Preparation method of sulfydryl grafted sponge structure biochar for removing new pollutants

Abstract

The invention provides a preparation method of sulfydryl grafted sponge structure biochar for removing new pollutants, which comprises the following steps: step S1, placing a cow dung precursor in a porcelain boat, then transferring into a tubular furnace, and heating in N2 atmosphere for calcining reaction; s2, after cooling to room temperature, washing the calcined product to ionic strength by using pure water and absolute methanol in a suction filtration and washing manner, so as to obtain original sponge structure biochar; s3, mixing and dispersing the sponge structure charcoal, 6-mercaptopyridine-3-carboxylic acid and N, N '-dicyclohexylcarbodiimide into an N, N-dimethylformamide organic solvent, and carrying out ultrasonic mixing and uniform dispersion; s4, heating the mixed solution in an oil bath under the condition of N2, cooling the mixed solution to room temperature, washing the mixed solution with pure water, and performing vacuum drying to obtain the sulfydryl graft modified sponge structure biochar.

Description

Technical Field

[0001] The technical field involved in the present invention, in particular, relates to a preparation method of a mercapto-grafted sponge-structured biochar for removing emerging pollutants. Background Art

[0002] Emerging pollutants usually have biological toxicity, environmental persistence, and bioaccumulation, which may lead to endocrine disorders, antibiotic resistance, and carcinogenicity in humans, aquatic animals, and wild animals. Even at low concentrations, organisms can cause long-term poisoning in the body after being exposed to emerging pollutants. [1-2] , which poses a serious threat to the health and safety of humans and other organisms in the ecological environment. More importantly, in the process of livestock and poultry farming, various antibiotics, such as sulfonamide antibiotics and tetracycline antibiotics, are widely used to ensure the healthy growth of livestock and poultry. However, most antibiotics are discharged into the environment through livestock and poultry manure. The antibiotics present in water bodies not only bring direct biological toxicity to aquatic plants and animals, but also easily cause antibiotic resistance genes in the microorganisms in the environment, seriously endangering the ecological safety of rural waters. [3] . Therefore, in order to cope with the development of other industries such as livestock and poultry farming and the rapid growth of the population, it is urgent to effectively remove highly toxic and refractory emerging pollutants through green and environmentally friendly treatment technologies.

[0003] Among existing new pollutant treatment technologies, due to their low cost and environmental friendliness, advanced oxidation technologies based on H2O2 activation (H2O2-AOPs) have attracted extensive attention in recent years and are considered an important strategy for effectively removing new pollutants. Specifically, AOPs usually generate reactive oxygen species with high redox potentials (·OH, E0~2.7 V; O2·-, E0~0.94 V) to achieve efficient removal of recalcitrant new pollutants in the aqueous phase [4-5]. However, traditional H2O2-AOPs have problems such as a narrow pH application range and difficult recovery [6]. To overcome these limitations, heterogeneous activation of H2O2 technology plays an important role in the field of H2O2-AOPs. For example, the research by Lu et al. showed that Cu-Zn-Fe-LDH achieved complete degradation of acetaminophen within 24 hours by activating H2O2. Cu-Zn-Fe-LDH provided more metal sites to accelerate the cycling of iron and copper, and was further transformed into CuI-OH and ·OH through the electron transfer of CuII-OOH, thus improving the degradation performance of new pollutants [7]. In addition, the research by Xu et al. demonstrated that metal selenides could also be used as heterogeneous catalysts to activate H2O2, indicating that the degradation rate of flavomycin in the CuCoSe / H2O2 system was 97% within 10 minutes [8]. It is worth noting that Liu et al. constructed a metal-free electro-Fenton system mediated by nitrogen-doped activated carbon modified graphite felt (NACs / GF) to achieve effective degradation of sulfamethazine by efficiently activating H2O2 [9]. However, due to using metals as reaction sites, metal-site catalysts often have the problem of metal ion leaching, which may cause secondary pollution to the environment

[10] . More importantly, multifunctional composite materials formed by combining active components, heterogeneous carriers, and other building blocks often require a large amount of reagent and energy input, resulting in a high preparation cost

[11] . At the same time, sparse active sites are easily formed through high-temperature calcination, and the active sites are difficult to predict, which fundamentally hinders the further improvement of catalytic performance

[12] . Therefore, it is of great significance to develop novel heterogeneous catalysts through efficient synthesis routes and less consumption to minimize costs as much as possible and achieve the practical application of a novel material.

