Preparation method of zinc-based n, p co-doped porous carbon material and application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QUZHOU UNIV
- Filing Date
- 2026-04-23
- Publication Date
- 2026-07-03
AI Technical Summary
Existing solid adsorbents for flue gas desulfurization suffer from problems such as low specific surface area, weak or insufficient interaction with SO2, making it difficult to achieve efficient deep removal of SO2.
A method for preparing zinc-based N,P co-doped porous carbon materials was adopted. A polymer precursor was formed by the chelation reaction of chitosan with zinc and phosphorus sources. High-temperature calcination was used to form a hierarchical porous structure. Zinc ions served as SO2 adsorption sites, and the synergistic effect of N and P atoms optimized the surface chemical properties of the material.
It achieves high specific surface area and stable adsorption performance. The material exhibits excellent SO2 adsorption capacity and stability in complex industrial flue gas, reducing operating costs and material replacement frequency, and has good resistance to impurity interference.
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Figure CN122321795A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of porous carbon material preparation technology, specifically relating to a method for preparing zinc-based N,P co-doped porous carbon materials and their applications. Background Technology
[0002] Sulfur dioxide (SO2) is a non-flammable, colorless, and toxic gas with a pungent odor, widely considered one of the main components of air pollution. Adsorption is a core technology for industrial waste gas purification, offering advantages such as high removal efficiency, low energy consumption, and simple operation. Among these, solid adsorption desulfurization technology is one of the mainstream technologies for SO2 removal from flue gas. This technology relies on the physical and chemical interactions between solid adsorbents and SO2 molecules, anchoring SO2 to the pores or surface active sites of the adsorbent to achieve SO2 separation and removal. Furthermore, the adsorbent can be regenerated through simple operations such as heating and depressurization, making it recyclable.
[0003] Currently used solid adsorbents have many technical defects: metal oxide adsorbents have strong interaction with SO2, but low specific surface area, which limits the improvement of adsorption capacity; zeolite molecular sieves have regular pores, but the active sites of metal ions are easily blocked, resulting in weak interaction with SO2 and poor desulfurization performance; carbon-based materials, represented by activated carbon, have a large specific surface area and good thermal stability, and are commonly used adsorbents for low-temperature desulfurization, but their adsorption of SO2 mainly relies on physical action, which is weak and cannot achieve deep removal of trace SO2.
[0004] In summary, developing novel solid adsorbents with both high specific surface area and strong interaction with SO2 molecules to achieve deep removal of SO2 from industrial flue gas is a pressing technical challenge in the field of flue gas desulfurization. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing and applying zinc-based N,P co-doped porous carbon materials, thereby solving the aforementioned technical problems in the prior art.
[0006] The objective of this invention can be achieved through the following technical solutions: A method for preparing a zinc-based N,P co-doped porous carbon material includes the following steps: S101. Preparation of chitosan solution: Dissolve chitosan in an aqueous acetic acid solution and stir until uniformly dissolved to form a chitosan solution with a mass content of 2-20%. S201. Preparation of sol compound: Add zinc source and phosphorus source to the chitosan solution in S101, and stir continuously at room temperature to promote the polydentate coordination chelation reaction between zinc ions, phosphate groups and amino and hydroxyl groups on the chitosan molecular chain to form a uniform sol compound. The amount of zinc source added is 1 to 5 times the mass of chitosan added, and the amount of phosphorus source added is 10 to 80% of the mass of chitosan added. S301, Preparation of polymer precursor: The sol compound of S201 is transferred to a drying device for heat treatment to remove moisture and volatile solvents, and a solid polymer precursor is obtained. S401, High-temperature calcination: The polymer precursor obtained by S301 is placed in a tube furnace and subjected to a high-temperature calcination process under an inert atmosphere. The temperature is raised to 600-1200℃ under the condition of a heating rate of 1-10℃ / min and calcined for 1-10 hours. After cooling to room temperature, zinc-based N,P co-doped porous carbon material is obtained after washing and drying. The zinc-based N,P co-doped porous carbon materials prepared have a specific surface area of 551–930 m². 2 / g, total pore volume is 0.32~0.51 cm³ 3 / g.
