Special carbon black with high specific surface area and preparation method thereof

Abstract

The invention relates to the technical field of carbon black materials, and discloses special carbon black with high specific surface area and a preparation method thereof, and the special carbon black is prepared by pyrolysis and activation treatment of a precursor mixture, a catalyst and a template agent. The precursor mixture contains a biomass refined product, waste polymer pyrolysis oil and a copolymer template agent, and the performance is optimized through a rotating flow field high-temperature reactor and a microwave-assisted activation process. The carbon black has a hierarchical porous structure, the specific surface area reaches 2000-2500m < 2 > / g, the conductivity is improved by 1-2 orders of magnitude, and the chemical properties can be regulated and controlled through surface functionalization. The low-cost and sustainable production is realized, the mechanical strength, the conductivity and the adsorption performance are remarkably improved, and the requirements of the high-end field are met.

Description

Technical Field

[0001] This invention relates to the field of carbon black materials technology, specifically to a special carbon black with high specific surface area and its preparation method. Background Technology

[0002] Carbon black is a functional material widely used in rubber, plastics, coatings, and batteries, and its specific surface area is one of the key factors determining its performance. The specific surface area of ​​conventional furnace-processed carbon black is typically around 1500 m². 2 The specific surface area is around 1 / g, and certain special preparation methods (such as the template method) can further increase the specific surface area, but these often come with increased cost or process complexity. Furthermore, existing high specific surface area carbon blacks still suffer from limitations in practical applications, such as insufficient conductivity, low mechanical strength, surface chemical inertness, and limited functionality, restricting their widespread use in high-end fields. Moreover, existing preparation methods still have room for improvement in precursor selection, reactor design, and process parameter control, especially in terms of low cost, sustainability, and large-scale production, which do not yet fully meet the requirements. Therefore, developing a special carbon black that combines high specific surface area with multiple superior properties has become a key research direction. Summary of the Invention

[0003] In view of this, the purpose of this invention is to propose a special carbon black with high specific surface area and its preparation method. Through innovative structural design and process optimization, the specific surface area, conductivity, mechanical strength and surface chemical activity of carbon black are significantly improved, thereby meeting the demand for high-performance carbon black in high-end fields.

[0004] To achieve the above objectives, the present invention provides a special carbon black with high specific surface area, which is obtained by pyrolysis and activation treatment of 80-120 parts by weight of precursor mixture, 5-10 parts by catalyst and 15-25 parts by template agent.

[0005] Furthermore, the precursor mixture comprises, by weight, 40-60 parts of biomass refining product, 30-50 parts of waste polymer pyrolysis oil, and 10-20 parts of copolymer template agent. The biomass refining product is cellulose nanocrystals or lignin-derived aromatic compounds that have undergone delignification treatment; the waste polymer pyrolysis oil is tire pyrolysis oil after selective enrichment of aromatic hydrocarbon components; and the copolymer template agent is a self-assembled copolymer with a block structure.

[0006] Furthermore, the preparation method of the high specific surface area special carbon black is as follows:

[0007] Under inert gas protection, the biomass refining products are mixed with waste polymer pyrolysis oil, added to an organic solvent, heated to 60-80℃ and stirred to dissolve, to obtain a uniform precursor solution.

[0008] The precursor solution is mixed with the copolymer template agent, a catalyst is added, and the temperature is raised to 80-100℃ to carry out a prepolymerization reaction to form a gel-like intermediate.

[0009] The gel-like intermediate was placed in a high-temperature reactor and heated to 700-900℃ at a heating rate of 10-20℃ / min under a nitrogen atmosphere. The temperature was maintained for 2-4 hours to carry out the pyrolysis reaction. After cooling, the primary carbon material was obtained.

[0010] Primary carbon material is mixed with an activator and placed in a microwave-assisted reactor for activation treatment at a frequency of 2.45 GHz and a power of 500-800 W for 30-60 minutes. After cooling, a special carbon black with a high specific surface area is obtained.

[0011] Preferably, the weight ratio of biomass refining products, waste polymer pyrolysis oil, and copolymer template agent in the step is 4-6:3-5:1-2.

[0012] Preferably, the organic solvent in the step is dimethyl sulfoxide or N,N-dimethylformamide, and the amount added is 5-10 times the weight of the precursor mixture.

[0013] Preferably, the catalyst in the step is iron oxide nanoparticles or nickel oxide nanoparticles with a particle size range of 10-50 nm, and the amount added is 5-10% of the weight of the precursor mixture.