[0004] As a carbonaceous porous material, biochar can be prepared from waste raw materials such as agricultural by-products, sludge, and animal manure, which helps in the management and utilization of waste. Its easy batch preparation and stability in the environment enable the catalyst to be reused. Therefore, using biochar for environmental remediation has been proven to be a sustainable method. For example, after acid treatment of biochar by Luo et al., the acid-modified BC / H 2 O 2 system achieved a 93.0% removal rate of carbamazepine within 24 hours

[15] On the other hand, Zhang et al. impregnated biochar with iron, which not only increased the specific surface area of biochar but also provided more active sites to activate H 2 O 2 , achieving efficient degradation of sulfamethoxazole

[16] . However, the current biochar modification and activation of H 2 O 2 technology still has limitations such as unclear active sites, difficulty in controllability, and leaching of metal site ions. It is worth noting that the abundant inherent amino groups exposed on the surface of biochar endow it with great potential to regulate its functional activity at the molecular level through interface structure engineering

[17] , and this technology can form clear active sites on the catalyst surface and form high chemical stability, which is conducive to the significant improvement of catalytic performance

[18] . So far, there have been relevant reports on the application of interface site engineering in other fields. For example, Lai et al. grafted 5-bromo-2-thiophenecarboxaldehyde on the edge of carbon nitride as an electron-withdrawing site to achieve excellent photocatalytic degradation of oxytetracycline

[19] . Kim et al. achieved a significant improvement in the photocatalytic synthesis of H 2 O 2 performance by anchoring anthraquinone on the edge of carbon nitride as an electron-withdrawing site

[20] . However, the construction of modified biochar by interface grafting site engineering for heterogeneous activation of H 2 O 2 advanced oxidation technology has been somewhat neglected to a certain extent

[0005] In summary, in this invention, through a fine interface site engineering technology, mercapto functional sites were grafted onto the surface of sponge-structured biochar (BIO), successfully constructing a new type of mercapto-grafted modified sponge-structured biochar (BIO-P-COOH). Using the heterogeneous activation of H 2 O 2 technology, efficient degradation of new sulfonamide pollutants was achieved. Through advanced characterization methods such as X-ray powder diffraction technology, Fourier transform infrared spectroscopy analysis, X-ray photoelectron spectroscopy, and scanning electron microscopy, the surface physical property information and material morphology of BIO and BIO-P-COOH were analyzed in detail. Using high-performance liquid chromatography analysis technology, the dosage of BIO modification synthesis was optimized, and the corresponding efficacy and performance stability of BIO and BIO-P-COOH in degrading new sulfonamide pollutants were determined. Based on this, developing a green and environmental protection economy, implementing the scientific environmental concept of reclaimed water utilization, and developing a preparation method of a mercapto-grafted modified sponge-structured biochar as a new material for effectively removing new pollutants have practical significance for efficiently improving the water environment and having positive environmental, social, and economic benefits Summary of the Invention

[0006] The object of the present invention is to provide a preparation method and an application method of a mercapto-grafted sponge-structured biochar that can improve the comprehensive performance of biochar and reduce the secondary pollution of traditional heterogeneous catalytic activation technology.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A preparation method of a mercapto-grafted modified sponge-structured biochar, comprising the following steps:

[0009] Step S1: Place the cow dung precursor in a porcelain boat, and then transfer it to a tube furnace for calcination reaction under N 2 atmosphere while heating up.

[0010] Step S2: After cooling to room temperature, wash the calcined product by suction filtration with pure water and anhydrous methanol until the ionic strength is reached, to obtain the original sponge-structured biochar.

[0011] Step S3: Mix and disperse the sponge-structured biochar, 6-mercaptopyridine-3-carboxylic acid, and N,N'-dicyclohexylcarbodiimide in an organic solvent of N,N-dimethylformamide, and ultrasonically mix and disperse them evenly.