[0007] Furthermore, in S101, the molecular weight of the chitosan is 100,000 to 300,000.
[0008] Further, in S101, the mass fraction of the acetic acid aqueous solution is 5%; and the mass content of chitosan is a chitosan solution of 4-10%.
[0009] Furthermore, in S201, the zinc source is one or a mixture of several of anhydrous zinc chloride, zinc iodide, zinc bromide, zinc sulfate, zinc nitrate hexahydrate, zinc hydroxide, zinc gluconate, and zinc citrate.
[0010] Furthermore, in S201, the phosphorus source is one or a mixture of phosphoric acid, phytic acid, and triphenylphosphine.
[0011] Furthermore, in S301, the drying temperature is 85°C.
[0012] Furthermore, in step S301, drying is performed at a temperature of 80~90°C.
[0013] Furthermore, in S401, the inert atmosphere is the heating operation performed under a nitrogen atmosphere.
[0014] Furthermore, in S401, the temperature is raised to 600-1000℃ under the condition of controlling the heating rate at 2-3℃ / min, and calcined for 3-6 hours.
[0015] Furthermore, its application in the adsorption and removal of SO2 in industrial flue gas.
[0016] The beneficial effects of this invention are: 1. The preparation method of the present invention uses chitosan as a carbon source and nitrogen source. It utilizes the abundant nitrogen and oxygen atoms in its molecular structure to form a polymer precursor through chelation with zinc and phosphorus sources. This can achieve highly uniform dispersion of active components such as Zn, N, and P, which is beneficial for constructing porous carbon adsorbents with dense and uniformly distributed sites. At the same time, the synergistic effect of heteroatoms significantly optimizes the surface chemical properties and acid-base characteristics of carbon materials.
[0017] 2. The preparation method of the present invention utilizes the pore-forming effect generated by the volatilization of Zn component during the high-temperature carbonization process of the precursor and the synergistic pore-forming effect of the gas generated by the pyrolysis of P and N components, so that the material forms a well-developed microporous-mesoporous multi-level pore structure and a high specific surface area.
[0018] 3. The preparation method of the present invention uses Zn ions as highly efficient adsorption sites for SO2 adsorption. In carbon materials, Zn ions are coordinated and anchored by N and P heteroatoms, which improves the stability of the metal adsorption sites and exhibits excellent adsorption performance and high stability during SO2 adsorption.
[0019] 4. The preparation process of this invention is simple, the raw materials are widely available, and it is environmentally friendly. Chitosan, as an extract from marine biomass waste, has the advantages of low cost, renewability, and high nitrogen content. The material can be prepared through a simple sol-gel and one-step calcination method, without the need for complex loading or post-processing steps, and has good prospects for industrial application. At the same time, the material exhibits high adsorption capacity and excellent regeneration performance, effectively reducing the operating costs and material replacement frequency in industrial desulfurization processes.
[0020] 5. The material prepared by this invention possesses excellent structural toughness. The co-doping of P and N atoms strengthens the connections between carbon layers, ensuring that the pore structure does not collapse and active sites do not lose or become inactive when subjected to repeated "adsorption-desorption" cycles of thermal stress and chemical erosion. This long-term stability guarantees that the material can maintain stable desulfurization efficiency when treating industrial waste gas containing complex components, solving the technical pain point of easy deactivation of existing carbon-based adsorbents under complex operating conditions. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.