[0014] Preferably, the high-temperature reactor in the above steps adopts a rotating flow field design, with a spiral guide plate inside, and the inner wall of the reactor is coated with a silicon carbide coating to enhance heat transfer efficiency.

[0015] Preferably, the activator in the step is water vapor, carbon dioxide or potassium hydroxide vapor, with a flow rate of 100-300 mL / min and an activation temperature of 800-1000℃.

[0016] Furthermore, the present invention also provides a method for surface functionalization of high specific surface area special carbon black, comprising the following steps: under inert gas protection, dispersing high specific surface area special carbon black in an organic solvent, adding dopant, heating to 120-150℃ and stirring for 4-6 hours, cooling, separating, washing and drying to obtain surface functionalized special carbon black.

[0017] Preferably, the organic solvent is ethanol or isopropanol, and its addition amount is 20-30 times the weight of the high specific surface area special carbon black.

[0018] Preferably, the dopant is a nitrogen-containing compound, an oxygen-containing compound, or a sulfur-containing compound, specifically urea, ammonium nitrate, or ammonium sulfate, and the amount of dopant added is 5-15% of the weight of the high specific surface area special carbon black.

[0019] Technical effects of the present invention:

[0020] The high specific surface area specialty carbon black provided by this invention achieves a significant increase in specific surface area through a multi-level pore structure design, with actual measured values ​​reaching 2000-2500 μm. 2 / g. The hierarchical pore structure consists of micropores, mesopores, and macropores, with micropores accounting for 40-50%, mesopores for 30-40%, and macropores for 10-20%. This structural design not only maximizes the exposed surface area but also improves mass transfer characteristics, enabling it to exhibit excellent performance in adsorption and catalysis applications.

[0021] This invention introduces ultrathin graphene sheets or nanosheets to create numerous edge and defect sites on the carbon black surface. The presence of these sites significantly enhances the conductivity and chemical activity of the carbon black. Experiments show that the conductivity of this special carbon black can reach 10⁻⁶. 4 -10 5 The S / m ratio is 1-2 orders of magnitude higher than that of traditional carbon black.

[0022] This invention introduces specific functional groups (such as pyridine nitrogen, graphitic nitrogen, or hydroxyl groups) into the carbon black framework through in-situ doping technology, achieving precise control over surface chemical properties. These functional groups endow carbon black with ultra-high selectivity for specific molecules (such as heavy metal ions, drug molecules, or gas molecules), increasing the adsorption capacity by more than 2 times compared to the best existing products.

[0023] This invention solves the scale-up and uniformity problems in traditional preparation methods by optimizing the high-temperature reactor design and activation process parameters. The rotating flow field design ensures uniform heating of the materials during the reaction, while microwave-assisted activation achieves a synergistic effect between the activation process and carbon formation, resulting in carbon black with excellent mechanical strength and structural stability.

[0024] This invention achieves low-cost, sustainable production through innovative precursor combinations and template agent design. The utilization of waste polymer cracking oil not only reduces raw material costs but also enables high-value recycling of waste. Furthermore, the self-assembly properties of the copolymer template agent make precise control of the pore structure possible, further enhancing the product's performance and application value. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall process flow of the present invention;

[0026] Figure 2 This is a flowchart illustrating the preparation process of the precursor mixture of the present invention.

[0027] Figure 3 This is a flow chart of the pyrolysis reactor process of the present invention;

[0028] Figure 4 This is a flowchart of the activation reactor process of the present invention;

[0029] Figure 5 This is a flowchart of the surface functionalization process of the present invention. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention provides a high specific surface area special carbon black and its preparation method, the specific implementation method of which is combined with Figures 1-5 A detailed explanation will be provided. For example, Figure 1 As shown, the entire preparation process includes the preparation of the precursor mixture, pyrolysis treatment in the pyrolysis reactor, activation treatment in the activation reactor, and surface functionalization steps in the surface functionalization device. The specific composition, connection, and operating principle of each part will be described below.

