Modified porous carbon-based composite material, preparation method and application thereof

Abstract

The present invention discloses a modified porous carbon-based composite material, a preparation method and its application in the field of adsorbent preparation technology; the present invention can prepare a porous carbon material with a rich pore structure by compounding an activator component and applying it to the preparation process of the porous carbon material; by infiltrating a sol containing a boron precursor and a titanium precursor into the pores of the porous carbon material and calcining it, boron and titanium dioxide are successfully doped into the pores of the porous carbon material, thereby achieving a modification of the porous carbon material, so that the prepared modified porous carbon-based composite material can enhance its removal performance of metal ions and organic matter in wastewater through the synergistic effect of adsorption and photocatalysis. The present invention has the advantages of simple process, green environmental protection, low cost, etc. The prepared modified porous carbon-based composite material has excellent removal performance for metal ions and organic matter in wastewater, and shows obvious economic value in the field of sewage treatment.

Description

Technical Field

[0001] The present application belongs to the technical field of adsorbent preparation, and in particular relates to a modified porous carbon-based composite material, a preparation method and applications thereof. Background Art

[0002] The chemical industry plays a vital role in modern society. However, its massive production volume also results in the generation of large quantities of wastewater, which contains various organic compounds, heavy metals, and other hazardous substances. This wastewater poses a serious threat to the environment and ecosystems. In recent years, with the increasing awareness of environmental protection and the increasingly stringent environmental regulations, the research and implementation of chemical industry wastewater treatment technologies have become particularly important. The treatment of chemical wastewater involves complex chemical, biological, and physical processes, and its characteristics include the complex diversity of wastewater components, high concentrations of pollutants, and significant harm to the ecological environment.

[0003] At present, adsorption treatment technology is a simple and effective technology for treating industrial wastewater. It is widely used in the treatment of industrial wastewater containing heavy metal ions, dye wastewater, petrochemical wastewater, etc. Common technologies for industrial wastewater treatment include biochar adsorption, zeolite exchange, etc.

[0004] Biochar is a type of insoluble, stable, highly aromatic carbon-rich material formed by the pyrolysis of biomass under oxygen-limited or anaerobic conditions. As an economical and environmentally friendly adsorbent, biochar has been widely used to remove heavy metals from water. However, traditional biochar often has some shortcomings. For example, the original biochar has a small specific surface area, a low content of surface functional groups, and poor adsorption of metal ions. Some modified biochar activators are highly polluting and can cause environmental pollution. In addition, simple adsorption technology may not be ideal for removing pollutants, and sometimes it is necessary to add more adsorbent material to achieve the desired effect.

[0005] Therefore, providing a new modified porous carbon-based composite material to solve the above-mentioned defects is an urgent problem to be solved. Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a modified porous carbon-based composite material, a preparation method and its application; the present invention can prepare a porous carbon material with a rich pore structure by compounding an activator component and applying it to the preparation process of the porous carbon material; at the same time, the present invention successfully dopes boron and titanium dioxide into the pores of the porous carbon material by infiltrating a sol containing a boron precursor and a titanium precursor into the pores of the porous carbon material and calcining it, thereby achieving a modification of the porous carbon material, so that the obtained modified porous carbon-based composite material can enhance its removal performance of metal ions and organic matter in wastewater through the synergistic effect of adsorption and photocatalysis. The present invention has the advantages of simple process, green environmental protection, low cost, etc. At the same time, the obtained modified porous carbon-based composite material has excellent removal performance for metal ions and organic matter in wastewater, and has shown obvious economic value in the field of sewage treatment.

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

[0008] A method for preparing a modified porous carbon-based composite material comprises the following steps:

[0009] S1. Preparation of porous carbon materials:

[0010] S101. The biomass raw material is washed with water and dried, crushed, and sieved to obtain a biomass powder;

[0011] S102. The biomass powder is placed in a porcelain boat in a tube furnace and calcined at 600-700 ° C under a nitrogen atmosphere for 2-3 h to obtain a carbonized powder, labeled AC.