[0022] Figure 1 These are nitrogen adsorption-desorption curves of zinc-based N,P co-doped porous carbon materials Zn-NPC-600, Zn-NPC-800, and Zn-NPC-1000, as described in embodiments of the present invention. Figure 2 These are the X-ray diffraction patterns of zinc-based N,P co-doped porous carbon materials Zn-NPC-600, Zn-NPC-800, and Zn-NPC-1000 according to embodiments of the present invention. Figure 3 These are Fourier transform infrared spectra of zinc-based N,P co-doped porous carbon materials Zn-NPC-600, Zn-NPC-800, and Zn-NPC-1000 according to embodiments of the present invention. Figure 4 The SO2 adsorption isotherms of the zinc-based N,P co-doped porous carbon materials Zn-NPC-600, Zn-NPC-800, and Zn-NPC-1000 in the embodiments of the present invention at 25°C are shown. Figure 5 This is a schematic diagram of an evaluation device for the SO2 adsorption performance of zinc-based N,P co-doped porous carbon materials according to an embodiment of the present invention. Detailed Implementation
[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0024] This invention provides a method for preparing zinc-based N,P co-doped porous carbon materials, comprising the following steps: S101. Preparation of chitosan solution: Dissolve chitosan in a 5% (w / w) aqueous solution of acetic acid and stir until uniformly dissolved (mechanical stirring promotes the full extension and uniform dissolution of chitosan molecular chains in the acidic medium). During the dissolution process, the amino groups on the chitosan molecular chains are protonated, and the repulsive force between charges causes the polymer chain segments to change from a coiled state to an extended state, providing a spatial basis for the uniform insertion of subsequent metal ions and phosphorus source molecules, forming a chitosan solution with a chitosan content of 2-20% (transparent and with a certain viscosity). The dissolution process of chitosan is crucial for constructing a homogeneous precursor. Acetic acid, as a weak acid, provides protons to promote the protonation of amino groups without disrupting the chitosan backbone structure. Controlling the molecular weight of chitosan between 100,000 and 300,000 ensures a suitable solution viscosity. If the molecular weight is too low, the resulting sol-network structure will lack strength, easily leading to carbon skeleton collapse after calcination; if the molecular weight is too high, the solution will be too viscous, hindering the diffusion of zinc and phosphorus source molecules and resulting in uneven component distribution. Maintaining a 5% acetic acid mass fraction ensures a pH environment conducive to subsequent coordination reactions.
[0025] S201. Preparation of sol compound: Add zinc and phosphorus sources to the chitosan solution in S101, and stir continuously at room temperature to promote the polydentate coordination chelation reaction between zinc ions, phosphate groups, and amino and hydroxyl groups on the chitosan molecular chain, forming a homogeneous sol compound. The zinc source is selected from one or a mixture of several of anhydrous zinc chloride, zinc iodide, zinc bromide, zinc sulfate, zinc nitrate hexahydrate, zinc hydroxide, zinc gluconate, and zinc citrate; the phosphorus source is selected from one or a mixture of several of phosphoric acid, phytic acid, and triphenylphosphine. The following examples contain some of these components, but the above generalizations are all within the scope of protection of this application. The amount of zinc source added is set to 1-5 times the mass of chitosan, and the amount of phosphorus source added is 10-80% of the mass of chitosan. In this step, zinc ions act as metal centers, and their coordination with chitosan achieves atomic-level dispersion of the metal components. Simultaneously, phosphorus source molecules (such as phytic acid with six phosphate groups) act as crosslinking agents. The order of addition of zinc and phosphorus sources, as well as the stirring intensity, significantly affect the product performance. It is generally recommended to add the zinc source first and stir until completely transparent, then slowly add the phosphorus source dropwise. This is because zinc ions coordinate with amino groups relatively quickly, while phosphorus sources (such as phytic acid) have multiple functional groups, easily causing instantaneous cross-linking and local precipitation in the solution. Continuous mechanical stirring promotes the coordination equilibrium to shift towards the formation of a uniform three-dimensional network. The ratio of zinc source to chitosan mass is controlled at 1-5 times to balance the pore-forming effect and the framework strength; when the zinc source ratio is too high, excessive volatilization weakens the mechanical strength of the carbon material; when the ratio is too low, the resulting porosity is insufficient to support high-capacity adsorption. The chitosan long chain is further locked by hydrogen bonds and coordination bonds to form a highly stable three-dimensional network structure. This molecular-level component arrangement eliminates the inhomogeneity caused by macroscopic mixing and ensures the high dispersion of heteroatoms during the subsequent carbonization process.
[0026] S301. Preparation of polymer precursor: The sol compound of S201 is placed in a forced-air drying oven and dried at 80-90℃ to remove moisture and volatile solvents, obtaining a solid polymer precursor. The drying time is determined by the complete removal of moisture. During the drying process, the sol network shrinks, and zinc, phosphorus, and nitrogen elements are tightly locked in the polymer matrix, forming a highly uniform hybrid precursor, laying the material basis for in-situ doping in the subsequent high-temperature carbonization process.
