°C / min and calcined at 800°C for 3 hours to obtain a carbon material.

[0084] Example 8

[0085] This embodiment provides a method for preparing carbon materials from agricultural and forestry waste resources, the method comprising the following steps:

[0086] (1) Wheat straw was dried at 150°C for 36 h and then ball-milled to obtain a powder with an average particle size of 300 mesh;

[0087] (2) heating the powder in a tube furnace under an argon atmosphere at a rate of 15°C / min and carbonizing at 400°C for 5 hours to obtain biochar;

[0088] (3) The biochar was heated in a muffle furnace under air conditions at a rate of 15°C / min and calcined at 1000°C for 1 hour to obtain a carbon material.

[0089] Example 9

[0090] The difference between this embodiment and embodiment 1 is that the carbonization temperature in step (2) is 900°C.

[0091] The rest of the preparation methods and parameters remained the same as in Example 1.

[0092] Example 10

[0093] The difference between this embodiment and embodiment 1 is that the carbonization temperature in step (2) is 300°C.

[0094] The rest of the preparation methods and parameters remained the same as in Example 1.

[0095] Example 11

[0096] The difference between this embodiment and embodiment 1 is that the calcination time in step (3) is 4 hours.

[0097] The rest of the preparation methods and parameters remained the same as in Example 1.

[0098] Example 12

[0099] The difference between this embodiment and embodiment 1 is that the calcination time in step (3) is 0.5 h.

[0100] The rest of the preparation methods and parameters remained the same as in Example 1.

[0101] Example 13

[0102] The difference between this embodiment and embodiment 1 is that the calcination temperature in step (3) is 700°C.

[0103] The rest of the preparation methods and parameters remained the same as in Example 1.

[0104] Example 14

[0105] The difference between this embodiment and embodiment 1 is that the calcination temperature in step (3) is 1100°C.

[0106] The rest of the preparation methods and parameters remained the same as in Example 1.

[0107] Comparative Example 1

[0108] The difference between this comparative example and Example 1 is that in step (1), ball milling is not performed, but carbonization is performed directly after drying.

[0109] The rest of the preparation methods and parameters remained the same as in Example 1.

[0110] Comparative Example 2

[0111] The difference between this comparative example and Example 1 is that step (2) is not performed, but the powder is directly calcined.

[0112] The rest of the preparation methods and parameters remained the same as in Example 1.

[0113] Performance Testing

[0114] The carbon materials prepared in Examples 1-14 and Comparative Examples 1-2 were used to perform an experiment on degradation of the antibiotic sulfamethoxazole in water. The specific experimental steps included:

[0115] 20 mg of each carbon material was placed in 100 mL of a 20 mg / L sulfamethoxazole solution. The reaction was carried out in the absence of light at room temperature (25 ± 1°C) with a stirring rate of 500 rpm. Samples were taken at 5, 10, 20, 30, and 60 minutes. The sulfamethoxazole concentration in the reaction solution was determined using high-performance liquid chromatography (HPLC). The mobile phase consisted of a 3:7 volume ratio of methanol and 1 wt.% phosphoric acid solution. The sulfamethoxazole concentration ratio (C / C0) was calculated as: sulfamethoxazole concentration in the solution at the measurement time / initial sulfamethoxazole concentration × 100%. When the sulfamethoxazole concentration in the solution remained stable, the degradation rate of sulfamethoxazole was calculated as: degradation rate = 1 - concentration ratio.

[0116] The test results are as follows Figure 3 and as shown in Table 1.

[0117] Figure 3 The graph shows the concentration ratio results of the experiment of oxidizing and removing sulfamethoxazole using the carbon material prepared in Example 1. As can be seen from the graph, the carbon material prepared in Example 1 can degrade and remove 61.3% of sulfamethoxazole within 5 minutes and 95.5% of sulfamethoxazole within 60 minutes by efficiently producing singlet oxygen.