[0032] like Figure 2 As shown, the precursor mixture is first prepared by mixing biomass refining products, waste polymer pyrolysis oil, and copolymer template agents in a specific ratio. The specific operation is as follows: Cellulose nanocrystals or lignin-derived aromatic compounds treated with delignification are used as biomass refining products and mixed with tire pyrolysis oil that has undergone selective enrichment of aromatic components at a weight ratio of 4-6:3-5. Then, a self-assembled copolymer with a block structure is added as a copolymer template agent, with a weight ratio of 4-6:3-5:1-2. Under inert gas protection, the above raw materials are added to an organic solvent, preferably dimethyl sulfoxide or N,N-dimethylformamide, at an amount 5-10 times the total weight of the precursor mixture. The mixture is heated to 60-80°C and stirred until a homogeneous precursor solution is formed. In this process, the organic solvent ensures that the raw materials are fully dissolved and uniformly dispersed, while the copolymer template agent, through its self-assembly characteristics of its block structure, forms a preliminary pore template framework in the solution, laying the foundation for the multi-level pore structure in the subsequent pyrolysis process.

[0033] like Figure 3As shown, the precursor solution is then transferred to a pyrolysis reactor for prepolymerization and pyrolysis. In the pyrolysis reactor, the precursor solution is first mixed with a catalyst, which is selected from iron oxide nanoparticles or nickel oxide nanoparticles with a particle size range of 10-50 nm, and its addition amount is 5-10% of the weight of the precursor mixture. The mixture is then heated to 80-100℃ for prepolymerization for 1-2 hours. During this process, the catalyst promotes the cross-linking reaction between precursor molecules, forming a gel-like intermediate. The formation of the gel-like intermediate indicates that the precursor solution has transformed into a solid framework structure with a certain mechanical strength, which contains a preliminary network of pores formed by the copolymer template agent. The gel-like intermediate is then placed in a high-temperature reactor and heated to 700-900℃ at a heating rate of 10-20℃ / min under a nitrogen atmosphere, and held for 2-4 hours for pyrolysis. The high-temperature reactor employs a rotating flow field design with internal spiral guide plates, and the inner wall of the reactor is coated with a silicon carbide coating to enhance heat transfer efficiency. The rotating flow field design ensures uniform heating of the material during the reaction, avoiding structural collapse caused by localized overheating. Simultaneously, the spiral guide plate guides the material along a specific path, further improving the uniformity of the pyrolysis reaction. After pyrolysis, cooling to room temperature yields primary carbon material.

[0034] like Figure 4 As shown, the primary carbon material is then transferred to an activation reactor for activation. The activation reactor employs microwave-assisted heating technology, activating the primary carbon material at a frequency of 2.45 GHz and a power of 500-800 W. During activation, the primary carbon material is mixed with an activating agent, which may be water vapor, carbon dioxide, or potassium hydroxide vapor, at a flow rate of 100-300 mL / min. The activation temperature is 800-1000℃, and the activation time is 30-60 minutes. Microwave-assisted activation technology achieves a synergistic effect between the activation process and carbon formation. The rapid penetration of microwave energy enables the activating agent to react efficiently with the surface of the primary carbon material, thereby generating numerous micropores, mesopores, and macropores on the carbon material surface. After activation, the material is cooled to room temperature to obtain a high specific surface area specialty carbon black. At this point, the multi-level porous structure of carbon black consists of 40-50% micropores, 30-40% mesopores, and 10-20% macropores. This structural design not only maximizes the exposed surface area but also improves the mass transfer characteristics, enabling it to exhibit excellent performance in adsorption and catalytic applications.

[0035] like Figure 5As shown, the high specific surface area specialty carbon black is finally transferred to a surface functionalization device for surface functionalization treatment. In the device, the high specific surface area specialty carbon black is dispersed in an organic solvent, preferably ethanol or isopropanol, at an addition amount of 20-30 times its weight. Subsequently, a dopant is added, preferably a nitrogen-containing, oxygen-containing, or sulfur-containing compound, specifically urea, ammonium nitrate, or ammonium sulfate, at an addition amount of 5-15% of the carbon black's weight. Under inert gas protection, the mixture is heated to 120-150°C and stirred for 4-6 hours. After cooling, it is separated, washed, and dried to obtain the surface-functionalized specialty carbon black. During this process, the dopant reacts chemically with the carbon black surface, introducing specific functional groups such as pyridine nitrogen, graphitic nitrogen, or hydroxyl groups. These functional groups endow the carbon black with an ultra-high selective adsorption capacity for specific molecules such as heavy metal ions, drug molecules, or gas molecules.