[0012] S103. Weigh 2-3 parts of AC and 2-3 parts of the composite activator in parts by mass, mix and grind the two for 30-40 minutes, and dry the resulting mixture at 80-90 ° C for 10-12 hours;

[0013] S104. The mixture obtained by step S103 is placed in a porcelain boat in a tube furnace and calcined twice under a nitrogen atmosphere at a temperature of 800-900°C for a treatment time of 2-3h.

[0014] S105. The mixture treated in step S4 is removed, cooled to room temperature, washed with hydrochloric acid for 5-6 minutes, then washed with deionized water until neutral, and finally dried at 100-120 ° C to obtain a porous carbon material;

[0015] S2. Preparation of modified porous carbon-based composite materials:

[0016] S201. 1-2 parts by mass of trimethyl borate and 2-4 parts of tetrabutyl titanate are dissolved in 10-20 parts of ethanol and stirred at room temperature for 20-30min to mix thoroughly;

[0017] S202. Aqueous ammonia was added dropwise to the solution obtained in step S201 to control the pH of the solution to 9-11, initiating hydrolysis and polycondensation reactions, and stirring was continued for 1-2 hours to form a transparent sol-like substance;

[0018] S203. The porous carbon material and the sol-like substance obtained in step S202 are mixed uniformly in a mass ratio of 1:5-1:10 and immersed in a vacuum condition for 2-4 hours to promote better penetration of the sol into the pores of the porous carbon material;

[0019] S204. After the impregnation is completed, the sol containing the porous carbon material is allowed to stand at room temperature for 12-18 hours, and then dried at 60-80°C for 12-15 hours;

[0020] S205. calcining the sol containing the porous carbon material processed in step S204 to obtain the modified porous carbon-based composite material.

[0021] Preferably, in step S101, the biomass raw material is one or more of wood chips, pine cones, rice straw, and sugarcane bagasse.

[0022] Preferably, in step S103, the composite activator is a mixture of K2CO3 and NH4Cl in a mass ratio of 0.001-1:1-3.

[0023] Preferably, in step S105, the concentration of hydrochloric acid is 1-2 mol / L.

[0024] Preferably, in step S202, the concentration of the ammonia water is 0.5-1 mol / L.

[0025] Preferably, during the reaction process of step S202, the temperature is maintained at 30-40°C.

[0026] Preferably, in step S203, the vacuum condition is a vacuum degree of 0.05-0.1 MPa.

[0027] Preferably, in step S205, the operating parameters of the calcination treatment are: calcination temperature 400-600°C, calcination time 2-4h, heating rate 5°C / min, and protective gas N2 flow rate 50-80 sccm.

[0028] A modified porous carbon-based composite material is prepared according to the preparation method.

[0029] A modified porous carbon-based composite material prepared according to the preparation method or use of the modified porous carbon-based composite material in wastewater treatment.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention can prepare porous carbon materials with rich pore structures by compounding activator components and applying them to the preparation process of porous carbon materials;

[0032] 2. The present invention successfully dopes boron and titanium dioxide into the pores of the porous carbon material by infiltrating a sol containing a boron precursor and a titanium precursor into the pores of the porous carbon material and calcining the sol. This modifies the porous carbon material, resulting in a more complex pore structure, more surface defects, and richer functional groups. The doping of boron and titanium dioxide also imparts excellent photocatalytic properties to the final material, significantly enhancing its ability to remove pollutants from wastewater through the synergistic effect of adsorption and photocatalysis.

[0033] 2. The present invention has the advantages of simple process, green environmental protection, and low cost. At the same time, the modified porous carbon-based composite material prepared has excellent removal performance for metal ions and organic matter in wastewater, showing obvious economic value in the field of sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of the preparation process of the porous carbon material of the present invention.

[0035] Figure 2 This is a process flow chart for preparing the modified porous carbon-based material described in the present invention.

[0036] Figure 3 This is a SEM image of the intermediate product prepared in Example 1 of the present invention: porous carbon material.

[0037] Figure 4 This is a SEM image of the intermediate product prepared in Comparative Example 2 of the present invention: porous carbon material.

[0038] Figure 5 This is a SEM image of the intermediate product prepared in Comparative Example 3 of the present invention: porous carbon material.