[0012] Step S4: Heat the mixed solution by oil bath under N 2 condition. After cooling to room temperature, wash it with pure water and dry it under vacuum to obtain the mercapto-grafted modified sponge-structured biochar.

[0013] Preferably, in the step S1, the heating rate of calcination under N 2 atmosphere is 10 °C·min -1 , the holding time at the temperature is 4 hours, and the calcination temperature is 700 °C.

[0014] Preferably, in the step S2, the ionic strength is 20 μs·cm -1 , and the number of times of washing the product is 3 - 4 times.

[0015] Preferably, in the step S3, the amount of the sponge-structured biochar used is 0.1 g, the amount of 6-mercaptopyridine-3-carboxylic acid used is preferably 0.5 g, the amount of N,N'-dicyclohexylcarbodiimide used is preferably 0.5 g, the amount of N,N-dimethylformamide used is 15 mL, and the ultrasonic mixing and dispersion time is 15 minutes.

[0016] Preferably, in the step S4, the temperature of the oil bath heating is 85 °C, the heating time is 24 hours, the vacuum drying temperature is 60 °C, and the number of times of washing the product is 3 - 4 times.

[0017] The present invention also provides an application method of the thiol-grafted modified sponge structure biochar prepared by the preparation method of the thiol-grafted modified sponge structure biochar for removing new sulfonamide pollutants, by utilizing the amide reaction between the amino groups inherently existing on the surface of the biochar and the carboxyl groups at the edge of the 6-thiopyridine-3-carboxylic acid functional ligand, the thiol functional sites are successfully grafted on the surface of the biochar, and the grafted thiol groups can act as H without any energy input. 2 O 2 Adsorption and reaction sites

[21] Through the electron transfer between biochar and functional grafted functional groups, H 2 O 2 , and generate active oxygen species to achieve efficient degradation of new sulfonamide pollutants.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The novel catalyst prepared by the present invention can fully degrade new pollutants that are difficult to degrade in the water environment, such as sulfamethoxazole, sulfadiazine, etc.

[0019] (2) The preparation technology provided by the present invention can provide a simple, low-cost, low-energy, green, environmentally friendly and efficient new method for advanced oxidation technology based on heterogeneous activation, which improves the limitations of traditional heterogeneous catalytic activation technology such as secondary pollution and high energy consumption, improves the comprehensive performance of biochar, and develops a new, green, sustainable and stable Fenton-like system, which has great potential in the field of environmental remediation and has practical significance for positive environmental, economic and social benefits.

[0020] (3) The base biochar of the novel catalyst prepared by the present invention can be obtained from waste materials such as agricultural by-products and animal manure, which is helpful for the management and utilization of waste. It has the advantages of easy batch preparation and stability in the environment, and can be used as an important strategy of "turning waste into treasure".

[0021] (4) The novel modified application material of the present invention has excellent performance in degrading new pollutants, and at the same time has excellent properties such as low cost, green environmental protection, high mechanical strength, thermal stability and chemical resistance.

[0022] (5) The novel modified application material of the present invention has the advantages of abundant availability, extremely low toxicity, simple preparation technology, diverse sizes and shapes, and better stability, and has great application prospects in the fields of environment and catalysis.

[0023] (6) The preparation method of the present invention requires simple equipment, is easy to operate, has low cost and high feasibility.

[0024] In summary, the present invention is directed to the existing heterogeneous H 2 O 2The activation technology has key problems such as the leaching of metal ions at metal sites causing secondary pollution, the relatively high preparation cost of functional catalysts, the addition of a large amount of reagents and energy, and the formation of sparse and unpredictable active sites during high-temperature calcination. Through the interfacial site grafting engineering, the present invention develops a preparation method of a novel material, namely a sponge-structured biochar grafted with mercapto groups, for effectively removing emerging pollutants.