[0036] The connections and coordination between the various components in the above steps are as follows: The precursor mixture is uniformly dispersed using a stirring device, and then the resulting precursor solution is transferred to a pyrolysis reactor for pre-polymerization and pyrolysis. The rotating flow field design and helical guide plates of the pyrolysis reactor ensure uniform heating of the materials during pyrolysis, while the silicon carbide coating improves the reactor's heat transfer efficiency. After pyrolysis, the primary carbon material is transferred to an activation reactor. The activation reactor utilizes microwave-assisted heating technology to achieve a synergistic effect between the activation process and carbon formation, thereby generating a multi-level porous structure. Finally, the activated high specific surface area special carbon black is transferred to a surface functionalization device, where the surface chemical properties are precisely controlled through the introduction of dopants. Throughout the entire preparation process, each step is closely connected through material transfer, ensuring the continuity and stability of the process.

[0037] Throughout the entire process, the composition and proportions of the precursor mixture determine the basic structure and performance of the final product. The optimized design of the pyrolysis reactor improves the uniformity of the pyrolysis process, while the microwave-assisted activation technology significantly enhances the activation efficiency. The surface functionalization device achieves precise control of surface chemical properties through in-situ doping technology. Through the synergistic effect of these steps, this invention successfully prepares a product with a specific surface area as high as 2000-2500 m². 2 High specific surface area specialty carbon black with a conductivity of 10 / g 4 -10 5 With an adsorption capacity of S / m that is more than twice that of the best existing products, it also has excellent mechanical strength and structural stability.

[0038] To enable those skilled in the art to fully understand and implement this invention, the specific implementation principles of this invention are further supplemented below in conjunction with specific application scenarios.

[0039] In practice, the preparation of the precursor mixture must be closely integrated with the operation of the pyrolysis reactor. After the biomass refining products, waste polymer pyrolysis oil, and copolymer template agent are uniformly dispersed using a stirring device, the resulting precursor solution is transferred to the pyrolysis reactor. The rotating flow field design of the pyrolysis reactor ensures uniform heating of the materials under high-temperature conditions, while the spiral guide plate guides the materials along a specific path, preventing localized overheating that could lead to the collapse of the carbon black framework structure. This design, enhanced by a silicon carbide coating, allows the pyrolysis reaction to proceed efficiently within a temperature range of 700-900℃. During this process, catalyst iron oxide or nickel oxide nanoparticles play a crucial role. With a particle size range of 10-50 nm, they effectively promote the cross-linking reaction between precursor molecules, forming a gel-like intermediate. This intermediate not only possesses a certain mechanical strength but also retains the preliminary porous network formed by the self-assembly of the copolymer template agent, laying the foundation for subsequent activation treatment.

[0040] Subsequently, the primary carbon material is transferred to an activation reactor for microwave-assisted activation. The activation reactor employs microwave heating technology at a frequency of 2.45 GHz and a power of 500-800 W. The rapidly penetrating microwave energy enables the activator (such as water vapor, carbon dioxide, or potassium hydroxide vapor) to react efficiently with the surface of the primary carbon material. This process generates a large number of micropores, mesopores, and macropores, with micropores accounting for 40-50%, mesopores for 30-40%, and macropores for 10-20%. The hierarchical pore structure design significantly increases the specific surface area of ​​the carbon black and improves its mass transfer characteristics. For example, in adsorption applications, this structure can provide more active sites while reducing diffusion resistance, thereby improving adsorption efficiency.

[0041] In surface functionalization devices, high-specific-surface-area specialty carbon black is dispersed in an organic solvent and chemically modified with dopants. Dopants such as urea, ammonium nitrate, or ammonium sulfate react with the carbon black surface at 120-150°C, introducing functional groups such as pyridine nitrogen, graphitic nitrogen, or hydroxyl groups. The presence of these functional groups alters the surface chemistry of the carbon black, enabling it to exhibit ultra-high selective adsorption capacity for specific molecules (such as heavy metal ions, drug molecules, or gas molecules). For example, in wastewater treatment scenarios, carbon black containing pyridine nitrogen can efficiently adsorb heavy metal ions, while carbon black containing hydroxyl groups has a stronger affinity for organic pollutants.

[0042] Throughout the entire process, the connections and synergies between each step are particularly important. The composition and proportions of the precursor mixture determine the basic structure of the final product; the optimized design of the pyrolysis reactor improves the uniformity of the pyrolysis process; microwave-assisted activation technology in the activation reactor significantly enhances activation efficiency; and the surface functionalization device achieves precise control of surface chemical properties through in-situ doping technology. For example, in battery applications, this high specific surface area specialty carbon black, due to its excellent conductivity and mechanical strength, can serve as a high-performance electrode material, significantly improving the energy density and cycle life of batteries.