[0039] Figure 6 This is a SEM image of the intermediate product prepared in Comparative Example 4 of the present invention: porous carbon material. DETAILED DESCRIPTION

[0040] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] See also Figure 1-6 , the present invention provides a technical solution:

[0042] Example 1

[0043] A method for preparing a modified porous carbon-based composite material:

[0044] S1. Preparation of porous carbon materials:

[0045] S101. The wood chips were washed with water and dried, crushed, and sieved to obtain wood powder;

[0046] S102. 10 g of the sawdust powder was placed in a porcelain boat in a tube furnace and calcined at 600 ° C under a nitrogen atmosphere for 2 h to obtain a carbonized powder, labeled AC-1.

[0047] S103. Weigh 2 g AC-1, 0.5 g K2CO3, and 1.5 g NH4Cl, respectively, mix and grind for 30 min, and dry the resulting mixture at 80 ° C for 10 h;

[0048] S104. The mixture obtained by step S3 is placed in a porcelain boat in a tube furnace and calcined twice under a nitrogen atmosphere at a temperature of 800°C for 2h.

[0049] S105. The mixture treated in step S4 is removed, cooled to room temperature, washed with 1 mol / L hydrochloric acid for 5 min, then washed with deionized water until neutral, and finally dried at 100°C to obtain a porous carbon material;

[0050] S2. Preparation of modified porous carbon-based composite materials:

[0051] S201. 1g of trimethyl borate and 2g of tetrabutyl titanate were dissolved in 10ml of ethanol and stirred at room temperature for 20min to mix thoroughly;

[0052] S202. Aqueous ammonia at a concentration of 0.5 mol / L was added dropwise to the solution obtained in step S201, the pH of the solution was controlled to 9, and the temperature was controlled to 30°C to induce hydrolysis and polycondensation reactions. The mixture was stirred for 1 hour to form a transparent sol-like substance.

[0053] S203. 2 g of porous carbon material was mixed with 10 g of the sol-like substance obtained in step S202 and immersed in a vacuum condition of 0.05 MPa for 2 h to promote better penetration of the sol into the pores of the porous carbon material;

[0054] S204. After the impregnation is completed, the sol containing the porous carbon material is allowed to stand at room temperature for 12 h, and then dried at 60 ° C for 12 h;

[0055] S205. The sol containing the porous carbon material treated in step S204 is calcined at a temperature of 400°C, a heating rate of 5°C / min, and a calcination time of 2h. After cooling to room temperature, the modified porous carbon-based composite material is obtained.

[0056] Example 2

[0057] A method for preparing a modified porous carbon-based composite material:

[0058] S1. Preparation of porous carbon materials:

[0059] S101. The wood chips were washed with water and dried, crushed, and sieved to obtain wood powder;

[0060] S102. 10 g of the sawdust powder was placed in a porcelain boat in a tube furnace and calcined at 600 ° C under a nitrogen atmosphere for 2 h to obtain a carbonized powder labeled AC-2.

[0061] S103. Weigh 3 g AC-2, 1 g K2CO3, and 2 g NH4Cl, respectively, mix and grind them for 30 min, and dry the resulting mixture at 90 ° C for 10 h;

[0062] S104. The mixture obtained by step S3 is placed in a porcelain boat in a tube furnace and calcined twice under a nitrogen atmosphere at a temperature of 800°C for 3h.

[0063] S105. The mixture treated in step S4 is removed, cooled to room temperature, washed with 2 mol / L hydrochloric acid for 5 min, then washed with deionized water until neutral, and finally dried at 120°C to obtain a porous carbon material;

[0064] S2. Preparation of modified porous carbon-based composite materials:

[0065] S201 2g of trimethyl borate and 4g of tetrabutyl titanate were dissolved in 15ml of ethanol and stirred at room temperature for 30min to mix thoroughly;

[0066] S202. Aqueous ammonia having a concentration of 1 mol / L was added dropwise to the solution obtained in step S201, the pH value of the solution was controlled to 11, and the temperature was controlled to 30°C to induce hydrolysis and polycondensation reactions. The mixture was stirred for 2 h to form a transparent sol-like substance.