[0118] also, Figure 5 and Figure 6 The results of the anti-ion interference experiment of the carbon material prepared in Example 1 are shown in FIG. Figure 3 The degradation curve shown in the figure shows that the carbon material prepared in this example has excellent anti-ion interference performance.

[0119] Figure 7 The schematic diagram shows the experimental results of removing sulfamethoxazole under different pH conditions using the carbon material prepared in Example 1, wherein the control group is Figure 3 As shown in the degradation curve, it can be seen from the figure that the carbon material has excellent acid and alkali resistance, and the stronger the acidity, the better the degradation performance of sulfamethoxazole.

[0120] Table 1

[0121] Whether singlet oxygen is produced Degradation rate (%) Example 1 yes 95.5 Example 2 yes 93.2 Example 3 yes 86.9 Example 4 yes 86.5 Example 5 yes 85.7 Example 6 yes 85.3 Example 7 yes 93.8 Example 8 yes 94.4 Example 9 yes 65.1 Example 10 yes 69.3 Example 11 yes 56.9 Example 12 yes 55.1 Example 13 yes 55.2 Example 14 yes 58.1 Comparative Example 1 yes 8.1 Comparative Example 2 no 4.7

[0122] analyze:

[0123] The data results of Examples 1-8 show that the carbon material prepared by the present invention under multiple specific parameter ranges can produce singlet oxygen under the conditions of no energy input, no light, and no addition of oxidant, and can remove sulfamethoxazole from water, and can have an excellent oxidative degradation effect on sulfamethoxazole, and the degradation rate of sulfamethoxazole in water can reach more than 85%.

[0124] The data results of Examples 1 and 2 show that the raw material for Example 1 is Dicranopteris dichotoma, while the raw material for Example 2 is bamboo. The carbon material prepared using Dicranopteris dichotoma as the raw material achieved a degradation rate of 95.5% for 20 mg / L of sulfamethoxazole within 60 minutes. Under the same conditions, the material prepared using bamboo as the raw material also achieved a degradation rate of 93.2% for 20 mg / L of sulfamethoxazole within 60 minutes. This demonstrates that the carbon materials of the present invention prepared using different agricultural and forestry wastes as raw materials all have good singlet oxygen production and oxidative degradation effects on organic pollutants.

[0125] From the data results of Examples 1 and 9-10, it can be seen that if the carbonization temperature is too high, that is, at 900°C, the pore structure of the carbon material will collapse, and the total pore volume and specific surface area will be small; the degradation rate of the prepared carbon material for 20 mg / L sulfamethoxazole is only 65.1%; if the carbonization temperature is too low, that is, at 300°C, the carbon material will not be able to effectively form a pore structure, and the total pore volume and specific surface area will also be small. The degradation rate of the prepared carbon material for 20 mg / L sulfamethoxazole is only 56.9%. This shows that the present invention preferably controls the carbonization temperature in the preparation method to 400-800°C, which can make the carbon material have a larger total pore volume and specific surface area, which is conducive to the subsequent calcination to produce carbon vacancies and singlet oxygen, and has excellent oxidative degradation effect.

[0126] From the data results of Examples 1 and 11-12, it can be seen that if the calcination time is too long, that is, 4 hours, the carbon material easily burns into carbon fragments, which is not conducive to the generation of singlet oxygen; the degradation rate of the prepared carbon material for 20 mg / L sulfamethoxazole is only 56.9%; if the calcination time is too short, that is, 0.5 hours, the carbon material cannot effectively form carbon vacancies, which is not conducive to the generation of singlet oxygen; the degradation rate of the prepared carbon material for 20 mg / L sulfamethoxazole is only 55.1%. This shows that the present invention preferably controls the calcination time in the preparation method to 1-3 hours, which can enable the carbon material to effectively form carbon vacancies, facilitate the generation of singlet oxygen, and have a good oxidative degradation effect.

[0127] From the data results of Examples 1 and 13-14, it can be seen that if the calcination temperature is too low, the carbon material cannot effectively form carbon vacancies, which is not conducive to the generation of singlet oxygen and will result in a low antibiotic removal rate; if the calcination temperature is too high, the carbon material is easily burned into carbon fragments, which is not conducive to the generation of singlet oxygen and will result in a decrease in the antibiotic removal rate.