[0025] The technology provided by the present invention can provide a simple, low-cost, low-energy-consuming, green, environmentally friendly and efficient novel method for the advanced oxidation technology based on heterogeneous activation, improve the limitations of traditional heterogeneous catalytic activation technologies such as secondary pollution and high energy consumption, improve the comprehensive performance of biochar, develop a novel, green, sustainable and stable Fenton-like system, and has great potential in the field of environmental remediation, showing positive environmental and social benefits. Brief Description of the Drawings

[0026] Figure 1 It is a process schematic diagram of a preparation method of a sponge-structured biochar grafted with mercapto groups provided for the embodiment of the present invention; Figure 1 ;

[0027] Figure 2 It is a schematic diagram of X-ray powder diffraction analysis of crystal phase characterization in the embodiment of the present invention;

[0028] Figure 3 It is a schematic diagram of Fourier transform infrared spectroscopy characterization analysis and X-ray photoelectron spectroscopy analysis in the embodiment of the present invention;

[0029] Figure 4 It is a schematic diagram of scanning electron microscope morphology analysis in the embodiment of the present invention;

[0030] Figure 5 It is a schematic diagram of various tests in the embodiment of the present invention;

[0031] Figure 6 It is a process schematic diagram of a preparation method of a sponge-structured biochar grafted with mercapto groups provided for the embodiment of the present invention; Figure 2 。 Detailed Embodiments

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0033] As Figure 1 and Figure 6 shown, a preparation method of a sponge-structured biochar grafted with mercapto groups provided for this embodiment is as follows:

[0034] Step S1: The cow dung precursor was placed in a porcelain ark and then transferred to a tube furnace at N 2 The temperature was raised in the atmosphere for calcination reaction; the heating rate was 10 ℃·min -1 , calcined at 700 °C for 4 h.

[0035] Step S2: After cooling to room temperature, the calcined product is washed 3-4 times with pure water and anhydrous methanol to an ionic strength of 20 μs·cm -1 , and the original sponge-structured biochar (BIO) was obtained.

[0036] Step S3: 0.1 g of sponge-structured biochar (BIO), 0.5 g of 6-mercaptopyridine-3-carboxylic acid (P-COOH), and 0.5 g of N,N'-dicyclohexylcarbodiimide (DCC) were dispersed in 15 mL of N,N-dimethylformamide (DMF) organic solvent and uniformly dispersed by ultrasonic mixing for 15 minutes.

[0037] Step S4: The mixed solution was stirred under N 2 The amidation reaction was carried out by heating in an 85 ℃ oil bath for 24 hours under the same conditions. After cooling to room temperature, it was washed with pure water for 3 to 4 times and dried in a vacuum at 60 ℃ to obtain the sponge-structured biochar (BIO-P-COOH) modified by thiol grafting.

[0038] When the thiol-grafted sponge-structured biochar prepared by the above preparation method is used to remove new sulfonamide pollutants, the thiol functional sites are successfully grafted on the biochar surface by utilizing the amide reaction between the inherent amino groups on the biochar surface and the carboxyl groups on the edge of the 6-thiopyridine-3-carboxylic acid functional ligand. The grafted thiol groups can act as H 2 O 2 Adsorption and reaction sites

[21] Through the electron transfer between biochar and functional grafted functional groups, H 2 O 2 , and generate active oxygen species to achieve efficient degradation of new sulfonamide pollutants.

[0039] like Figure 2 As shown, Figure 2 The left side (a) is the original sponge structure biochar, and the right side (b) is the sponge structure biochar modified by thiol grafting. Through X-ray powder diffraction analysis technology, it can be seen that the similar diffraction peaks before and after modification indicate that the introduction of thiol functional active sites will not lead to significant changes in the main crystal structure and crystal phase of biochar.

[0040] like Figure 3 As shown, Figure 3On the left side (a) is the Fourier transform infrared spectroscopy (FTIR) characterization analysis, and on the right side (b) is the X-ray photoelectron spectroscopy (XPS) analysis. According to the FTIR analysis results, different from BIO, BIO-P-COOH shows C-N and N-H stretching vibration peaks of amide bonds at the characteristic peak positions of 1628 cm -1 and 1533 cm -1 respectively. Compared with the P-COOH monomer, the BIO-P-COOH infrared curve shows a characteristic peak of thiol (C=S) at 1575 cm -1 . The above results successfully prove that the thiol group has been successfully grafted onto the surface of the sponge-structured biochar. As Figure 3 shown in b, through XPS analysis, it is known that the peak value of the S element in the modified biochar increases, further proving the successful grafting of the thiol group.

