Activated carbon composite material and preparation method thereof

Abstract

The invention relates to the technical field of activated carbon materials, in particular to an activated carbon composite material and a preparation method thereof. The activated carbon composite material comprises the following raw materials: raw coal, melamine, thiourea, potassium chloride and urea, and the preparation method comprises the following steps: taking the components in the raw materials according to a certain molar ratio, mixing, grinding and drying to obtain a mixed material; heating the mixed material under the protection of nitrogen, and carrying out heat preservation to carry out pyrolytic reaction; and soaking and washing the pyrolysis product with an acidic solution, washing with water until the product is neutral, and drying to obtain the product. The composite material prepared by the invention has high specific surface area, realizes efficient in-situ doping of nitrogen and sulfur double heteroatoms, and has excellent electrochemical performance, cycling stability and outstanding pollutant adsorption capacity. The preparation method of the activated carbon composite material is simple, and has the advantages of low raw material cost, mild reaction conditions, environmental friendliness and the like. The invention provides a new thought for high-value utilization of the coal-based material.

Description

Technical Field

[0001] This invention relates to the field of activated carbon materials technology, specifically to an activated carbon composite material and its preparation method. Background Technology

[0002] Activated carbon, a porous carbon material with a highly developed pore structure and high specific surface area, has adsorption performance mainly determined by its pore size distribution, surface chemical properties, and microstructure. Traditional activated carbon preparation methods mainly include physical activation and chemical activation. Physical activation typically uses steam or carbon dioxide as an activating agent, oxidizing and etching the carbon precursor at 800-1000℃. The specific surface area of ​​the prepared activated carbon is generally 1000-1500 m². 2 Within the range of / g; chemical activation methods, using chemical reagents such as KOH and ZnCl2 as activators, can achieve higher specific surface areas, but suffer from problems such as severe equipment corrosion and difficulty in wastewater treatment. In recent years, with increasingly stringent environmental protection requirements and the expansion of emerging application fields, the development of green and efficient activated carbon preparation technologies has become a research hotspot.

[0003] Coal-based activated carbon plays a vital role in industrial water treatment and gas purification due to its wide availability of raw materials and low cost. However, conventional coal-based activated carbon faces several technical bottlenecks: First, the ash content of raw coal is generally high (8%-20%), resulting in a large residual ash content in the activated carbon product, reducing the number of effective adsorption sites. Second, the complex organic composition of coal leads to a wide pore size distribution and a low mesopore ratio (typically <30%) in activated carbon obtained through direct pyrolysis activation, limiting its adsorption efficiency for macromolecular pollutants. Third, the surface chemistry of coal-based activated carbon is relatively inert, with a limited number of functional groups, resulting in poor selectivity for adsorption of polar substances. These shortcomings severely restrict the application of coal-based activated carbon in high-value-added fields.

[0004] Heteroatom doping is an effective means of improving the performance of carbon materials. The introduction of heteroatoms such as nitrogen and sulfur can significantly change the electronic structure of carbon materials, increase surface active sites, and improve the adsorption capacity for specific substances. Currently, the preparation methods of heteroatom-doped activated carbon mainly include post-treatment and in-situ doping methods: the post-treatment method involves reacting pre-prepared activated carbon with nitrogen / sulfur-containing compounds (such as ammonia and hydrogen sulfide) at high temperatures. This method has poor doping uniformity and is complex; the in-situ doping method involves directly introducing nitrogen / sulfur-containing substances into the carbon precursor for co-pyrolysis. Although the process is simple, heteroatoms are easily lost during high-temperature pyrolysis, resulting in low doping efficiency. How to achieve efficient and stable heteroatom doping is one of the key challenges in the current research on the improvement of coal-based activated carbon. Therefore, developing a coal-based activated carbon preparation method that is simple in process, low in cost, and can simultaneously achieve precise control of pore structure and efficient heteroatom doping is of great significance for enhancing the competitiveness of my country's activated carbon industry and promoting the high-value utilization of coal resources.

[0005] Based on this, the present invention has successfully prepared a coal-based activated carbon composite material with high specific surface area, hierarchical pore structure and abundant heteroatom doping by optimizing the raw material ratio and pyrolysis process. Summary of the Invention

[0006] The purpose of this invention is to provide an activated carbon composite material and its preparation method.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The raw material composition of the activated carbon composite material of the present invention is: raw coal, melamine, thiourea, potassium chloride and urea in a molar ratio of 1:5-15:0.5-2:0.3-1.5:0.2-1.