[0027] S401, High-Temperature Calcination: The polymer precursor obtained in S301 is placed in a tube furnace and subjected to a high-temperature calcination process under an inert atmosphere. The choice of heating rate directly affects the microstructure of the carbon material. Heating to 600-1200℃ at a controlled heating rate of 1-10℃ / min for 1-10 hours is beneficial for the stable discharge of volatiles and prevents large cracks in the carbon skeleton due to violent gas production. Calcination temperature is a core parameter determining material properties. In the 600-800℃ range, carbonization and initial pore formation mainly occur. When the temperature rises to 800-1000℃, zinc reduction and volatilization reach their peak, the specific surface area increases significantly, and the doping efficiency of P and N atoms is highest at this temperature, resulting in the most stable active sites. If the temperature exceeds 1200℃, the carbon material is prone to excessive graphitization, leading to pore shrinkage, and the active sites may be deactivated due to high-temperature sintering. Therefore, by precisely controlling the calcination temperature, both the specific surface area and the density of chemically active sites were optimized. During calcination, the chitosan framework undergoes dehydration, decarbonylation, and aromatization reactions, gradually transforming into a disordered graphite structure. Simultaneously, nitrogen elements are in-situ embedded in the carbon lattice, forming active sites such as pyridine nitrogen, pyrrole nitrogen, and graphitic nitrogen. Phosphorus elements, through covalent bonding with carbon atoms, form phosphate esters or phosphonic acid groups on the carbon surface, regulating the surface acid-base distribution of the carbon material. After cooling to room temperature, washing, and drying, zinc-based N,P co-doped porous carbon materials are obtained.
[0028] During high-temperature calcination, the zinc component plays a crucial role in pore formation and activation. When the temperature rises to near the reduction and volatilization temperature of zinc, zinc species undergo in-situ reduction within the carbon matrix. The generated metallic zinc vapor penetrates the carbon framework during its outward diffusion, creating numerous micropores and mesopores. This "self-templating" pore-forming effect not only significantly increases the specific surface area of the material but also, due to the uniform overflow of zinc vapor, results in highly interconnected channels. The chemical behavior of the zinc source at high temperatures promotes the formation of a multi-level pore system in the carbon material, with micropores for adsorption and mesopores for diffusion.
[0029] The interaction mechanism of its components is further explained in detail below: Chitosan, as a structural building block, contains numerous amino (-NH2) and hydroxyl (-OH) groups in its molecular structure. In acetic acid solution, these functional groups exhibit strong nucleophilicity, enabling them to coordinate with positively charged zinc ions. The zinc ion acts as a bridging center, bringing different chitosan molecular chains together. Simultaneously, phosphorus source molecules such as phytic acid contain multiple phosphate groups, each capable of coordinating with metal ions or forming hydrogen bonds with amino groups. This many-to-many interaction constructs an extremely complex cross-linked network in solution. During the subsequent drying process, as the solvent evaporates, this network structure is locked in the solid phase, forming an atomically mixed polymer precursor.
[0030] During the calcination stage, this atomically mixed state transforms into a unique doped structure. Nitrogen atoms, originating from the chitosan framework, tend to occupy the edges or vacancies of the graphene lattice during carbonization, forming pyridine nitrogen (N-6) and pyrrole nitrogen (N-5). These nitrogen atoms possess lone pairs of electrons, significantly enhancing the basicity of the carbon surface and acting as electron donors to strengthen the attraction to sulfur dioxide (electron acceptors). The introduction of phosphorus atoms, due to their large atomic radius, creates a spreading effect between carbon layers, facilitating the formation of more micropores. More importantly, the strong electronic interaction between phosphorus and zinc atoms forms Zn-P bonds that effectively suppress zinc aggregation at high temperatures, allowing zinc to disperse on the carbon surface in extremely small sizes, thus exposing more active sites.
