Preparation of a copper eutectic solvent-modified biochar catalyst and its application in the activation of persulfate degradation of atrazine.

Abstract

This invention discloses the preparation of a copper eutectic solvent-modified biochar catalyst and its application in the activation of persulfate degradation of atrazine, relating to the fields of water pollution control and environmental functional materials technology. The preparation method includes the following steps: mixing biomass raw materials with acid, impregnating and activating them, and then pre-carbonizing to obtain unmodified biochar; mixing the unmodified biochar with a copper eutectic solvent and carbonizing at high temperature to obtain the copper eutectic solvent-modified biochar catalyst. The preparation method of this invention greatly simplifies the process flow and makes the preparation process efficient and convenient. Simultaneously, the copper eutectic solvent has advantages in dispersibility and low cost, not only effectively loading copper nanoparticles to improve the catalytic activity of biochar, but also significantly reducing the preparation cost. The copper eutectic solvent-modified biochar catalyst prepared by the method of this invention can efficiently activate persulfate degradation of atrazine.

Description

Technical Field

[0001] This invention relates to the fields of water pollution control and environmental functional materials technology, and in particular to the preparation of a copper metal eutectic solvent modified biochar catalyst and its application in the degradation of atrazine by activated persulfate. Background Technology

[0002] Atrazine (ATZ), a highly efficient, low-cost, and long-lasting triazine selective herbicide, is widely used globally for weed control in early-stage crops such as maize, sugarcane, and sorghum. However, after long-term, large-scale use, ATZ continuously enters water bodies through surface runoff and leaching, causing water pollution and posing potential threats to ecosystems and public health. Therefore, developing and optimizing efficient ATZ removal technologies has become a necessary measure to address this pressing environmental challenge.

[0003] Currently, the main treatment processes widely used for removing ATZ from water bodies include biodegradation, physical adsorption, and advanced oxidation processes. Biodegradation has advantages such as low treatment cost and no secondary pollution, and is theoretically an environmentally friendly technology. However, its degradation efficiency is easily affected by environmental factors. Physical adsorption can adsorb pollutant molecules onto the surface of the adsorbent, and is characterized by simple operation, high flexibility, and wide applicability, but it cannot completely remove residual ATZ from water. Advanced oxidation processes are a class of technologies that utilize oxidants to generate highly reactive free radicals, mainly hydroxyl radicals (·OH) and sulfate radicals (SO4·-), thereby efficiently degrading organic pollutants in water. The goal is to completely mineralize pollutants into carbon dioxide, water, and inorganic salts, or at least convert them into smaller molecule intermediates with lower biotoxicity and easier biodegradability. Among these, advanced oxidation processes based on persulfate oxidants have received widespread attention in recent years due to the high oxidation potential, wide applicable pH range, and long free radical half-life of the generated SO4·- radicals. However, the spontaneous generation rate of SO4·- and other free radicals from persulfate is relatively slow, thus requiring an activator to accelerate this process. Common persulfate activation methods include photo / thermal activation, ultraviolet irradiation, and carbon-based material catalysis. Among these, carbon-based materials have become an ideal choice for persulfate activation due to their wide availability, low cost, environmental friendliness, and renewability.

[0004] Biochar is a carbon-rich solid material formed by heating biomass under limited or anaerobic conditions. It boasts advantages such as wide availability of raw materials, low cost, environmental friendliness, and sustainability. However, unmodified raw biochar suffers from problems such as small specific surface area, insufficient polar functional groups, and a lack of active sites, resulting in low activity in catalyzing the degradation of ATZ by persulfate. To improve the ATZ removal performance of biochar, modification is usually required, including physical modification (ball milling, steam activation, etc.), biological modification, and chemical modification (acid-base activation, heteroatom doping, metal salt impregnation, etc.). Transition metals are frequently used to modify biochar to enhance its catalytic performance due to their excellent persulfate activation properties. However, traditional metal doping methods typically require multiple steps, making the preparation process complex. Furthermore, the tendency of metal particles to agglomerate leads to poor dispersibility, limiting the improvement of catalytic performance, and the efficiency remains unsatisfactory. Therefore, developing a simple, economical, and efficient modification method to endow biochar with superior persulfate catalytic activation performance for the efficient degradation of herbicides such as ATZ in water is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a copper eutectic solvent-modified biochar catalyst and its application in the activation of persulfate degradation of ATZ, thereby addressing the problems existing in the prior art. The preparation method of this invention simplifies the biochar modification process, achieving copper doping of biochar in a single high-temperature carbonization process, thus obtaining a highly efficient and stable persulfate activation catalyst.

[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of the present invention: a method for preparing a copper metal eutectic solvent-modified biochar catalyst, comprising the following steps: Biomass raw materials are mixed with acid solution, impregnated and activated, and then pre-carbonized to obtain unmodified biochar; the unmodified biochar is mixed with copper metal eutectic solvent and carbonized at high temperature to obtain copper metal eutectic solvent modified biochar catalyst (i.e., copper-doped modified biochar).

[0007] This invention utilizes a novel copper eutectic solvent as a modifier, achieving copper doping of biochar simultaneously in a single high-temperature carbonization process, eliminating the need for multiple steps. Compared to traditional multi-step impregnation-carbonization methods, this process is significantly simplified, resulting in a highly efficient and convenient preparation method. Furthermore, the copper eutectic solvent exhibits excellent dispersibility, promotes the formation of new functional groups on the biochar surface, and is cost-effective. It effectively loads copper nanoparticles, further modifies the biochar surface, enhances the catalytic activity of the biochar, and significantly reduces preparation costs.

[0008] Furthermore, the acid solution includes a phosphoric acid (H3PO4) solution.