[0008] Preferably, the raw material composition of the activated carbon composite material of the present invention is: raw coal, melamine, thiourea, potassium chloride and urea in a molar ratio of 1:8-12:1-1.5:0.5-1:0.5-1.

[0009] More preferably, the raw material composition of the activated carbon composite material of the present invention is: raw coal, melamine, thiourea, potassium chloride and urea in a molar ratio of 1:10:1.2:1:0.8.

[0010] Preferably, in the raw material composition of the activated carbon composite material of the present invention, the raw coal is high volatile bituminous coal crushed to 100 mesh, with a volatile content ≥35% and an ash content ≤8%.

[0011] The preparation method of the activated carbon composite material of the present invention includes the following steps: Step 1: Take raw coal, melamine, thiourea, potassium chloride and urea according to the raw material composition, mix and grind them, and dry them at 70-100℃ to obtain a mixture. Step 2: Under nitrogen protection, heat the mixture to 750-900℃ at a heating rate of 5-8℃ / min and hold for 1-4 hours to carry out the pyrolysis reaction; Step 3: The obtained pyrolysis product is first soaked and washed with an acidic solution of 0.5-1.5 mol / L 1-4 times, each time for 0.5-2 hours, then washed with deionized water until neutral, and dried at 80-120℃ for 1-24 hours to obtain the activated carbon composite material; wherein, the acidic solution is any one or more of nitric acid, hydrochloric acid, and sulfuric acid.

[0012] Preferably, in the preparation method of the activated carbon composite material of the present invention, the mixing and grinding method in step one is ball milling, specifically: ball milling at 300 rpm for 2 hours.

[0013] Preferably, in the preparation method of the activated carbon composite material of the present invention, step two specifically involves: heating the mixture to 780-830°C at a heating rate of 5-8°C / min under nitrogen protection, and holding at this temperature for 2-3 hours to carry out a pyrolysis reaction.

[0014] In a further preferred embodiment, in the preparation method of the activated carbon composite material of the present invention, step two specifically involves: heating the mixture to 800°C at a heating rate of 5-8°C / min under nitrogen protection, and holding at this temperature for 2.5 hours to carry out a pyrolysis reaction.

[0015] Preferably, in the preparation method of the activated carbon composite material of the present invention, step three specifically involves: soaking and washing the obtained pyrolysis product in 0.5-1 mol / L hydrochloric acid solution 2-4 times, each time for 1-1.5 h, then washing it with deionized water until neutral, and drying it at 80-100℃ for 8-16 h to obtain the activated carbon composite material.

[0016] In a further preferred embodiment, in the preparation method of the activated carbon composite material of the present invention, step three specifically involves: soaking and washing the obtained pyrolysis product three times with a 1 mol / L hydrochloric acid solution for 1 hour each time, then washing it with deionized water until neutral, and drying it at 80°C for 12 hours to obtain the activated carbon composite material.

[0017] The beneficial effects of this invention are: 1. This invention is the first to propose using raw coal, melamine, thiourea, and potassium chloride urea as raw materials for the pyrolysis reaction of porous doped activated carbon, making full use of the relatively high specific surface area of ​​the carbon precursor.

[0018] 2. This invention innovatively adopts a thiourea-urea-potassium chloride ternary synergistic system to develop a method for preparing a high-efficiency coal-based activated carbon composite material. The efficient in-situ doping of nitrogen and sulfur dual heteroatoms is achieved through the staged pyrolysis of thiourea. The total nitrogen content in the obtained activated carbon composite material can reach up to 24.9 wt%, the sulfur content can reach up to 6.5 wt%, and the doping uniformity is good.

[0019] 3. This invention utilizes the molten salt properties of potassium chloride to achieve efficient activation of coal-based carbon materials at relatively low temperatures. Simultaneously, it leverages the gas template effect of urea to form an ultra-microporous network, resulting in an activated carbon composite material with a hierarchical pore structure and a specific surface area as high as 1226.8 m². 2 / g.

[0020] 4. The activated carbon composite material provided by this invention exhibits excellent electrochemical performance and cycle stability, and has outstanding pollutant adsorption capacity, with a benzene adsorption capacity as high as 412 mg / g.