[0067] S203. 2 g of porous carbon material was mixed with 15 g of the sol-like substance obtained in step S202 and immersed in a vacuum condition of 0.1 MPa for 3 h to promote better penetration of the sol into the pores of the porous carbon material;

[0068] S204. After the impregnation is completed, the sol containing the porous carbon material is allowed to stand at room temperature for 12 h, and then dried at 60 ° C for 12 h;

[0069] S205. The sol containing the porous carbon material treated in step S204 is calcined at a temperature of 500°C, a heating rate of 5°C / min, and a calcination time of 3 hours. After cooling to room temperature, the modified porous carbon-based composite material is obtained.

[0070] Example 3

[0071] A method for preparing a modified porous carbon-based composite material:

[0072] S1. Preparation of porous carbon materials:

[0073] S101. The pine cones were washed with water and dried, crushed, and sieved to obtain pine cone powder;

[0074] S102. 10 g of the pine cone powder was placed in a porcelain boat in a tube furnace and calcined at 700 ° C under a nitrogen atmosphere for 2 h to obtain a carbonized powder labeled AC-3.

[0075] S103. Weigh 3 g AC-3, 1.5 g K2CO3, and 1.5 g NH4Cl, respectively, mix and grind for 30 min, and dry the resulting mixture at 90 ° C for 10 h;

[0076] S104. The mixture obtained by step S3 is placed in a porcelain boat in a tube furnace and calcined twice under a nitrogen atmosphere at a temperature of 900°C for 2h.

[0077] S105. The mixture treated in step S4 is removed, cooled to room temperature, washed with 1.5 mol / L hydrochloric acid for 5 min, then washed with deionized water until neutral, and finally dried at 120°C to obtain a porous carbon material;

[0078] S2. Preparation of modified porous carbon-based composite materials:

[0079] S201 2g of trimethyl borate and 4g of tetrabutyl titanate were dissolved in 20ml of ethanol and stirred at room temperature for 30min to mix thoroughly;

[0080] S202. Aqueous ammonia having a concentration of 1 mol / L was added dropwise to the solution obtained in step S201, the pH value of the solution was controlled to 10, and the temperature was controlled to 30°C to induce hydrolysis and polycondensation reactions. The mixture was stirred for 1.5 h to form a transparent sol-like substance.

[0081] S203. 2 g of porous carbon material was mixed with 10 g of the sol-like substance obtained in step S202 and immersed in a vacuum condition of 0.1 MPa for 3 h to promote better penetration of the sol into the pores of the porous carbon material;

[0082] S204. After the impregnation is completed, the sol containing the porous carbon material is allowed to stand at room temperature for 12 h, and then dried at 60 ° C for 12 h;

[0083] S205. The sol containing the porous carbon material treated in step S204 is calcined at a temperature of 400°C, a heating rate of 5°C / min, and a calcination time of 3 hours. After cooling to room temperature, the modified porous carbon-based composite material is obtained.

[0084] Comparative Example:

[0085] Comparative Example 1: There are the following differences between Comparative Example 1 and Example 1. The only difference is that in Comparative Example 1, step S2 originally existing in Example 1 is omitted, thereby omitting the preparation of the modified porous carbon-based composite material. In Comparative Example 1, only porous carbon material is prepared, and the remaining steps are exactly the same in Comparative Example 1 and Example 1.

[0086] Comparative Example 2: Comparative Example 2 differs from Example 1 in that the composite activator component in step S103 originally present in Example 1 is omitted in Comparative Example 2. In Comparative Example 2, the composite activator component is not added, and the remaining steps are exactly the same in Comparative Example 2 and Example 1.

[0087] Comparative Example 3: Comparative Example 3 differs from Example 1 in that, in Comparative Example 3, the composite activator components in step S103 originally present in Example 1 are partially omitted, and only NH4Cl is added in Comparative Example 3. The remaining steps are exactly the same in Comparative Example 3 and Example 1.

[0088] Comparative Example 4: Comparative Example 4 differs from Example 1 in that the composite activator component in step S103 originally present in Example 1 is partially omitted in Comparative Example 4, and only K2CO3 is added in Comparative Example 4. The remaining steps are exactly the same in Comparative Example 4 and Example 1.

[0089] Comparative Example 5: Comparative Example 5 differs from Example 1 in the following ways: in Comparative Example 5, step S201 originally existing in Example 1 is partially omitted, trimethyl borate is not added, and the remaining steps are exactly the same in Comparative Example 5 and Example 1.