[0031] Example 1 This embodiment provides a method for preparing a zinc-based N,P co-doped porous carbon material, including the following steps: S1. Dissolve 3.0 g of chitosan in 60.0 g of 5% acetic acid aqueous solution until homogeneous to form a 5% chitosan solution. S2. Then, add 6.0 g of zinc chloride and 1.5 g of phytic acid to the chitosan solution and continue stirring to form a homogeneous sol compound. S3. Place the mixture in a forced-air drying oven and dry it at 85 °C to form a polymer precursor; S4. Place the polymer precursor in a tube furnace, set the heating rate to 3 ℃ / min, raise it to 600 ℃ and hold for 3 hours. After the tube furnace cools down to room temperature, take out the sample to obtain a zinc-based P,N co-doped porous carbon material, named Zn-NPC-600.
[0032] The specific surface area of the prepared Zn-NPC-600 carbon material is 551 m². 2 / g, Zn-NPC-600 was used for SO2 adsorption (refer to...) Figure 5 The device, under standard atmospheric pressure (1.0 bar) and 25 °C, showed an adsorption capacity of 9.2 mmol / g for Zn-NPC-600. (Reference) Figure 4 The adsorption isotherm in the figure shows that Zn-NPC-600 exhibits a faster adsorption rate in the low-pressure region.
[0033] Example 2 This embodiment provides a method for preparing a zinc-based N,P co-doped porous carbon material, including the following steps: S1. Dissolve 3.0 g of chitosan in 60.0 g of 5% acetic acid aqueous solution until homogeneous to form a 5% chitosan solution. S2. Then, add 6.0 g of zinc chloride and 1.5 g of phytic acid to the chitosan solution and continue stirring to form a homogeneous sol compound. S3. Place the mixture in a forced-air drying oven and dry it at 85 °C to form a polymer precursor; S4. Place the polymer precursor in a tube furnace, set the heating rate to 3 ℃ / min, raise it to 800 ℃ and hold for 3 hours. After the tube furnace cools down to room temperature, take out the sample to obtain a zinc-based P,N co-doped porous carbon material, named Zn-NPC-800.
[0034] The prepared Zn-NPC-800 carbon material has a specific surface area of 794 m². 2 / g, see reference Figure 5 When Zn-NPC-800 was used for SO2 adsorption, the adsorption capacity was 14.6 mmol / g under standard atmospheric pressure (1.0 bar) and 25 °C. This excellent performance is attributed to the perfect balance between the density of active sites and the pore structure formed at 800 °C, and the electronic effect of heteroatoms optimizes the affinity of zinc sites for SO2 molecules.
[0035] Example 3 This embodiment provides a method for preparing a zinc-based N,P co-doped porous carbon material, including the following steps: S1. Dissolve 3.0 g of chitosan in 60.0 g of 5% acetic acid aqueous solution until homogeneous to form a 5% chitosan solution. S2. Then, add 6.0 g of zinc chloride and 1.5 g of phytic acid to the chitosan solution and continue stirring to form a homogeneous sol compound. S3. Place the mixture in a forced-air drying oven and dry it at 85 °C to form a polymer precursor; S4. Place the polymer precursor in a tube furnace, set the heating rate to 3 ℃ / min, raise it to 1000 ℃ and hold for 3 hours. After the tube furnace cools down to room temperature, take out the sample to obtain zinc-based P,N co-doped porous carbon material, named Zn-NPC-1000.
[0036] The prepared Zn-NPC-1000 carbon material, due to further increases in calcination temperature, experienced shrinkage of the carbon skeleton and significant loss of zinc components, resulting in an increased specific surface area of 930 m². 2 / g, but excessively high temperatures cause some surface active sites to sinter or restructure. When Zn-NPC-1000 was used for SO2 adsorption, under standard atmospheric pressure (1.0 bar) and 25 °C, the adsorption capacity of Zn-NPC-1000 was 12.5 mmol / g. Although it had the highest specific surface area, its total adsorption capacity was slightly lower than that in Example 2 due to the decrease in the density of chemisorption sites.