[0021] 5. The preparation method of the activated carbon composite material provided by the present invention is simple and has the advantages of low raw material cost, mild reaction conditions and environmental friendliness. It is suitable for industrial production and provides a new idea for the high-value utilization of coal-based materials. Attached Figure Description

[0022] Figure 1 XRD curves of high specific surface area heteroatom-doped activated carbon materials prepared by pyrolysis at 800℃; Figure 2 Isothermal adsorption-desorption curves of high specific surface area heteroatom-doped activated carbon materials prepared by pyrolysis at 800℃; Figure 3 BJH desorption pore size diagram of high specific surface area heteroatom-doped activated carbon material prepared by pyrolysis at 800℃; Figure 4 Raman spectra of high specific surface area heteroatom-doped activated carbon materials prepared at different pyrolysis temperatures; Figure 5 FT-IR images of high specific surface area heteroatom-doped activated carbon materials prepared at different pyrolysis temperatures. Detailed Implementation

[0023] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The following embodiments are for explanation and illustration only, and do not constitute a limitation on the technical solution of the present invention.

[0024] Example 1 The activated carbon composite material is composed of raw coal (Xinjiang high volatile bituminous coal, volatile content ≥35%, ash content ≤8%) crushed to 100 mesh in a molar ratio of 1:10:1.2:1:0.8, melamine, thiourea, potassium chloride and urea.

[0025] The preparation method of the above activated carbon composite material is as follows: Step 1: Take raw coal, melamine, thiourea, potassium chloride and urea according to the raw material composition, ball mill them at 300 rpm for 2 hours, and dry them at 80℃ to obtain the mixture. Step 2: The mixture is heated to 800℃ under nitrogen protection (nitrogen flow rate of 50 mL / min) at a heating rate of 5℃ / min, and held at this temperature for 2.5 h to carry out the pyrolysis reaction; Step 3: The obtained pyrolysis product is first soaked and washed three times with 1 mol / L hydrochloric acid solution for 1 h each time, then washed with deionized water until neutral, and dried at 80℃ for 12 h to obtain activated carbon composite material.

[0026] Example 2 The activated carbon composite material is composed of raw coal (Xinjiang high volatile bituminous coal, volatile content ≥35%, ash content ≤8%) crushed to 100 mesh in a molar ratio of 1:5:0.5:0.3:0.2, melamine, thiourea, potassium chloride and urea.

[0027] The preparation method of the above activated carbon composite material is as follows: Step 1: Take raw coal, melamine, thiourea, potassium chloride and urea according to the raw material composition, ball mill them at 300 rpm for 2 hours, and dry them at 70℃ to obtain the mixture. Step 2: The mixture is heated to 750°C under nitrogen protection (nitrogen flow rate of 50 mL / min) at a heating rate of 5°C / min, and held at this temperature for 4 h to carry out the pyrolysis reaction; Step 3: The obtained pyrolysis product is first soaked and washed three times with 1 mol / L nitric acid solution for 1 h each time, then washed with deionized water until neutral, and dried at 120℃ for 8 h to obtain activated carbon composite material.

[0028] Example 3 The activated carbon composite material is composed of raw coal (Xinjiang high volatile bituminous coal, volatile content ≥35%, ash content ≤8%) crushed to 100 mesh in a molar ratio of 1:15:2:1.5:1, melamine, thiourea, potassium chloride and urea.

[0029] The preparation method of the above activated carbon composite material is as follows: Step 1: Take raw coal, melamine, thiourea, potassium chloride and urea according to the raw material composition, ball mill them at 300 rpm for 2 hours, and dry them at 100℃ to obtain the mixture. Step 2: The mixture is heated to 870°C under nitrogen protection (nitrogen flow rate of 50 mL / min) at a heating rate of 8°C / min, and held at this temperature for 1 h to carry out the pyrolysis reaction; Step 3: The obtained pyrolysis product is first soaked and washed three times with 1 mol / L sulfuric acid solution for 1 h each time, then washed with deionized water until neutral, and dried at 90℃ for 16 h to obtain activated carbon composite material.

[0030] Example 4 The activated carbon composite material is composed of raw coal (Xinjiang high volatile bituminous coal, volatile content ≥35%, ash content ≤8%) crushed to 100 mesh in a molar ratio of 1:10:1.2:1:0.8, melamine, thiourea, potassium chloride and urea.