[0090] Performance testing:

[0091] The specific surface area and pore volume of the porous carbon materials (intermediate products) prepared in Examples 1-3 and Comparative Examples 1-5 were tested. The test results are shown below:

[0092] Table 1. Comparison of specific surface area and pore volume of porous carbon materials prepared in Examples 1-3 and Comparative Examples 1-5

[0093]

[0094] The SEM images of the porous carbon materials obtained in Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 are as follows: Figure 3-6 As shown in Table 1 and Figure 3 It can be seen that the porous carbon material prepared in step S1 of Example 1 has a honeycomb structure. In addition to micropores, there are also a large number of mesopores, which can provide more active sites and a larger reaction space. Figure 4 It can be seen that the intermediate product porous carbon material prepared in Comparative Example 2 is an irregular solid three-dimensional structure. From Table 1, it can be seen that the specific surface area and pore volume of the porous carbon material obtained in Comparative Example 2 are very small; Figure 5 As shown, Comparative Example 3 is an intermediate product porous carbon material prepared by adding only NH4Cl. Compared with Comparative Example 2, flakes and smooth spheres appear. As can be seen from Table 1, the specific surface area and pore volume of the porous carbon material obtained are increased, indicating that NH4Cl has a certain activation and pore-forming effect; Figure 6 As shown, Comparative Example 4 is a porous carbon material prepared by adding only K2CO3. The surface appears to be a rough morphology with small particles attached. As can be seen from Table 1, compared with Example 1, the specific surface area and pore volume of the porous carbon material obtained in Comparative Example 4 are still relatively small, indicating that K2CO3 alone is not enough to activate the carbon and the formed pore structure is not rich enough. Figure 3-6Compared with Table 1, the composite activator provided by the present invention has a synergistic effect on the pore formation of biochar, which can greatly increase the pore volume of the prepared porous carbon material, create favorable conditions for the subsequent introduction of boron-containing precursors and titanium precursors, and finally prepare a composite material containing porous carbon, boron species and TiO2.

[0095] The modified porous carbon-based composite materials prepared in Examples 1-3 and Comparative Examples 1-5 were put into simulated wastewater for adsorption experiments. The specific steps are as follows: 500 ml of Cd 2+ 、Cu 2+ Cr 3+ , Pb 2+ , and the concentration of methylene blue were 100 mg / L simulated contaminated liquid, the modified porous carbon-based composite materials prepared in Examples 1-3 and Comparative Examples 1-5 were respectively put into the above simulated contaminated liquid, and the amount was 1% of the simulated contaminated liquid. The adsorption experiments were carried out under the conditions of 300W xenon lamp irradiation and dark protection, temperature 25 ° C, stirring rate 800 r / min, time 30min, sedimentation filtration, and Cd were calculated respectively. 2 + 、Cu 2+ Cr 3+ , Pb 2+ , the removal rate of methylene blue, the results are as follows:

[0096] Table 2. Summary of adsorption experimental data

[0097]

[0098] As can be seen from Table 2, the porous carbon-based composite materials prepared in Examples 1-3 of the present invention all showed good removal capabilities for heavy metal ions and organic pollutants, can be used to treat common pollutant components in wastewater, and have good application prospects. Under dark and light-proof conditions, the modified porous carbon-based composite materials still have significant removal efficiency for a variety of pollutants, indicating that the prepared modified porous carbon-based composite materials have good adsorption effects; the difference in adsorption performance between Example 1 and Comparative Example 1 proves that the present invention successfully doped boron and titanium dioxide into the pores of the porous carbon material by infiltrating a sol containing a boron precursor and a titanium precursor into the pores of the porous carbon material and calcining the same, thereby achieving modification of the porous carbon material, so that the modified porous carbon material has a more complex pore structure, more surface defects and richer functional groups, thereby enhancing its adsorption of heavy metal ions and organic matter in wastewater. Energy; The difference in removal rate of different pollutants under dark conditions between Example 1 and Comparative Examples 2-4 shows that the present invention can greatly improve the pore volume and the number of mesopores of the porous carbon material and improve its adsorption performance by using a compound activator and applying it to the preparation process of the porous carbon material. Furthermore, the photocatalytic experiment conducted under the irradiation of a 300W xenon lamp shows that a larger pore volume and a larger number of mesopores are conducive to the introduction of more boron-containing precursors and titanium precursors into the pores of the porous carbon material, so that the porous carbon-based composite material obtained after calcination can degrade pollutants through a synergistic photocatalytic reaction, thereby improving the removal efficiency of pollutants in wastewater, which is consistent with the phenomenon described in the aforementioned SEM characterization part; The difference in pollutant removal rate between Example 1 and Comparative Example 5 is presumably due to the fact that the boron element was not introduced, which reduced the number of holes on the surface of titanium dioxide and the oxidation sites, resulting in a decrease in its photocatalytic ability.