[0009] Activation with phosphoric acid solution can introduce heteroatoms P into the catalyst, thereby adjusting the electron density of the carbon skeleton, increasing surface defects, and enhancing the adsorption and activation capacity of persulfate.

[0010] Furthermore, the biomass raw material includes poplar wood chips.

[0011] Furthermore, the concentration of the phosphoric acid solution is 10-50 wt%, preferably 28.8 wt%.

[0012] Furthermore, before mixing the biomass raw materials with the acid solution, the process further includes drying, pulverizing, and sieving the biomass raw materials.

[0013] Furthermore, the mass ratio of the biomass raw material (dried, pulverized, and sieved biomass raw material) to the acid solution is 1:1.5-2.5.

[0014] Furthermore, the immersion activation time is 2 hours.

[0015] Furthermore, the impregnation activation is carried out under stirring conditions at room temperature (20-30°C).

[0016] Furthermore, the impregnation and activation process also includes a drying step.

[0017] Furthermore, the pre-carbonization temperature is 300-800℃, and the time is 1-4 hours.

[0018] More preferably, the pre-carbonization temperature is 411°C and the time is 128 minutes.

[0019] Furthermore, the heating rate for pre-carbonization is 5°C / min.

[0020] Furthermore, the pre-carbonization is carried out under an inert atmosphere or vacuum conditions.

[0021] Furthermore, after the pre-carbonization is completed, the process also includes steps of cooling, grinding, sieving, washing, and drying.

[0022] Furthermore, the copper eutectic solvent is prepared from copper chloride (CuCl2) and ethylene glycol (EG). The transition metal copper provides the active component.

[0023] Furthermore, the molar ratio of copper chloride to ethylene glycol is 1:4.

[0024] Furthermore, the preparation steps of the copper metal eutectic solvent (referred to as CuCl2-EG) include: mixing copper chloride with ethylene glycol, heating and stirring at 80-100°C until a homogeneous solution is obtained, and then letting it stand for 24 hours.

[0025] Furthermore, the mass ratio of the unmodified biochar to the copper eutectic solvent is 1:3-6, preferably 1:5.

[0026] Furthermore, the process prior to high-temperature carbonization also includes a stirring step.

[0027] Furthermore, the high-temperature carbonization is carried out at a temperature of 600-800℃ for 2 hours. During the high-temperature carbonization process, the copper metal eutectic solvent gradually decomposes, and the CuCl2 intermediate is further transformed into copper-based nanoparticles embedded in the porous structure of the biochar.

[0028] More preferably, the high-temperature carbonization temperature is 800°C.

[0029] Furthermore, the heating rate for the high-temperature carbonization is 5°C / min.

[0030] Furthermore, the high-temperature carbonization is carried out under an inert atmosphere.

[0031] The second technical solution of the present invention: a copper metal eutectic solvent modified biochar catalyst prepared by the above-described method.

[0032] The third technical solution of the present invention: the application of the above-mentioned copper metal eutectic solvent modified biochar catalyst in the activated persulfate degradation of ATZ.

[0033] Furthermore, the application steps include: adding the copper metal eutectic solvent-modified biochar catalyst and persulfate to wastewater containing ATZ pollutants to carry out a degradation reaction.

[0034] Furthermore, the persulfate includes sodium persulfate.

[0035] Furthermore, the amount of the copper metal eutectic solvent modified biochar catalyst added to the wastewater containing ATZ pollutants is 0.2 mg / mL, the amount of persulfate added to the wastewater containing ATZ pollutants is 0.25 mM, and the concentration of ATZ in the wastewater containing ATZ pollutants is 10 mg / L.

[0036] The copper-based eutectic solvent-modified biochar catalyst of this invention can degrade over 99.75% of ATZ within 60 minutes by activating persulfate. Common anions have almost no effect on the degradation process, and the degradation rate in actual aquatic environments remains at 64.18%, still reaching 70.69% after five reuses. Mass spectrometry analysis of the ATZ change process and ecostructure-activity relationship model assessment show that the predicted aquatic toxicity of the detected intermediate products gradually decreases below that of ATZ. It has promising prospects for practical application.

[0037] The present invention discloses the following technical effects: (1) This invention uses a copper eutectic solvent (i.e., a eutectic solvent containing copper metal elements) as a modifier, and simultaneously achieves copper doping of biochar in a single high-temperature carbonization process, without the need for multiple steps. Compared with the traditional multi-step impregnation-carbonization method, this process is greatly simplified and the preparation process is efficient and convenient.

[0038] (2) This invention uses waste biomass such as waste poplar wood as raw materials, which has the advantages of readily available raw materials and low cost, realizing the recycling of waste and having environmental significance.

[0039] (3) The modified biochar catalyst obtained by the present invention through modification with a copper eutectic solvent exhibits significantly better activation and degradation performance of persulfate than unmodified biochar and traditional metal salt-modified biochar. The Cu-BC-800-5 catalyst can achieve an ATZ removal rate of over 99.75% within 60 minutes under relatively mild conditions (~25℃, pH≈7). The catalyst of the present invention demonstrates significantly improved catalytic efficiency in ATZ degradation.

[0040] (4) The Cu-BC-800-5 catalyst of the present invention exhibits excellent adaptability under different water chemistry conditions. When common anions (such as Cl-, SO42-, HPO42-, HCO3-) are present in the water, the degradation effect of ATZ is almost unaffected. Within a wide range of initial pH from acidic to near neutral (approximately 3-7), the catalyst can effectively activate persulfate to degrade ATZ, demonstrating good pH tolerance. At the same time, the degradation rate of the catalyst in actual water environments still reaches 64.18%. In addition, the catalyst has outstanding stability and reusability. Experiments show that after five consecutive cycles of use, the ATZ degradation rate of the Cu-BC-800-5 catalyst still remains at 70.69%, demonstrating good recycling performance.