[0031] The preparation method of the above activated carbon composite material is as follows: Step 1: Take raw coal, melamine, thiourea, potassium chloride and urea according to the raw material composition, ball mill them at 300 rpm for 2 hours, and dry them at 80℃ to obtain the mixture. Step 2: The mixture is heated to 800℃ under nitrogen protection (nitrogen flow rate of 50 mL / min) at a heating rate of 5℃ / min, and held at this temperature for 2.5 h to carry out the pyrolysis reaction; Step 3: The obtained pyrolysis product is first soaked and washed 4 times with 0.5 mol / L hydrochloric acid solution for 0.5 h each time, then washed with deionized water until neutral, and dried at 80℃ for 12 h to obtain activated carbon composite material.

[0032] Example 5 The activated carbon composite material is composed of raw coal (Xinjiang high volatile bituminous coal, volatile content ≥35%, ash content ≤8%) crushed to 100 mesh in a molar ratio of 1:10:1.2:1:0.8, melamine, thiourea, potassium chloride and urea.

[0033] The preparation method of the above activated carbon composite material is as follows: Step 1: Take raw coal, melamine, thiourea, potassium chloride and urea according to the raw material composition, ball mill them at 300 rpm for 2 hours, and dry them at 80℃ to obtain the mixture. Step 2: The mixture is heated to 800℃ under nitrogen protection (nitrogen flow rate of 50 mL / min) at a heating rate of 5℃ / min, and held at this temperature for 2.5 h to carry out the pyrolysis reaction; Step 3: The obtained pyrolysis product is first soaked and washed with 1.5 mol / L hydrochloric acid solution for 2 h, then washed with deionized water until neutral, and dried at 80℃ for 12 h to obtain activated carbon composite material.

[0034] Example 6 The activated carbon composite material is composed of raw coal (Xinjiang high volatile bituminous coal, volatile content ≥35%, ash content ≤8%) crushed to 100 mesh in a molar ratio of 1:10:1.2:1:0.8, melamine, thiourea, potassium chloride and urea.

[0035] The preparation method of the above activated carbon composite material is as follows: Step 1: Take raw coal, melamine, thiourea, potassium chloride and urea according to the raw material composition, ball mill them at 300 rpm for 2 hours, and dry them at 80℃ to obtain the mixture. Step 2: The mixture is heated to 800℃ under nitrogen protection (nitrogen flow rate of 50 mL / min) at a heating rate of 5℃ / min, and held at this temperature for 2.5 h to carry out the pyrolysis reaction; Step 3: The obtained pyrolysis product is first soaked and washed twice with 1 mol / L hydrochloric acid solution for 1.5 h each time, then washed with deionized water until neutral, and dried at 80℃ for 12 h to obtain activated carbon composite material.

[0036] To further verify the reliability of the present invention and select the optimal solution, the inventors conducted a series of experiments, as follows: 1. Main instruments and reagents Main instruments: vacuum tube furnace (model: OTF-1200X), planetary ball mill (model: XQM-2L), precision pH meter.

[0037] Main reagents: Xinjiang raw coal, melamine, thiourea, potassium chloride, urea, hydrochloric acid.

[0038] 2. Experimental Methods To accurately evaluate the material properties, the following characterization methods were used in this experiment: (1) X-ray diffraction (XRD) Test method: The dry sample powder is evenly spread in the sample cell, the scanning range (2θ) is 10° to 80°, and the scanning speed is 5° / min.

[0039] (2) BET specific surface area and pore size analysis Test method: Before the test, the sample was degassed under vacuum at 300℃ for 6 h to completely remove surface adsorbates, and then nitrogen adsorption-desorption test was performed at -196℃ (liquid nitrogen temperature).

[0040] (3) Raman spectroscopy Test method: Place the sample under a microscope at 1000 cm. -1 Up to 2000 cm -1 The laser is scanned within the beam range, and the laser power is controlled within 50 mW to avoid sample damage.

[0041] (4) Fourier transform infrared spectroscopy (FT-IR) Test method: The KBr pellet method was used. A small amount of sample was mixed with dry KBr powder, ground, and pressed into a transparent thin film. The scanning range was 4000-400 cm⁻¹. -1 The resolution is 4 cm. -1 .