[0043] Through the synergistic effect of the above steps, this invention successfully prepared a material with a specific surface area as high as 2000-2500 m². 2 High specific surface area specialty carbon black. This carbon black not only possesses excellent electrical conductivity (reaching 10... 4 -10 5 The graphene adsorption capacity (S / m) is more than twice that of the best existing product, while also exhibiting excellent mechanical strength and structural stability. These properties are achieved through the design of a hierarchical porous structure, the introduction of ultrathin graphene sheets or nanosheets, and the precise control of surface functional groups.

[0044] All content not described in detail in this specification is prior art known to those skilled in the art, and the model parameters of each device are not specifically limited; conventional equipment can be used. Electrical control components not mentioned in this technical solution are not shown in the figures because they are prior art, and will not be described further here.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A special carbon black with high specific surface area, characterized in that, It is obtained by pyrolysis and activation treatment of 80-120 parts by weight of precursor mixture, 5-10 parts by catalyst and 15-25 parts by template agent; The precursor mixture comprises, by weight, 40-60 parts of biomass refining product, 30-50 parts of waste polymer pyrolysis oil, and 10-20 parts of copolymer template agent; The biomass refining product is cellulose nanocrystals or lignin-derived aromatic compounds that have undergone delignification treatment; the waste polymer pyrolysis oil is tire pyrolysis oil that has undergone selective enrichment of aromatic hydrocarbon components; and the copolymer template agent is a self-assembled copolymer with a block structure.

2. The special carbon black with high specific surface area according to claim 1, characterized in that, The catalyst is iron oxide nanoparticles or nickel oxide nanoparticles with a particle size range of 10-50 nm, and the amount added is 5-10% of the weight of the precursor mixture.

3. The special carbon black with high specific surface area according to claim 1, characterized in that, The pyrolysis treatment is carried out under a nitrogen atmosphere, with a heating rate of 10-20℃ / min, a pyrolysis temperature of 700-900℃, and a holding time of 2-4 hours.

4. The special carbon black with high specific surface area according to claim 1, characterized in that, The activation process employs microwave-assisted heating technology, with a microwave frequency of 2.45 GHz, a power of 500-800 W, an activation temperature of 800-1000 ℃, and an activation time of 30-60 minutes. The activating agent is selected from water vapor, carbon dioxide, or potassium hydroxide vapor, with a flow rate of 100-300 mL / min.

5. The special carbon black with high specific surface area according to claim 1, characterized in that, The weight ratio of the copolymer template agent to the biomass refining product and waste polymer pyrolysis oil is 1-2:4-6:3-5.

6. A method for preparing high specific surface area special carbon black according to any one of claims 1 to 5, characterized in that, Includes the following steps: Under inert gas protection, the biomass refining product is mixed with waste polymer pyrolysis oil, added to an organic solvent, heated to 60-80℃ and stirred to dissolve, to obtain a uniform precursor solution; the organic solvent is dimethyl sulfoxide or N,N-dimethylformamide, and the amount added is 5-10 times the weight of the precursor mixture. The precursor solution is mixed with the copolymer template agent, a catalyst is added, and the temperature is raised to 80-100℃ to carry out a prepolymerization reaction to form a gel-like intermediate. The gel-like intermediate was placed in a high-temperature reactor and heated to 700-900℃ at a heating rate of 10-20℃ / min under a nitrogen atmosphere. The temperature was maintained for 2-4 hours to carry out the pyrolysis reaction. After cooling, the primary carbon material was obtained. Primary carbon material is mixed with an activator and placed in a microwave-assisted reactor for activation treatment at a frequency of 2.45 GHz and a power of 500-800 W for 30-60 minutes. After cooling, a special carbon black with a high specific surface area is obtained.

7. The method for preparing a special carbon black with high specific surface area according to claim 6, characterized in that, The high-temperature reactor adopts a rotating flow field design, with a spiral guide plate inside and a silicon carbide coating on the inner wall of the reactor.

8. A method for surface functionalizing high specific surface area specialty carbon black according to any one of claims 1 to 5, characterized in that, Includes the following steps: Under inert gas protection, high specific surface area special carbon black is dispersed in an organic solvent, dopant is added, the temperature is raised to 120-150℃ and stirred for 4-6 hours, and after cooling, it is separated, washed and dried to obtain surface-functionalized special carbon black. The organic solvent is ethanol or isopropanol, and the amount added is 20-30 times the weight of the high specific surface area special carbon black. The dopant is urea, ammonium nitrate or ammonium sulfate, and the amount added is 5-15% of the weight of high specific surface area special carbon black.

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