[0041] (5) Mass spectrometry analysis of the ATZ change process and the evaluation of the ecological structure-activity relationship model showed that the predicted aquatic toxicity of the detected intermediate products gradually decreased below that of the ATZ. It has good prospects for practical application.

[0042] In summary, the copper-doped modified biochar catalyst (especially the Cu-BC-800-5 catalyst) provided by this invention combines ease of preparation with excellent functionality, and can efficiently and sustainably remove ATZ from water, showing promising prospects for practical application. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 The images are SEM images of BC in Example 1 and Cu-BC-800-5 in Example 5. (a) and (b) show the morphology of BC at magnifications of 50,000x and 100,000x, respectively, and (c) and (d) show the morphology of Cu-BC-800-5 at magnifications of 50,000x and 100,000x, respectively.

[0045] Figure 2 X-ray diffraction (a) and Raman spectra (b) of Cu-BC-TX catalyst samples prepared for Examples 1-3 and Example 5.

[0046] Figure 3 Examples 1-6 and Comparative Examples 1-2 show several catalysts (modified BC) prepared and their degradation effect on ATZ. (a) shows the effect of high-temperature carbonization temperature on the degradation of ATZ by catalytic activation of sodium persulfate, (b) shows the effect of the amount of copper metal eutectic solvent added on the degradation of ATZ by catalytic activation of sodium persulfate, and (c) shows the effect of copper introduction method and whether acid activation is performed on the degradation of ATZ by catalytic activation of sodium persulfate.

[0047] Figure 4 The effects of different sodium persulfate concentrations and different catalyst addition amounts on the degradation of ATZ by Cu-BC-800-5 activated sodium persulfate were investigated. (a) shows the effect of sodium persulfate concentration, and (b) shows the effect of catalyst addition amount.

[0048] Figure 5 The effect of coexisting inorganic anions on the degradation performance of ATZ by Cu-BC-800-5 activated sodium persulfate was investigated. (a) shows the effect of each anion concentration at 10 mM, and (b) shows the effect of each anion concentration at 20 mM.

[0049] Figure 6 The effect of different pH values ​​on the degradation performance of ATZ by Cu-BC-800-5 activated sodium persulfate.

[0050] Figure 7 The effect of different water systems on the degradation performance of ATZ by Cu-BC-800-5 activated sodium persulfate.

[0051] Figure 8The results show the reusability test results of the Cu-BC-800-5 catalyst.

[0052] Figure 9 The effect of free radical quenchers on the degradation of ATZ in the Cu-BC-800-5 / PDS system.

[0053] Figure 10 The results are EPR characterizations, where (a) is DMPO-SO4· - EPR plots of DMPO-·OH, (b) for DMPO-O2· - The EPR diagram, (c) is TEMP- 1 EPR graph of O2.

[0054] Figure 11 This is a schematic diagram of the degradation pathway of ATZ.

[0055] Figure 12 The results of the toxicity assessment of ATZ degradation intermediates are shown. (a)-(c) are the results of the acute toxicity assessment of fish, algae and green algae, respectively, and (d)-(f) are the results of the chronic toxicity assessment of fish, algae and green algae, respectively. Detailed Implementation

[0056] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0057] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0058] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0059] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0060] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0061] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0062] As a first aspect of the present invention, the present invention provides a method for preparing a copper eutectic solvent-modified biochar (abbreviated as Cu-BC-TX, where T is the high-temperature carbonization temperature and X is the mass ratio of copper eutectic solvent to unmodified biochar) catalyst, comprising the following steps: (1) The biomass raw material is pretreated by acid immersion activation and then pre-carbonized to obtain unmodified biochar. The specific steps are as follows: After crushing and sieving the biomass raw material, it is mixed evenly with a 10-50wt% phosphoric acid solution (preferably a 28.8wt% phosphoric acid solution). The mixture is immersed and activated at room temperature for 2 hours with stirring to allow the acid solution to fully penetrate the biomass raw material. The activated biomass raw material is heated to 300-800℃ (preferably a carbonization temperature of 411℃) at a heating rate of 5℃ / min under an inert atmosphere or vacuum. It is then pre-carbonized at a constant temperature for 1-4 hours (preferably a carbonization time of 128 minutes). After pre-carbonization, the product is cooled and taken out. It is then ground through a 200-mesh sieve and then washed alternately with acid solution (preferably a 1mol / L hydrochloric acid solution) and deionized water until the filtrate is close to neutral to remove residual inorganic salts and impurities. Finally, it is dried at 70-80℃ to obtain unmodified biochar (abbreviated as BC). (2) Anhydrous copper chloride and ethylene glycol are mixed at a molar ratio of 1:4 and stirred in an oil bath at 80-100℃ until a homogeneous solution is obtained; then the solution is allowed to stand at room temperature for 24 hours to ensure that the solution remains homogeneous, indicating that the copper metal eutectic solvent (copper chloride-ethylene glycol eutectic solvent, abbreviated as CuCl2-EG) has been successfully prepared. (3) Take the unmodified biochar obtained in step (1) and the copper metal eutectic solvent obtained in step (2) and mix them evenly. Carbonize them at high temperature under inert gas protection to prepare Cu-BC-TX catalyst. In a typical preparation process, unmodified biochar and CuCl2-EG are mixed at a mass ratio of 1:3-6 (preferably 1:5). Stir to make the unmodified biochar fully wetted in the copper metal eutectic solvent. Then, under nitrogen protection, the mixture is heated to 600-800℃ (preferably 800℃) at a heating rate of 5℃ / min. It is then carbonized at this temperature for 2 hours and then cooled to obtain Cu-BC-TX (i.e., copper-doped modified biochar) catalyst.