[0037] Example 4 This embodiment provides a method for preparing a zinc-based N,P co-doped porous carbon material, including the following steps: S1. Dissolve 5.0 g of chitosan in 125.0 g of 5% acetic acid aqueous solution until homogeneous to form a 4% chitosan solution. S2. Then, add 15.0 g of zinc chloride and 2.0 g of phytic acid to the chitosan solution and continue stirring to form a homogeneous sol compound. S3. Place the mixture in a forced-air drying oven and dry it at 85 °C to form a polymer precursor; S4. Place the polymer precursor in a tube furnace, set the heating rate to 2 ℃ / min, raise it to 700 ℃ and hold for 6 hours. After the tube furnace cools down to room temperature, take out the sample to obtain a zinc-based P,N co-doped porous carbon material, named Zn-NPC-700.
[0038] Extending the isothermal time facilitates the full development of the carbon structure, resulting in a Zn-NPC-700 carbon material with a specific surface area of 650 m². 2 When Zn-NPC-700 was used for SO2 adsorption, the adsorption capacity was 10.2 mmol / g under standard atmospheric pressure (1.0 bar) and 25 °C. This example demonstrates that the pore structure of the material can be effectively controlled by adjusting the zinc source ratio and calcination time.
[0039] Example 5 This embodiment provides a method for preparing a zinc-based N,P co-doped porous carbon material, including the following steps: S1. Dissolve 5.0 g of chitosan in 50.0 g of 5% acetic acid aqueous solution until homogeneous to form a 10% chitosan solution. S2. Then, add 10.0 g of zinc chloride and 2.5 g of phytic acid to the chitosan solution and continue stirring to form a homogeneous sol compound. S3. Place the mixture in a forced-air drying oven and dry it at 85 °C to form a polymer precursor; S4. Place the polymer precursor in a tube furnace, set the heating rate to 2 ℃ / min, raise it to 900 ℃ and hold for 6 hours. After the tube furnace cools down to room temperature, take out the sample to obtain a zinc-based P,N co-doped porous carbon material, named Zn-NPC-900.
[0040] The specific surface area of the prepared Zn-NPC-900 carbon material is 816 m². 2 When Zn-NPC-900 was used for SO2 adsorption, the adsorption capacity was 13.2 mmol / g under standard atmospheric pressure (1.0 bar) and 25 °C. High concentrations of chitosan formed a denser network in the precursor stage, and the carbon material formed at 900 °C exhibited excellent structural stability.
[0041] The zinc-based N,P co-doped porous carbon material prepared by the above method exhibits physicochemical properties that can be obtained by... Figure 2 To be continued Figure 4 This has been confirmed. (See attached reference.) Figure 2 The nitrogen adsorption-desorption curves of the material exhibit typical type I and type IV combined characteristics. The adsorption capacity increases rapidly in the low-pressure region, demonstrating the presence of numerous micropores, while the hysteresis loops appearing in the medium- and high-pressure regions confirm the well-developed mesoporous structure. This multi-level pore system, with its coexistence of micropores and mesopores, provides a large internal surface area to accommodate sulfur dioxide molecules and reduces the diffusion resistance of gas molecules within the material. (See attached reference.) Figure 3 XRD patterns showed distinct carbon characteristic peaks in the material, and no diffraction peaks were observed for large-sized zinc crystals, confirming that zinc species are distributed with extremely high dispersion within the carbon framework. (See attached reference.) Figure 4 The characteristic vibrational peaks of CN, CP, and Zn-N appearing in the FT-IR spectrum prove that heteroatoms have been successfully integrated into the carbon matrix and formed a stable chemical bonding environment.
[0042] At the application level, the sulfur dioxide capture mechanism of the material in this invention involves the synergistic effect of physical diffusion, electrostatic attraction, and coordination chemisorption. The hierarchical porous structure ensures that sulfur dioxide molecules can overcome boundary layer resistance and rapidly penetrate deep into the material. Inside the micropores, sulfur dioxide molecules are initially enriched due to the overlapping potential energy of the pore walls. Subsequently, the Zn-PN active centers distributed on the pore walls form stable chemical bonds with sulfur dioxide molecules through Lewis acid-base interactions. This strong interaction ensures that even under extremely low sulfur dioxide partial pressures, the adsorption equilibrium still shifts towards the adsorbed state, thereby achieving complete removal of sulfur dioxide from flue gas.