[0128] It can be seen from the data results of Example 1 and Comparative Example 1 that if the raw materials are not ball-milled, it will be detrimental to the full carbonization of the raw materials, resulting in a smaller total pore volume and specific surface area of ​​the prepared carbon material, which is not conducive to the subsequent calcination to produce carbon vacancies and the degradation and removal of antibiotics.

[0129] From the data results of Example 1 and Comparative Example 2, it can be seen that if the powder is directly calcined, a graphite-type carbon structure and effective carbon vacancies cannot be formed, which will result in the carbon material being unable to produce singlet oxygen and having a weak ability to degrade antibiotics.

[0130] The applicant states that while the above-described embodiments illustrate the process of the present invention, the present invention is not limited to the above-described process steps, nor does it imply that the present invention must rely on the above-described process steps for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing carbon materials from agricultural and forestry waste resources, characterized in that: The method comprises the following steps: (1) Grinding agricultural and forestry waste to obtain powder; The agricultural and forestry waste in step (1) includes any one of dichotoma, bamboo, rice straw, wheat straw or corn straw, or a combination of at least two thereof; (2) carbonizing the powder to obtain biochar; (3) calcining the biochar to obtain the carbon material containing carbon vacancies; The carbonization temperature in step (2) is 400-800° C., the calcination temperature is 800-1000° C., the calcination time is 1-3 hours, and the calcination in step (3) is carried out in air.

2. The method according to claim 1, characterized in that The agricultural and forestry waste in step (1) is Dicranopteris dichotoma.

3. The method according to claim 1, characterized in that The average particle size of the powder in step (1) is 80-300 mesh.

4. The method according to claim 1, wherein Before the agricultural and forestry wastes are crushed in step (1), they are first dried.

5. The method according to claim 4, characterized in that The temperature of the drying process is 105-150°C.

6. The method according to claim 4, characterized in that The drying time is 24-48 hours.

7. The method according to claim 1, characterized in that The carbonization in step (2) is carried out in a protective atmosphere.

8. The method according to claim 7, characterized in that The gas in the protective atmosphere includes any one of nitrogen, carbon dioxide or inert gas, or a combination of at least two of them.

9. The method according to claim 8, characterized in that The inert gas includes argon.

10. The method according to claim 1, characterized in that The carbonization temperature in step (2) is 600-650°C.

11. The method according to claim 1, wherein The carbonization time in step (2) is 1-5 hours.

12. The method according to claim 1, characterized in that The heating rate of the carbonization in step (2) is 5-15°C / min.

13. The method according to claim 1, wherein The heating rate of the calcination is 5-15°C / min.

14. The method according to claim 1, wherein The method comprises the following steps: (1) Drying the Dicranopteris dichotoma at 105-150°C for 24-48 hours, and then crushing the powder to obtain a powder with an average particle size of 80-300 mesh; (2) heating the powder at a rate of 5-15°C / min in a protective atmosphere and carbonizing at 400-800°C for 1-5 hours to obtain biochar; (3) The biochar is heated at a rate of 5-15°C / min under air conditions, and then calcined at 800-1000°C for 1-3 hours to obtain a carbon material.

15. A carbon material, characterized in that The carbon material is prepared by the method according to any one of claims 1 to 14.

16. The carbon material according to claim 15, characterized in that The specific surface area of ​​the carbon material is 300-800m 2 / g.

17. The carbon material according to claim 15, characterized in that The carbon material has a porous structure.

18. The carbon material according to claim 15, characterized in that The total pore volume of the carbon material is 40-60 cm 3 / g.

19. The carbon material according to claim 15, characterized in that The average pore diameter of the carbon material is 1.5-2.5 nm.

20. A use of the carbon material according to claim 15, characterized in that: The carbon material is used in the field of water treatment containing organic matter.

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