[0063] During the high-temperature carbonization process, CuCl2 in the CuCl2-EG eutectic solvent is further transformed into copper-based nanoparticles embedded in the porous structure of biochar. This novel solvent achieves copper doping of biochar in a single high-temperature carbonization process, eliminating the need for multiple steps. Compared to traditional multi-step impregnation-carbonization methods, this process is significantly simplified, making the preparation highly efficient and convenient.

[0064] As a second aspect of the present invention, the present invention also provides a copper metal eutectic solvent modified biochar catalyst prepared by the preparation method of the copper metal eutectic solvent modified biochar catalyst described above.

[0065] In a preferred embodiment of the present invention, the copper metal eutectic solvent modified biochar catalyst is a Cu-BC-800-5 catalyst.

[0066] As a third aspect of the present invention, the present invention also provides the application of the above-mentioned copper metal eutectic solvent modified biochar catalyst in the activated persulfate degradation of ATZ.

[0067] This invention utilizes copper-based eutectic solvent-modified biochar catalysts (such as Cu-BC-800-5 catalyst) for the activation of persulfate (preferably sodium peroxydisulfate (Na2S2O8, PDS)), enabling efficient degradation of ATZ in water. For example, adding a certain dose of Cu-BC-800-5 catalyst and persulfate to ATZ-containing wastewater activates the persulfate on the catalyst surface, generating highly oxidizing sulfate radicals and hydroxyl radicals, which attack and decompose ATZ molecules. Preferably, under conditions of 10 mg / L pollutant concentration, 0.25 mM persulfate concentration, 0.2 mg / mL catalyst dosage, and near-neutral pH, 99.75% degradation and removal of ATZ can be achieved in a short time.

[0068] In a specific embodiment of the present invention, the copper-based nanoparticles contained in the Cu-BC-800-5 catalyst serve as a transition metal component, which can cyclically activate persulfates (such as PDS) to generate highly oxidizing sulfate radicals (SO4·4·5). - Phosphorus-containing functional groups introduced into the Cu-BC-800-5 catalyst can regulate the electron density of the carbon skeleton, increase surface defects, and enhance the adsorption and activation capacity for persulfate. Furthermore, the well-developed porous structure formed by acid activation and high-temperature carbonization during the preparation of the Cu-BC-800-5 catalyst can enhance the contact efficiency between ATZ molecules and the active sites on the catalyst surface, accelerating the degradation reaction. The synergistic effect of these three factors enables the catalyst to achieve a 99.75% degradation rate of ATZ within 60 minutes under mild conditions (~25℃, pH≈7), far superior to unmodified biochar and traditional CuCl2-modified biochar.

[0069] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0070] Unless otherwise specified, the room temperature mentioned in the following examples, comparative examples, test examples and application examples refers to 20-30°C.

[0071] Unless otherwise specified, the experimental methods used in the following examples, comparative examples, test examples, and application examples are conventional methods; and the reagents, materials, and equipment used are commercially available unless otherwise specified.

[0072] Example 1 A method for preparing a Cu-BC-TX catalyst includes the following steps: (1) Poplar sawdust waste was selected as biomass raw material. The biomass raw material was dried, crushed, and passed through a 200-mesh sieve to obtain fine powder. 50g of poplar sawdust fine powder was weighed and 100g of 28.8wt% H3PO4 solution was added. The mixture was stirred and impregnated at room temperature for 2 hours to allow the acid solution to fully penetrate the pores of the biomass raw material. After impregnation, the sample was dried in a vacuum drying oven at 80℃ for 12 hours. Then, the dried acid-treated biomass was placed in a tube furnace and heated to 411℃ at a rate of 5℃ / min under a high-purity nitrogen atmosphere. It was then pre-carbonized at 411℃ for 128 minutes. After the pre-carbonization was completed, the heating was turned off and the furnace was allowed to cool naturally to room temperature. The carbonized product was then removed to obtain unmodified biochar. The unmodified biochar was ground and passed through a 200-mesh sieve. Then, it was washed several times with alternating 1mol / L hydrochloric acid solution and deionized water until the filtrate was close to neutral to remove residual inorganic matter and impurities. Finally, the product was dried in a vacuum drying oven at 70°C for 12 hours to obtain clean and dry unmodified biochar (denoted as BC).

[0073] (2) Anhydrous copper chloride and ethylene glycol are mixed at a molar ratio of 1:4 and stirred in an oil bath at 80°C until a homogeneous solution is obtained. Then, the solution is allowed to stand at room temperature for 24 hours to ensure that it remains homogeneous, indicating that the eutectic solvent for copper metal has been successfully prepared, and is denoted as CuCl2-EG.

[0074] (3) Mix 10g of BC obtained in step (1) with 30g of CuCl2-EG obtained in step (2) (the mass ratio of BC to CuCl2-EG is 1:3, just enough to submerge the BC). Stir the unmodified biochar to fully impregnate it in the copper metal eutectic solvent. Then place the mixture in a tube furnace under nitrogen protection and heat it to 800°C at a heating rate of 5°C / min. Carbonize it at 800°C for 2 hours. During the high-temperature carbonization process, the eutectic solvent CuCl2-EG decomposes and releases the active components. The CuCl2 intermediate is further converted into copper nanoparticles and embedded in the pore structure of the biochar. After carbonization is completed, stop heating and take out the product after the furnace body cools to room temperature. The Cu-BC-TX catalyst (i.e., copper-doped modified biochar) is obtained and is denoted as Cu-BC-800-3. Store it in a desiccator for later use.

[0075] Example 2 Same as Example 1, except that in step (3), the temperature is increased to 600°C at a rate of 5°C / min, and carbonized at 600°C for 2 hours. The resulting catalyst is named Cu-BC-600-3 and stored in a desiccator for later use.