[0099] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a modified porous carbon-based composite material, characterized in that: The following steps are involved: S1. Preparation of porous carbon materials: S101. The biomass raw material is washed with water and dried, crushed, and sieved to obtain a biomass powder; S102. The biomass powder is placed in a porcelain boat in a tube furnace and calcined at 600-700 ° C under a nitrogen atmosphere for 2-3 h to obtain a carbonized powder, labeled AC. S103. Weigh 2-3 parts of AC and 2-3 parts of the composite activator in parts by mass, mix and grind the two for 30-40 minutes, and dry the resulting mixture at 80-90 ° C for 10-12 hours; S104. The mixture obtained by step S103 is placed in a porcelain boat in a tube furnace and calcined twice under a nitrogen atmosphere at a temperature of 800-900°C for a treatment time of 2-3h. S105. The mixture treated in step S4 is removed, cooled to room temperature, washed with hydrochloric acid for 5-6 minutes, then washed with deionized water until neutral, and finally dried at 100-120 ° C to obtain a porous carbon material; S2. Preparation of modified porous carbon-based composite materials: S201. 1-2 parts by mass of trimethyl borate and 2-4 parts of tetrabutyl titanate are dissolved in 10-20 parts of ethanol and stirred at room temperature for 20-30min to mix thoroughly; S202. Aqueous ammonia was added dropwise to the solution obtained in step S201 to control the pH of the solution to 9-11, initiating hydrolysis and polycondensation reactions, and stirring was continued for 1-2 hours to form a transparent sol-like substance; S203. The porous carbon material and the sol-like substance obtained in step S202 are mixed uniformly in a mass ratio of 1:5-1:10 and immersed in a vacuum condition for 2-4 hours to promote better penetration of the sol into the pores of the porous carbon material; S204. After the impregnation is completed, the sol containing the porous carbon material is allowed to stand at room temperature for 12-18 hours, and then dried at 60-80°C for 12-15 hours; S205. The sol containing the porous carbon material treated in step S204 is calcined to obtain the modified porous carbon-based composite material; In step S103, the composite activator is a mixture of K2CO3 and NH4Cl in a mass ratio of 0.001-1:1-3.

2. The method for preparing a modified porous carbon-based composite material according to claim 1, wherein: In step S101, the biomass raw material is one or more of wood chips, pine cones, rice straw, and sugarcane bagasse.

3. The method for preparing a modified porous carbon-based composite material according to claim 1, wherein: In step S105, the concentration of hydrochloric acid is 1-2 mol / L.

4. The method for preparing a modified porous carbon-based composite material according to claim 1, wherein: In step S202, the concentration of the ammonia water is 0.5-1 mol / L.

5. The method for preparing a modified porous carbon-based composite material according to claim 1, wherein: During the reaction of step S202, the temperature is maintained at 30-40°C.

6. The method for preparing a modified porous carbon-based composite material according to claim 1, wherein: In step S203, the vacuum condition is a vacuum degree of 0.05-0.1 MPa.

7. The method for preparing a modified porous carbon-based composite material according to claim 1, wherein: In step S205, the calcination process is performed under the following operating parameters: calcination temperature of 400-600°C, calcination time of 2-4 hours, heating rate of 5°C / min, and protective gas N2 flow rate of 50-80 sccm.

8. A modified porous carbon-based composite material, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 7.

9. Use of the modified porous carbon-based composite material obtained by the preparation method according to any one of claims 1 to 7 or the modified porous carbon-based composite material according to claim 8 in wastewater treatment.

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