[0043] The zinc-based N,P co-doped porous carbon material prepared also exhibits good resistance to impurity interference when treating actual industrial flue gas; industrial flue gas usually contains a high concentration of carbon dioxide (CO2) and a certain amount of nitrogen (N2).
[0044] In summary, this invention provides a high-performance, low-cost, and reliable sulfur dioxide adsorbent material and its preparation scheme through systematic optimization of raw material ratios, cross-linking processes, calcination procedures, and elemental synergistic effects. This scheme not only resolves the contradiction between adsorption capacity and stability at the technical level but also makes positive explorations in environmental protection and resource recycling, aligning with the core demands of current green chemistry and sustainable industrial development.
[0045] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.
Claims
1. A method for preparing a zinc-based N,P co-doped porous carbon material, characterized in that, Includes the following steps: S101. Preparation of chitosan solution: Dissolve chitosan in an aqueous acetic acid solution and stir until uniformly dissolved to form a chitosan solution with a mass content of 2-20%. S201. Preparation of sol compound: Add zinc source and phosphorus source to the chitosan solution in S101, and stir continuously at room temperature to promote the polydentate coordination chelation reaction between zinc ions, phosphate groups and amino and hydroxyl groups on the chitosan molecular chain to form a uniform sol compound. The amount of zinc source added is 1 to 5 times the mass of chitosan added, and the amount of phosphorus source added is 10 to 80% of the mass of chitosan added. S301, Preparation of polymer precursor: The sol compound of S201 is transferred to a drying device for heat treatment to remove moisture and volatile solvents, and a solid polymer precursor is obtained. S401, High-temperature calcination: The polymer precursor obtained by S301 is placed in a tube furnace and subjected to a high-temperature calcination process under an inert atmosphere. The temperature is raised to 600-1200℃ under the condition of a heating rate of 1-10℃ / min and calcined for 1-10 hours. After cooling to room temperature, zinc-based N,P co-doped porous carbon material is obtained after washing and drying. The zinc-based N,P co-doped porous carbon materials prepared have a specific surface area of 551–930 m². 2 / g, total pore volume is 0.32~0.51 cm³ 3 / g.
2. The method for preparing zinc-based N,P co-doped porous carbon material according to claim 1, characterized in that, In S101, the molecular weight of chitosan is 100,000 to 300,000.
3. The method for preparing zinc-based N,P co-doped porous carbon material according to claim 1, characterized in that, In S101, the mass fraction of the acetic acid aqueous solution is 5%; the mass content of chitosan is 4-10% chitosan solution.
4. The method for preparing zinc-based N,P co-doped porous carbon material according to claim 1, characterized in that, In S201, the zinc source is one or a mixture of several of anhydrous zinc chloride, zinc iodide, zinc bromide, zinc sulfate, zinc nitrate hexahydrate, zinc hydroxide, zinc gluconate, and zinc citrate.
5. The method for preparing zinc-based N,P co-doped porous carbon material according to claim 1, characterized in that, In S201, the phosphorus source is one or a mixture of phosphoric acid, phytic acid, and triphenylphosphine.
6. The method for preparing zinc-based N,P co-doped porous carbon material according to claim 1, characterized in that, In S301, the drying temperature is 85°C.
7. The method for preparing zinc-based N,P co-doped porous carbon material according to claim 1, characterized in that, In step S301, drying is performed at a temperature of 80~90℃.
8. The method for preparing zinc-based N,P co-doped porous carbon material according to claim 1, characterized in that, In step S401, the inert atmosphere is the nitrogen atmosphere used for the heating operation.
9. The method for preparing zinc-based N,P co-doped porous carbon material according to claim 1, characterized in that, In S401, the temperature is raised to 600-1000℃ under the condition of controlling the heating rate at 2-3℃ / min, and calcined for 3-6 hours.
10. The method for preparing zinc-based N,P co-doped porous carbon material according to claim 1, characterized in that, Application of adsorption and removal of SO2 in industrial flue gas.