[0076] Example 3 Same as Example 1, except that in step (3), the temperature is increased to 700°C at a rate of 5°C / min, and carbonized at 700°C for 2 hours. The resulting catalyst is named Cu-BC-700-3 and stored in a desiccator for later use.

[0077] Example 4 Same as Example 1, except that in step (3), the mass ratio of BC to CuCl2-EG is 1:4 (10g:40g), and the final catalyst is recorded as Cu-BC-800-4 and stored in a desiccator for later use.

[0078] Example 5 Same as Example 1, except that in step (3), the mass ratio of BC to CuCl2-EG is 1:5 (10g:50g), and the final catalyst is recorded as Cu-BC-800-5 and stored in a desiccator for later use.

[0079] Example 6 Same as Example 1, except that in step (2), BC and CuC l2The mass ratio of -EG is 1:6, and the resulting catalyst is denoted as Cu-BC-800-6 and stored in a desiccator for later use.

[0080] Comparative Example 1 Same as Example 5, except that CuCl2-EG was replaced with a 35.31wt% CuCl2 aqueous solution (the molar amount of Cu in the CuCl2 aqueous solution was the same as the molar amount of Cu in 50g CuCl2-EG). Then, the mixture of BC and CuCl2 aqueous solution was placed in a tube furnace under nitrogen protection and heated to 800°C at a rate of 5°C / min. It was then carbonized at 800°C for 2 hours. The final product was CuCl2 modified biochar, denoted as CuCl2-BC, and stored in a desiccator for later use.

[0081] Comparative Example 2 Same as Example 5, except that the process of soaking the biomass raw material in H3PO4 solution is omitted in step (1). The specific operation is adjusted as follows: Poplar sawdust waste is selected as biomass raw material. The biomass raw material is dried and crushed, and then passed through a 200-mesh sieve to obtain fine powder. 50g of poplar sawdust fine powder is weighed and dried in a vacuum drying oven at 80℃ for 12 hours. Then it is placed in a tube furnace and heated to 411℃ at a rate of 5℃ / min under a high-purity nitrogen atmosphere. It is then pre-carbonized at 411℃ for 128 minutes. Then it is ground and passed through a 200-mesh sieve. Subsequently, it is washed multiple times with 1mol / L hydrochloric acid solution and deionized water alternately until the filtrate is close to neutral. Finally, it is dried in a vacuum drying oven at 70℃ for 12 hours to obtain clean and dry unmodified biochar (denoted as PBC). Steps (2)-(3) are the same as in Example 5. The catalyst obtained is denoted as Cu-PBC-800-5 and stored in a desiccator for later use.

[0082] Morphological, structural, and compositional characteristics Figure 1 Scanning electron microscope (SEM) images of unmodified biochar (BC) in Example 1 and copper-doped modified biochar (Cu-BC-800-5) in Example 5 are shown. (a) and (b) show the morphology of BC at 50,000x and 100,000x magnification, respectively; (c) and (d) show the morphology of Cu-BC-800-5 at 50,000x and 100,000x magnification, respectively. The comparison shows that the surface of unmodified biochar BC is relatively smooth and dense, with an underdeveloped pore structure. In contrast, the Cu-BC-800-5 sample exhibits a porous carbon structure with significantly increased surface pores and fragmented structures. This is because the decomposition of the added copper eutectic solvent at high temperatures excites and etches the carbon framework, generating additional pores. Furthermore, from... Figure 1The comparison at different magnifications shows that fine particles are attached to the surface of biochar in the Cu-BC-800-5 sample. Energy dispersive spectroscopy analysis confirmed that these particles contain copper, indicating that copper is embedded in the biochar channels in the form of nanoparticles.

[0083] Figure 2 Figure (a) shows the X-ray diffraction patterns of the Cu-BC-TX catalyst samples prepared in Examples 1-3 and Example 5, as well as the X-ray diffraction patterns of BC. It can be seen that the XRD patterns of the BC and Cu-BC-600-3 samples show only one broad, diffuse peak near 2θ≈23°, corresponding to the reflection from the (002) plane of amorphous carbon. This may be because the copper on the surface of Cu-BC-600-3 exists in an amorphous form, or because the copper content is low, resulting in an indistinct diffraction signal. In contrast, Cu-BC-700-3, Cu-BC-800-3, and Cu-BC-800-5, in addition to retaining the broad peak from the (002) plane of carbon, show new diffraction peaks, which correspond to Cu3P, Cu2O, and Cu, respectively. 0 This indicates that copper exists primarily in these forms in the modified biochar. Figure 2 (b) shows the Raman spectra of the Cu-BC-TX catalyst samples prepared in Examples 1-3 and 5, and BC (Cu-BC-800-1-5 in the figure is equivalent to Cu-BC-800-5). The spectra are at approximately 1340 cm⁻¹. -1 and 1580 cm -1 At these locations, all samples exhibited D and G peaks, corresponding to the defect / disorder structure of carbon materials and the vibrational modes of the graphite carbon framework, respectively. Compared to BC, the D / G peak intensity ratios of Cu-BC-600-3, Cu-BC-700-3, Cu-BC-800-3, and Cu-BC-800-5 samples were significantly increased. This indicates that the degree of defect on the biochar surface is improved after copper doping modification. The increase in the ID / IG ratio is related to the incorporation of more heteroatoms and lattice distortion, suggesting that Cu doping in the eutectic solvent of copper metal introduces additional defects and edge sites into the carbon framework, and these defect sites are conducive to the activation of persulfate.