[0041] As Figure 4 shown, Figure 4 in (a) is the biochar formed by calcination at 400 °C; (b) is the biochar formed by calcination at 700 °C; (c) is the biochar formed by calcination at 700 °C; (d) is the prepared BIO-P-COOH.

[0042] As Figure 4 shown in (a)-(c), when the cow dung precursor is calcined at 400 °C and 900 °C, the material morphology is a stack of complex carbon sheets. When calcined at 700 °C, a sponge structure with clear structure, porous and high specific surface area is formed. The characteristic of high specific surface area is conducive to the effective grafting of functional groups and the progress of catalytic activation reactions. Therefore, the calcination temperature is preferably 700 °C. At the same time, as Figure 4 shown in (d), BIO-P-COOH shows a sponge structure similar to that of biochar, indicating that the introduction of thiol functional groups does not cause a significant change in the biochar structure.

[0043] As Figure 5 shown, Figure 5 in (a) is the degradation performance test under different dosages of functional monomers; (b) is the degradation performance test under different dosages of functional monomers; (c) is the SDZ degradation efficiency test; (d) is the SMZ degradation efficiency test.

[0044] As Figure 5 shown in (a), as the dosage of the P-COOH functional monomer increases from 0.1 g to 0.5 g, the performance of BIO-P-COOH in activating H 2 O 2 to degrade sulfamethoxazole (SMX) is significantly improved, indicating that the increase in thiol functional groups is beneficial to improving the reaction activity of the BIO-P-COOH / H 2 O 2 system, proving its use as a catalyst for activating H2 O 2 The reactive sites of O. However, as the dosage of P-COOH increased from 0.5 g to 0.9 g, the activity of the BIO-P-COOH / H 2 O 2 reaction system began to decline, indicating that excessive addition of the P-COOH functional monomer might cover the original reaction sites, leading to a decrease in the activation performance of the system. Therefore, the preferred dosage of P-COOH is 0.5 g. As shown in Figure 5 (b), through four active cycle tests, it can be seen that the activity of the BIO-P-COOH / H 2 O 2 reaction system did not change significantly after four cycles, proving its reaction stability. As shown in Figure 5 (c)-(d), through the analysis of the degradation activities of BIO / H 2 O 2 and BIO-P-COOH / H 2 O 2 systems for sulfamethazine (SMZ) and sulfadiazine (SDZ), it can be seen that the BIO-P-COOH / H 2 O 2 reaction system showed high degradation performance for the two new sulfonamide pollutants.

[0045] The following is a detailed description in combination with specific parameters:

[0046] Example 1

[0047] First, weigh 50 g of cow dung precursor and place it in a dry porcelain ark, and transfer it to a tube furnace. Under the condition that the room temperature is used as the initial calcination temperature, in N 2 atmosphere, increase the temperature to 400 °C at a heating rate of 10 °C·min -1 . After maintaining the highest calcination temperature for 4 hours, cool the product to room temperature, and transfer the solid sample in the porcelain ark to a mortar. Crush the large particles into small particles, and then wash the calcined product with pure water and anhydrous methanol until the ionic strength is 20 μs·cm -1 , that is, the original sponge-structured biochar (BIO-400) calcined at 400 °C is obtained.

[0048] Example 2

[0049] First, weigh 50 g of cow dung precursor and place it in a dry porcelain ark, and transfer it to a tube furnace. Under the condition that the room temperature is used as the initial calcination temperature, in N 2 atmosphere, increase the temperature to 400 °C at a heating rate of 10 °C·min -1After raising the temperature to 700 °C at a heating rate, maintaining the highest calcination temperature for 4 hours, cooling the product to room temperature, transferring the solid sample in the porcelain boat to a mortar, crushing the large particles into small particles, and then washing the calcined product with pure water and anhydrous methanol until the ionic strength is 20 μs·cm -1 , the original sponge-structured biochar (BIO-700) calcined at 700 °C is obtained.

[0050] Example 3

[0051] First, weigh 50 g of cow dung precursor and place it in a dry porcelain boat, then transfer it to a tubular furnace. Under the condition of taking room temperature as the initial calcination temperature, in N 2 atmosphere, raise the temperature to 900 °C at a heating rate of 10 °C·min -1 . After maintaining the highest calcination temperature for 4 hours, cool the product to room temperature, transfer the solid sample in the porcelain boat to a mortar, crush the large particles into small particles, and then wash the calcined product with pure water and anhydrous methanol until the ionic strength is 20 μs·cm -1 , the original sponge-structured biochar (BIO-900) calcined at 900 °C is obtained.