[0042] 3. Preparation of high specific surface area heteroatom-doped activated carbon materials 3.1 Preparation method High-volatile bituminous coal (volatile content ≥35%, ash content ≤8%) from Hami, Xinjiang, melamine, thiourea, potassium chloride, and urea were mixed and ground in a molar ratio of 1:5-15:0.5-2:0.3-1.5:0.2-1 and dried. The mixture was then heated to 750-900℃ at a heating rate of 5-8℃ under a protective atmosphere (nitrogen protection, flow rate 50 mL / min) and held for 1-4 h for pyrolysis. The pyrolysis product was first washed and soaked three times with an acidic solution (nitric acid, hydrochloric acid, or sulfuric acid) for 1 h each time, then washed with water until neutral, and dried at 80-120℃ for 1-24 h to obtain a heteroatom-doped activated carbon composite material with high specific surface area.

[0043] 3.2 Experimental Example Activated carbon composite materials were prepared under different parameter conditions using the methods described in section 3.1, and the prepared activated carbon composite materials were characterized using the methods described in section 2. Experimental methods.

[0044] (1) Experimental Example 1 High-volatile bituminous coal (≥35% volatile matter content, ≤8% ash content) from Hami, Xinjiang was pulverized to 100 mesh and weighed with melamine, thiourea, potassium chloride, and urea in a molar ratio of 1:10:1.2:1:0.8. The raw materials were placed in a ball mill and mixed at 300 rpm for 2 h. The uniformly mixed material was placed in a tube furnace and heated to 800℃ at a heating rate of 5℃ / min under nitrogen protection (flow rate of 50 mL / min) and held for 2.5 h. After the reaction system cooled naturally to room temperature, the product was removed, washed three times with 1 mol / L hydrochloric acid solution for 1 h each time, and then washed with deionized water until neutral. The product was placed in a vacuum drying oven and dried at 80℃ for 12 h to obtain the activated carbon composite material.

[0045] The activated carbon composite material prepared in this experimental example was characterized, and the results are as follows: 1) XRD test The XRD curve of the high specific surface area heteroatom-doped activated carbon material prepared by pyrolysis at 800℃ is shown below. Figure 1 As shown. By Figure 1 The XRD curves show broadened diffraction peaks at 2θ≈24° and 44°, corresponding to the (002) and (100) crystal planes of graphite, respectively. The broadened peaks indicate that the material is primarily an amorphous carbon structure with a low degree of graphitization, which is related to the pyrolysis temperature (800℃), insufficient to form highly ordered graphite crystals. Furthermore, no obvious impurity peaks were observed, indicating that template agents such as potassium chloride were effectively removed during the washing process.

[0046] The results show that pyrolysis temperature and time affect the crystallinity of carbon; lower temperatures (700℃) may lead to a broader peak, while higher temperatures (900℃) may enhance graphitization. Figure 1 It shows moderate graphitization and meets the pyrolysis conditions of 800℃.

[0047] 2) Specific surface area test (BET method) The isothermal adsorption-desorption curves of high specific surface area heteroatom-doped activated carbon materials prepared by pyrolysis at 800℃ are shown below. Figure 2 As shown, the BJH aperture distribution diagram is as follows: Figure 3 As shown.

[0048] Depend on Figure 2 The isothermal adsorption-desorption curves exhibit Type IV characteristics, accompanied by an H4-type hysteresis loop, indicating the presence of a mesoporous structure in the material. Within the relative pressure (P / P0) range of 0.4–0.9, the adsorption capacity increases significantly, indicating that mesopores dominate. Calculations using the BET model show that the specific surface area of ​​the material is 1226.8 m². 2 / g, total pore volume is 1.6 m 3 / g.

[0049] BJH aperture distribution diagram ( Figure 3 The results show that the pore size is mainly concentrated in the range of 2-5 nm, with a peak at about 4 nm, indicating that the material is mainly mesoporous. This distribution is conducive to adsorption because mesopores provide effective mass transfer channels.

[0050] The results showed that, firstly, potassium chloride and urea, acting as template agents and activators, were added to the raw materials, promoting the formation of mesopores. During pyrolysis, the decomposition and volatilization of these components left behind a porous structure. Figure 2 The curve shape verifies the effectiveness of the method; secondly, the introduction of thiourea and urea may have adjusted the pore structure through sulfur and nitrogen doping, while the template effect of potassium chloride ensures the uniformity of pore size. Figure 3 The distribution of the material matches the pyrolysis conditions (800℃, 2.5 h), thus avoiding excessive ablation that could lead to the collapse of the pore structure.