[0084] Application Example 1 Performance testing of ATZ degradation by catalyst-activated sodium persulfate (PDS) The degradation conditions were as follows: ATZ was added to 100 mL of distilled water to achieve a solution concentration of 10 mg / L (pH ≈ 7, no additional adjustment), and the temperature was 25 °C. 10 mg of catalyst (the catalyst prepared in each example or comparative example, and BC) was added, followed by PDS to achieve a concentration of 0.25 mM. The solution was shaken at 180 r / min in a constant temperature (25 °C) shaker. Samples were taken every 0-60 minutes, filtered through a 0.22 μm aqueous filter membrane, and the ATZ concentration was determined by LC-MS / MS to calculate the degradation rate. Each experiment was repeated three times, and the average value was taken. The degradation effects of several catalysts (modified BC) prepared in Examples 1-6 and Comparative Examples 1-2 on ATZ are shown in [reference needed]. Figure 3 (a) Figure 3 (b) and Figure 3 (c)

[0085] Figure 3 Figure (a) shows the effect of high-temperature carbonization temperature on the degradation of ATZ by sodium persulfate activated by the catalyst. The results show that the total degradation rate after 60 minutes with the addition of unmodified biochar (BC) is approximately 59.21%, indicating that BC itself has limited activation ability for PDS. In contrast, the samples doped with copper exhibit higher catalytic activity: the degradation rates of the Cu-BC-600-3, Cu-BC-700-3, and Cu-BC-800-3 catalyst systems after 60 minutes are approximately 60.78%, 64.21%, and 72.34%, respectively, indicating that the introduction of copper provides certain activity. It can also be seen that the degradation rate gradually increases with increasing temperature, indicating that increasing the temperature leads to more complete pyrolysis of the biochar, more Cu-containing microparticles, and better removal effect.

[0086] Figure 3 Figure (b) shows the effect of the amount of copper eutectic solvent added on the degradation of ATZ by sodium persulfate activated by the catalyst. The results show that with the increase of the amount of copper eutectic solvent added, the degradation first increases and then decreases. The degradation rates of the Cu-BC-800-3, Cu-BC-800-4, Cu-BC-800-5 and Cu-BC-800-6 catalyst systems after 60 minutes are approximately 72.34%, 78.21%, 82.56% and 74.19%, respectively. This indicates that the more copper is added, the higher the catalytic activity of biochar. However, if copper is excessive, too many Cu-containing microparticles will agglomerate, "covering" the active sites or blocking the pores, resulting in a decrease in activity.

[0087] Figure 3Figure (c) illustrates the effect of copper introduction method and acid activation on the degradation of ATZ by activated sodium disulfate. The results show that CuCl2-EG modified biochar exhibits significantly better degradation performance for ATZ than traditional CuCl2 modified biochar (degradation rate approximately 60.56%), and also outperforms the catalyst directly loaded with copper without phosphoric acid modification (degradation rate approximately 23.57%). This indicates that the eutectic solvent possesses good dispersibility and low cost advantages, effectively loading copper ions to improve the catalytic activity of biochar.

[0088] Application Example 2 Effects of different persulfate concentrations and different catalyst additions on the degradation of ATZ by Cu-BC-800-5 activated sodium persulfate (PDS) The degradation conditions were as follows: ATZ was added to 100 mL of distilled water to achieve a solution concentration of 10 mg / L (pH ≈ 7, no additional adjustment), and the temperature was 25 °C. 10-20 mg of the Cu-BC-800-5 catalyst prepared in Example 5 was added, followed by PDS to achieve a concentration of 0.1-0.75 mM. The solution was shaken at 180 r / min in a constant temperature (25 °C) shaker. Samples were taken every 0-60 minutes, filtered through a 0.22 μm aqueous filter, and the ATZ concentration was determined by LC-MS / MS to calculate the degradation rate. Each experiment was repeated three times, and the average value was taken. The effects of different persulfate concentrations and different catalyst addition amounts on the degradation of ATZ by Cu-quBC-800-5 activated sodium persulfate are as follows: Figure 4 (a) and Figure 4 As shown in (b).

[0089] Figure 4 Figure (a) shows the effect of sodium persulfate concentration on the degradation of ATZ by Cu-BC-800-5 activated sodium persulfate (catalyst addition was fixed at 10 mg). The results indicate that the removal rate of ATZ increased when the sodium persulfate concentration increased from 0.1 mM to 0.25 mM. Further increasing the persulfate concentration may lead to the formation of persulfate by sulfate radicals, thereby reducing the attack on ATZ and decreasing the removal efficiency.

[0090] Figure 4 Figure (b) shows the effect of catalyst addition on the degradation of ATZ by Cu-BC-800-5 activated sodium persulfate (sodium persulfate concentration fixed at 0.25 mM). The results show that when the Cu-BC-800-5 catalyst addition increased from 10 mg to 20 mg, the ATZ removal rate increased (to 99.75%). This indicates that the ATZ removal rate increases with increasing catalyst dosage.

[0091] Application Example 3 Effects of different environmental factors on the degradation of ATZ by Cu-BC-800-5 activated sodium persulfate (PDS) Considering the complexity of real-world aquatic environments, this application example examines the effects of coexisting inorganic anions, solution pH, and different water systems on the degradation performance of modified biochar of ATZ, in order to reflect the influence of the solution chemical environment on the adsorption process.