[0052] Example 4

[0053] Weigh 0.1 g of BIO-700 and transfer it to a 100 mL thick-walled pressure-resistant bottle. Then, add 0.1 g of 6-mercaptopyridine-3-carboxylic acid (P-COOH) and 0.1 g of N,N'-dicyclohexylcarbodiimide (DCC) into the bottle to mix with BIO-700. Add 15 mL of N,N-dimethylformamide (DMF) into the reaction bottle, and ultrasonicate for 15 minutes. After the three are evenly mixed and dispersed in the bottle, use a magnetic heating stirrer for oil bath heating, and heat at 85 °C for 24 hours under N 2 conditions to promote the amidation reaction between P-COOH and BIO-700. After the reaction is completed, wash the reaction product with pure water and dry it under vacuum at 60 °C to obtain the novel thiol-grafted modified sponge-structured biochar (BIO-P-COOH 0.1 ).

[0054] Example 5

[0055] Weigh 0.1 g of BIO-700 and transfer it to a 100 mL thick-walled pressure-resistant bottle. Subsequently, add 0.3 g of 6-mercaptopyridine-3-carboxylic acid (P-COOH) and 0.3 g of N,N'-dicyclohexylcarbodiimide (DCC) into the bottle to mix with BIO-700. Add 15 mL of N,N-dimethylformamide (DMF) into the reaction bottle, and ultrasonicate for 15 minutes. After the three are evenly mixed and dispersed in the bottle, heat it in an oil bath using a magnetic heating stirrer. Under N 2 conditions, heat at 85 °C for 24 hours to promote the amidation reaction between P-COOH and BIO-700. After the reaction is completed, wash the reaction product with pure water and vacuum dry it at 60 °C to obtain the novel thiol-grafted modified sponge-structured biochar (BIO-P-COOH 0.3 ).

[0056] Example 6

[0057] Weigh 0.1 g of BIO-700 and transfer it to a 100 mL thick-walled pressure-resistant bottle. Subsequently, add 0.5 g of 6-mercaptopyridine-3-carboxylic acid (P-COOH) and 0.5 g of N,N'-dicyclohexylcarbodiimide (DCC) into the bottle to mix with BIO-700. Add 15 mL of N,N-dimethylformamide (DMF) into the reaction bottle, and ultrasonicate for 15 minutes. After the three are evenly mixed and dispersed in the bottle, heat it in an oil bath using a magnetic heating stirrer. Under N 2 conditions, heat at 85 °C for 24 hours to promote the amidation reaction between P-COOH and BIO-700. After the reaction is completed, wash the reaction product with pure water and vacuum dry it at 60 °C to obtain the novel thiol-grafted modified sponge-structured biochar (BIO-P-COOH 0.5 ).

[0058] Example 7

[0059] Weigh 0.1 g of BIO-700 and transfer it to a 100 mL thick-walled pressure-resistant bottle. Subsequently, add 0.7 g of 6-mercaptopyridine-3-carboxylic acid (P-COOH) and 0.7 g of N,N'-dicyclohexylcarbodiimide (DCC) into the bottle to mix with BIO-700. Add 15 mL of N,N-dimethylformamide (DMF) into the reaction bottle, and ultrasonicate for 15 minutes. After the three are evenly mixed and dispersed in the bottle, heat it in an oil bath using a magnetic heating stirrer. Under N 2 conditions, heat at 85 °C for 24 hours to promote the amidation reaction between P-COOH and BIO-700. After the reaction is completed, wash the reaction product with pure water and vacuum dry it at 60 °C to obtain the novel thiol-grafted modified sponge-structured biochar (BIO-P-COOH 0.7 ).