[0051] 3) Raman spectroscopy Raman spectra of high specific surface area heteroatom-doped activated carbon materials prepared at different pyrolysis temperatures are shown below. Figure 4 As shown. The results show that the Raman spectrum at 1350 cm⁻¹... -1 and 1580 cm -1 Distinct D-bands and G-bands appear at the location; the D-band represents defects and disordered structures in carbon materials, while the G-band represents graphitized carbon. Calculate I D / I G A ratio of 1.28 indicates that the material has a high defect density, which is beneficial to adsorption activity and surface reaction.

[0052] The results show that the doping of melamine and thiourea introduces heteroatoms (nitrogen and sulfur), which increases the defects in the carbon skeleton. Figure 4 I D / I G The value reflects the doping effect and is related to the pyrolysis temperature. Higher temperatures may reduce defects, but at 800°C, appropriate defects are maintained.

[0053] 4) FT-IR spectroscopy FT-IR spectra of high specific surface area heteroatom-doped activated carbon materials prepared at different pyrolysis temperatures are shown below. Figure 5 As shown. The results show that the infrared spectrum is at 3450 cm⁻¹. -1 A broad peak is observed at 1550 cm⁻¹, corresponding to the OH stretching vibration; at 1550 cm⁻¹... -1 and 1180 cm -1 The points correspond to C=N and CN vibrations, respectively; at 1050 cm -1The peaks may be due to CS vibration. These peaks indicate the presence of abundant oxygen-, nitrogen-, and sulfur-containing functional groups on the material surface. Measurements showed that the obtained activated carbon composite material contained 24.9 wt% N and 6.5 wt% S.

[0054] The results showed that melamine and thiourea provided nitrogen and sulfur sources, while the oxygen element in the raw coal remained after pyrolysis, forming functional groups. Figure 5 The peak values ​​confirm successful elemental doping, which enhances the surface chemical activity of the material.

[0055] Through the above preparation and characterization, a nitrogen-sulfur co-doped porous activated carbon composite material was successfully synthesized. The raw material combination and pyrolysis conditions in the preparation method optimized the porous structure, surface functional groups, and defect density of the material. Characterization results demonstrated that the material possesses a high specific surface area, a mesopore-dominated pore size distribution, a moderate degree of graphitization, and abundant surface chemical groups. These characteristics make it potentially valuable for applications in adsorption, catalysis, or energy storage.

[0056] (2) Experimental Example 2 The difference between this experimental example and Example 1 is that the pyrolysis temperature was 780℃ and the holding time was 2.5 h. The remaining preparation methods and conditions were the same as in Example 1. After preparation, the obtained activated carbon composite material was characterized, and the results showed a specific surface area of ​​1196.8 m². 2 / g; N content is 23.2 wt%, S content is 6.2 wt%.

[0057] (3) Experimental Example 3 The difference between this experimental example and Experiment 1 is that the pyrolysis temperature was 830℃ and the holding time was 2 h. The remaining preparation methods and conditions were the same as in Experiment 1. After preparation, the obtained activated carbon composite material was characterized, and the results showed a specific surface area of ​​1105.6 m². 2 / g; N content is 22.8 wt%, S content is 4.1 wt%.

[0058] (4) Experimental Example 4 The difference between this experimental example and Example 1 is that the pyrolysis temperature was 870℃ and the holding time was 2 h. The remaining preparation methods and conditions were the same as in Example 1. After preparation, the obtained activated carbon composite material was characterized, and the results showed a specific surface area of ​​1204.6 m². 2 / g; N content is 23.1 wt%, S content is 3.2 wt%.

[0059] 4. Summary and Analysis This study innovatively developed a method for preparing high-performance coal-based activated carbon composite materials using a thiourea-urea-potassium chloride ternary synergistic system. This technology achieves in-situ doping of sulfur and nitrogen (up to 24.9 wt% nitrogen and 6.5 wt% sulfur) through the staged pyrolysis of thiourea, and utilizes the potassium chloride molten salt effect to construct a hierarchical porous structure (with a maximum specific surface area of ​​1226.8 m²). 2 The process involves using urea as a template to form an ultraporous network. The prepared material exhibits excellent electrochemical performance and cycling stability, while also possessing outstanding pollutant adsorption capacity (test results show that its adsorption capacity for benzene is 412 mg / g). This process features low raw material cost, mild reaction conditions (800℃), and environmental friendliness, providing a new approach for the high-value utilization of coal-based materials.