[0092] (I) Effect of inorganic anions on the degradation of ATZ by Cu-BC-800-5 activated sodium persulfate The degradation conditions were as follows: ATZ was added to 100 mL of distilled water to achieve a solution concentration of 10 mg / L (pH ≈ 7, no additional adjustment), and the temperature was 25 °C. Metal salts containing different inorganic anions (NaCl, NaHCO3, Na2SO4, and Na2HPO4) were added, followed by 20 mg of the Cu-BC-800-5 catalyst prepared in Example 5 (i.e., catalyst concentration of 0.2 mg / mL). PDS was then added to achieve a concentration of 0.25 mM in the solution. The solution was shaken at 180 r / min in a constant temperature (25 °C) shaker. Samples were taken at regular intervals from 0 to 60 minutes, filtered through a 0.22 μm aqueous filter membrane, and the ATZ concentration was determined by LC-MS / MS to calculate the degradation rate. Each experiment was repeated three times, and the average value was taken. The effect of coexisting inorganic anions on the ATZ degradation performance of Cu-BC-800-5 activated sodium persulfate is shown in [the table below]. Figure 5 (a) and Figure 5 (b)

[0093] like Figure 5 As shown in (a), in the presence of 10 mM NaCl (providing Cl), - ), 10mM Na2SO4 (providing SO4) 2- ), 10mM NaHCO3 (providing HCO3) - ) and 10mM Na2HPO4 (providing HPO4) 2- Under the conditions of ), the ATZ degradation rate did not change significantly within 60 minutes compared with the time without interference.

[0094] like Figure 5 As shown in (b), in a solution containing 20 mM Na2SO4 (providing SO42-), 2- Under these conditions, the ATZ degradation rate showed no significant change within 60 minutes compared to the undisturbed state. This indicates that SO42- 2- Anion pair S2O8 2- The system is minimally affected. In a system containing 20 mM NaCl (providing Cl₂), - ), 20mM NaHCO3 (providing HCO3) - ) and 20mM Na2HPO4 (providing HPO4)2- Under these conditions, the ATZ degradation rate decreased slightly (to about 80%), but still remained at a high level.

[0095] (II) Effect of solution pH on the degradation of ATZ by Cu-BC-800-5 activated sodium persulfate The degradation conditions were as follows: ATZ was added to 100 mL of distilled water to achieve a solution concentration of 10 mg / L, the temperature was 25 °C, and the pH of the solution was adjusted to 3-11. Then, 20 mg of the Cu-BC-800-5 catalyst prepared in Example 5 was added, followed by PDS to achieve a concentration of 0.25 mM in the solution. The mixture was shaken at 180 r / min in a constant temperature shaker (25 °C), and samples were taken at regular intervals from 0 to 60 minutes. After passing through a 0.22 μm aqueous filter membrane, the ATZ concentration was determined by LC-MS / MS, and the degradation rate was calculated. Each experiment was repeated three times, and the average value was taken. Figure 6 As shown.

[0096] like Figure 6 The figure shows the trend of ATZ degradation rate of Cu-BC-800-5 within the pH range of 3-11. It can be seen that the degradation rate gradually increases from acidic to neutral, reaching its maximum at pH≈7 (Control, i.e., no additional adjustment), and then significantly decreases under alkaline conditions. Therefore, the optimal degradation effect of the catalyst of this invention occurs near neutrality, which is of great significance for practical applications, as environmental water bodies are often neutral to slightly alkaline.

[0097] (III) Effects of different water systems on the degradation of ATZ by Cu-BC-800-5 activated sodium persulfate The degradation conditions were as follows: ATZ was added to 100 mL of distilled water, tap water, and river water respectively, to achieve a solution concentration of 10 mg / L (pH not adjusted). The temperature was 25 °C. 20 mg of the Cu-BC-800-5 catalyst prepared in Example 5 was added, followed by PDS to achieve a concentration of 0.25 mM. The solution was shaken at 180 r / min in a constant temperature (25 °C) shaker. Samples were taken at regular intervals from 0 to 60 minutes. After passing through a 0.22 μm aqueous filter membrane, the ATZ concentration was determined by LC-MS / MS, and the degradation rate was calculated. Each experiment was repeated three times, and the average value was taken. The results of ATZ degradation by Cu-BC-800-5 activated sodium persulfate in different water systems are as follows: Figure 7 As shown.

[0098] like Figure 7The degradation rates of ATZ by Cu-BC-800-5 activated sodium persulfate in different water systems are shown. It can be seen that compared to the degradation rate in distilled water, the degradation rates in tap water and river water are lower, with ATZ degradation rates of 74.39% and 64.18%, respectively. However, these rates still maintain a high removal rate, indicating that the catalyst has good degradation performance in practical applications.

[0099] Application Example 4 Reusability test of Cu-BC-800-5 catalyst The degradation conditions were as follows: ATZ was added to 100 mL of distilled water to achieve a solution concentration of 10 mg / L (pH ≈ 7, no additional adjustment), and the temperature was 25 °C. 20 mg of catalyst (Cu-BC-800-5) was added, followed by PDS to achieve a concentration of 0.25 mM. The reaction was carried out in a constant-temperature (25 °C) shaker at 180 r / min. After each reaction lasted 60 minutes, the catalyst was collected, the solid was separated by centrifugation, and gently washed with acetonitrile and deionized water. New ATZ solution and PDS were then added to begin the next cycle. This process was repeated for 5 cycles, and the ATZ removal rate was recorded at the end of each cycle. The results are shown below. Figure 8 As shown.

[0100] like Figure 8 As shown, the Cu-BC-800-5 catalyst maintained high catalytic activity during repeated use: the ATZ degradation rate was 99.75% in the first cycle and approximately 70.69% after the fifth cycle. This demonstrates that the catalyst of the present invention has good stability and reusability.