[0060] Example 8

[0061] Weigh 0.1 g of BIO-700 and transfer it to a 100 mL thick-walled pressure-resistant bottle. Subsequently, add 0.9 g of 6-mercaptopyridine-3-carboxylic acid (P-COOH) and 0.9 g of N,N'-dicyclohexylcarbodiimide (DCC) into the bottle to mix with BIO-700. Add 15 mL of N,N-dimethylformamide (DMF) into the reaction bottle, and ultrasonicate for 15 minutes. After the three are evenly mixed and dispersed in the bottle, heat them in an oil bath using a magnetic heating stirrer. Under N 2 conditions, heat at 85 °C for 24 hours to promote the amidation reaction between P-COOH and BIO-700. After the reaction is completed, wash the reaction product with pure water and dry it under vacuum at 60 °C to obtain the novel thiol-grafted modified sponge-structured biochar (BIO-P-COOH 0.9 ).

[0062] The technology provided in this example can provide a simple, low-cost, low-energy-consuming, green, environmentally friendly, and efficient novel method for advanced oxidation technology based on heterogeneous activation, improving the limitations of traditional heterogeneous catalytic activation technology such as secondary pollution and high energy consumption, enhancing the comprehensive performance of biochar, developing a novel, green, sustainable, and stable Fenton-like system, which has great potential in the field of environmental remediation and shows positive environmental and social benefits and practical significance.

[0063] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0064] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0065] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention should cover within the protection scope of the present invention any equivalent substitution or change made according to the technical solution and inventive concept of the present invention.

Claims

1. A method for preparing a thiol-grafted sponge-structured biochar for removing new pollutants, characterized in that: The steps include: Step S1: placing the cow dung precursor in a porcelain ark, then transferring it to a tube furnace, and heating it in a N2 atmosphere for calcination reaction; Step S2: After cooling to room temperature, the calcined product is washed to ionic strength using pure water and anhydrous methanol by suction filtration to obtain the original sponge structure biochar; Step S3: mixing and dispersing the sponge structure biochar, 6-mercaptopyridine-3-carboxylic acid, and N,N'-dicyclohexylcarbodiimide in an organic solvent of N,N-dimethylformamide, and uniformly dispersing by ultrasonic mixing; Step S4: The mixed solution is heated in an oil bath under N2 conditions, and after being cooled to room temperature, it is washed with pure water and vacuum dried to obtain a sponge-structured biochar modified by thiol grafting.

2. The method for preparing a thiol-grafted sponge-structured biochar for removing new pollutants according to claim 1, characterized in that: In the step S1, the heating rate of the calcination in the N2 atmosphere is 10 °C min -1 , the temperature maintenance time is 4 hours and the calcination temperature is 700 ℃.

3. The method for preparing a thiol-grafted sponge-structured biochar for removing new pollutants according to claim 1, characterized in that: The ion intensity in step S2 is 20 μs·cm -1 , the product is washed 3 to 4 times.

4. The method for preparing a thiol-grafted sponge-structured biochar for removing new pollutants according to claim 1, characterized in that: In the step S3, the amount of the sponge structure biochar is 0.1 g, the amount of 6-mercaptopyridine-3-carboxylic acid is preferably 0.5 g, the amount of N,N'-dicyclohexylcarbodiimide is preferably 0.5 g, the amount of N,N-dimethylformamide is 15 mL, and the ultrasonic mixing and dispersion time is 15 minutes.

5. The method for preparing a thiol-grafted sponge-structured biochar for removing new pollutants according to claim 1, characterized in that: In step S4, the oil bath heating temperature is 85°C, the heating time is 24 hours, the vacuum drying temperature is 60°C, and the product is washed 3 to 4 times.

6. A method for using the thiol-grafted sponge-structured biochar prepared by the method for preparing the thiol-grafted sponge-structured biochar for removing new pollutants according to any one of claims 1 to 5 to remove new pollutants, characterized in that: By utilizing the amide reaction between the inherent amino groups on the biochar surface and the carboxyl groups on the edge of the 6-thiopyridine-3-carboxylic acid functional ligand, the thiol functional sites were successfully grafted onto the biochar surface. Without any energy input, the grafted thiol groups can serve as adsorption and reaction sites for H2O2. [21] Through the electron transfer between biochar and functional grafted functional groups, H2O2 was successfully activated and reactive oxygen species were generated, achieving efficient degradation of new sulfonamide pollutants.

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