[0060] Tests show that the activated carbon composite material prepared in this invention exhibits a unique wrinkled structure. This special morphology originates from the formation of a graphitic carbon nitride (g-C3N4) intermediate during the pyrolysis of melamine, followed by the release of gas during decomposition at temperatures above 550°C, leaving abundant wrinkles in the carbon matrix. This wrinkled structure significantly improves the material's performance through the following mechanisms: (1) increasing the specific surface area and exposure of active sites, promoting electrolyte wetting; (2) forming a three-dimensional conductive network, improving electron transport; and (3) providing mechanical buffering, enhancing structural stability. Furthermore, tests show that this wrinkled structure, combined with the high specific surface area and nitrogen-sulfur doping, synergistically contributes to its excellent pollutant adsorption performance and potential electrochemical applications.

[0061] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. An activated carbon composite material, characterized in that, The raw material composition of the activated carbon composite material is: raw coal, melamine, thiourea, potassium chloride and urea in a molar ratio of 1:5-15:0.5-2:0.3-1.5:0.2-1.

2. The activated carbon composite material according to claim 1, characterized in that, The raw material composition of the activated carbon composite material is: raw coal, melamine, thiourea, potassium chloride and urea in a molar ratio of 1:8-12:1-1.5:0.5-1:0.5-1.

3. The activated carbon composite material according to claim 2, characterized in that, The raw material composition of the activated carbon composite material is: raw coal, melamine, thiourea, potassium chloride and urea in a molar ratio of 1:10:1.2:1:0.

8.

4. The activated carbon composite material according to any one of claims 1-3, characterized in that, The raw coal is high-volatile bituminous coal crushed to 100 mesh, with a volatile content ≥35% and an ash content ≤8%.

5. The method for preparing the activated carbon composite material according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Take raw coal, melamine, thiourea, potassium chloride and urea according to the raw material composition, mix and grind them, and dry them at 70-100℃ to obtain a mixture. Step 2: Under nitrogen protection, heat the mixture to 750-900℃ at a heating rate of 5-8℃ / min and hold for 1-4 hours to carry out the pyrolysis reaction; Step 3: The obtained pyrolysis product is first soaked and washed with an acidic solution of 0.5-1.5 mol / L 1-4 times, each time for 0.5-2 hours, then washed with deionized water until neutral, and dried at 80-120℃ for 1-24 hours to obtain the activated carbon composite material; wherein, the acidic solution is any one or more of nitric acid, hydrochloric acid, and sulfuric acid.

6. The method for preparing the activated carbon composite material according to claim 5, characterized in that, The mixing and grinding method described in step one is ball milling, specifically: ball milling at 300 rpm for 2 hours.

7. The method for preparing the activated carbon composite material according to claim 5, characterized in that, Step two specifically involves heating the mixture to 780-830°C under nitrogen protection at a heating rate of 5-8°C / min, and holding at that temperature for 2-3 hours to carry out a pyrolysis reaction.

8. The method for preparing the activated carbon composite material according to claim 7, characterized in that, Step two specifically involves heating the mixture to 800°C under nitrogen protection at a heating rate of 5-8°C / min, and holding at that temperature for 2.5 h to carry out a pyrolysis reaction.

9. The method for preparing the activated carbon composite material according to claim 5, characterized in that, The third step is as follows: the obtained pyrolysis product is first soaked and washed with 0.5-1 mol / L hydrochloric acid solution 2-4 times, each time for 1-1.5 h, then washed with deionized water until neutral, and dried at 80-100℃ for 8-16 h to obtain activated carbon composite material.

10. The method for preparing the activated carbon composite material according to claim 9, characterized in that, The third step is as follows: the obtained pyrolysis product is first soaked and washed three times with 1 mol / L hydrochloric acid solution for 1 h each time, then washed with deionized water until neutral, and dried at 80℃ for 12 h to obtain activated carbon composite material.

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