[0101] Application Example 5 Recognition of active species in the Cu-BC-800-5 activated sodium persulfate (PDS) degradation ATZ system This application example demonstrates free radical quenching experiments and electron paramagnetic resonance (EPR) detection on Cu-BC-800-5, with the basic reaction conditions remaining consistent with Application Example 4. The effect of the free radical quencher on the degradation of ATZ in the Cu-BC-800-5 / PDS system was specifically investigated by adding different quenchers (200 mM methanol (MeOH), SO4· ... - 200 mM tert-butanol (TBA, quenching ·OH), 20 mM p-benzoquinone (p-BQ, quenching) 1 O2), 20 mM furfuryl alcohol (FFA, quenching O2· - The degradation of ATZ in the Cu-BC-800-5 / PDS system was investigated, and the type of active substance was inferred by the effect of adding a free radical quencher on the degradation rate. The effect of the free radical quencher on the degradation of ATZ in the Cu-BC-800-5 / PDS system is as follows: Figure 9 As shown (Contral represents the control group without added free radical quenchers), the results indicate that all four reagents have a certain quenching effect. The quenching effect of the four reagents on degradation is: p-BQ > FFA > TBA > MeOH, indicating that... 1 O2 is the main oxide species in the degradation process.

[0102] To further directly observe the generation of reactive free radicals, this application example also utilized spin trapping technology combined with EPR to test the reaction solution after Cu-BC-800-5 was added to PDS solution and reacted, SO4· - ·OH and O2· - Captured via 5,5-dimethyl-1-pyrrololine-N-oxide (DMPO) 1 O2 was captured using 2,2,6,6-tetramethylpiperidine (TEMP). Before the test, Cu-BC-800-5 was added to a sodium persulfate solution at a concentration of 0.25 mM, and the amount of Cu-BC-800-5 added was 0.02 g / L. A sodium persulfate solution without Cu-BC-800-5 was used as a blank control. Samples were taken at 2 and 10 minutes of the reaction. For SO4· - ·OH and O2· - Take 50 μL of the reaction solution, add 50 μL of methanol and 100 μL of 100 mM DMPO solution, mix well, fill and seal the sample tube using a capillary tube, then place it in the sample tube and put it into the instrument for testing and data acquisition; for 1 For O2, add 100 μL of the reaction solution to 100 μL of 100 mM TEMP solution, mix well, fill and seal the sample via a capillary tube, and then place it in the sample tube for instrument testing and data acquisition. The electron paramagnetic resonance (EPR) spectrum for detecting active free radicals is shown below. Figure 10 , where (a) is DMPO-SO4· - EPR plots of DMPO-·OH, (b) for DMPO-O2· - The EPR diagram, (c) is TEMP- 1 The EPR spectrum of O2 shows that a typical free radical capture signal appeared in the reaction solution containing catalyst + PDS + DMPO / TEMP, while no significant signal was observed in the control group without catalyst.

[0103] Application Example 6 Toxicity assessment of ATZ degradation products from Cu-BC-800-5 This application example demonstrates the detection of degradation products of Cu-BC-800-5. The basic reaction conditions were consistent with Application Example 4, and samples were taken at 0 min, 5 min, 15 min, 30 min, and 60 min for mass spectrometry analysis. Mass spectrometry analysis of the ATZ changes revealed the degradation products to be P1-P8, and the degradation pathway is as follows: Figure 11 As shown. The toxicity of degradation products was assessed using an ecostructure-activity relationship model. The results are as follows. Figure 12 As shown, (a)-(c) represent the acute toxicity assessment results for fish, aquatic algae, and green algae, respectively, while (d)-(f) represent the chronic toxicity assessment results for fish, aquatic algae, and green algae, respectively. It can be seen that the predicted aquatic toxicity of the detected intermediate products gradually decreases below that of the ATZ (Acute Toxicity of the Algae).

[0104] In summary, this invention achieves the preparation of a copper-doped modified biochar catalyst that is simple to prepare and has a significant modification effect by using a copper eutectic solvent to modify biochar. This overcomes the shortcomings of traditional modification methods and exhibits excellent persulfate activation performance, broad environmental adaptability, and good cycle stability, which is of great value for the treatment of ATZ polluted wastewater.

[0105] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a copper metal eutectic solvent-modified biochar catalyst, characterized in that, Includes the following steps: Biomass feedstock is mixed with acid solution, impregnated and activated, and then pre-carbonized to obtain unmodified biochar; the unmodified biochar is mixed with copper eutectic solvent and carbonized at high temperature to obtain copper eutectic solvent modified biochar catalyst.

2. The preparation method of the copper metal eutectic solvent modified biochar catalyst as described in claim 1, characterized in that, The acid solution includes a phosphoric acid solution.

3. The preparation method of the copper metal eutectic solvent modified biochar catalyst as described in claim 2, characterized in that, The concentration of the phosphoric acid solution is 10-50 wt%; And / or, the impregnation activation time is 2 hours.

4. The method for preparing the copper metal eutectic solvent-modified biochar catalyst as described in claim 1, characterized in that, The pre-carbonization temperature is 300-800℃, and the time is 1-4 hours.

5. The method for preparing the copper metal eutectic solvent-modified biochar catalyst as described in claim 1, characterized in that, The copper eutectic solvent is prepared from copper chloride and ethylene glycol.

6. The method for preparing the copper metal eutectic solvent-modified biochar catalyst as described in claim 5, characterized in that, The molar ratio of copper chloride to ethylene glycol is 1:

4.

7. The method for preparing the copper metal eutectic solvent-modified biochar catalyst as described in claim 1, characterized in that, The mass ratio of the unmodified biochar to the copper eutectic solvent is 1:3-6.

8. The method for preparing the copper metal eutectic solvent-modified biochar catalyst as described in claim 1, characterized in that, The high-temperature carbonization is carried out at a temperature of 600-800℃ for 2 hours.

9. A copper metal eutectic solvent modified biochar catalyst prepared by the method of any one of claims 1-8.

10. The application of a copper metal eutectic solvent modified biochar catalyst as described in claim 9 in the activation of persulfate for atrazine degradation.

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