Carbon capture material and method of making the same

Abstract

The application provides a carbon capture material and a preparation method thereof, and belongs to the technical field of carbon capture, utilization and storage. The carbon capture material comprises a composite core and a composite vesicle membrane; the composite core comprises biochar with a three-dimensional porous network structure and alkaline earth metal carbonate nanosheets arranged in the three-dimensional porous network structure in an ordered manner; the composite vesicle membrane is located on the surface of the composite core, and the composite vesicle membrane comprises, from inside to outside, a polyethyleneimine / ammonium polyphosphate layer and a tetraethyl orthosilicate / polydimethylsiloxane layer.

Description

Technical Field

[0001] This application relates to the field of carbon capture, utilization and storage technology, and in particular to a carbon capture material and its preparation method. Background Technology

[0002] Carbon capture, utilization and storage (CCDS) technology is an important means of addressing climate change. However, related carbon capture materials, especially those based on natural minerals or biochar, mainly face the following limitations: low carbon dioxide (CO2) capture capacity, poor structural stability, single function and difficulty in synergy, and difficulty in large-scale preparation and molding. These defects limit the application of carbon capture materials in large-scale environmental remediation or industrial plants. Summary of the Invention

[0003] In view of this, this application provides a carbon capture material and a method for preparing the same. This carbon capture material can combine high carbon capture efficiency, structural stability, and macroscopic engineering capability.

[0004] According to a first aspect of this application, a carbon trapping material is provided, comprising: a composite core including biochar having a three-dimensional porous network structure and alkaline earth metal carbonate nanosheets orderly arranged in the three-dimensional porous network structure; and a composite vesicle membrane located on the surface of the composite core, wherein the composite vesicle membrane comprises, from the inside out, a polyethyleneimine / ammonium polyphosphate layer and a tetraethyl orthosilicate / polydimethylsiloxane layer.

[0005] According to a second aspect of this application, a method for preparing the aforementioned carbon capture material is provided. The method includes: preparing alkaline earth metal carbonate nanosheets in a three-dimensional porous network structure of biochar to obtain biochar loaded with alkaline earth metal carbonate nanosheets; subjecting the aforementioned biochar loaded with alkaline earth metal carbonate nanosheets to a third impregnation treatment in a polyethyleneimine / ammonium polyphosphate solution and a fourth impregnation treatment in a first tetraethyl orthosilicate / polydimethylsiloxane sol to obtain a first intermediate, thereby obtaining the carbon capture material.

[0006] According to embodiments of this application, biochar with a three-dimensional porous network structure exhibits a high CO2 capture capacity. Alkaline earth metal carbonate nanosheets, orderly arranged within the three-dimensional porous network structure of the biochar, demonstrate phase stabilization and ultra-low heat flux transport characteristics similar to natural spheroids, thus providing structural stability and physical barrier properties. The composite vesicle membrane, consisting of a "flexible inner layer (polyethyleneimine / ammonium polyphosphate layer) - rigid outer shell (tetraethyl orthosilicate / polydimethylsiloxane layer)," not only stabilizes the internal composite core, preventing the agglomeration or loss of alkaline earth metal carbonate nanosheets, but also introduces flame-retardant and hydrophobic properties, and improves the mechanical strength of the carbon capture material. Furthermore, under the high temperatures of a fire, the composite vesicle membrane undergoes sequential organic deorganization, densification, and inorganic phase rearrangement, directly transforming into a ceramic-like inorganic layer on the material surface, effectively blocking the transfer of oxygen and heat to the interior.

[0007] In summary, by constructing a multi-level interlocking structure of biochar-alkaline earth metal carbonate nanosheets-composite vesicle membrane, carbon capture materials exhibit phase stabilization and ultra-low heat flux transport characteristics under extreme heat flows such as wildfires. They can form a ceramic-like inorganic layer in situ in the fire field, while capturing and mineralizing CO2 generated by combustion. Thus, the three usually independent functions of flame retardancy, structural protection and carbon fixation are coupled into one in a single material, enabling carbon capture materials to have good carbon capture efficiency, structural stability and macroscopic engineering capabilities. Attached Figure Description

[0008] The above and other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0009] Figure 1 A schematic diagram of the preparation method of the carbon capture material provided in the embodiments of this application is shown. Detailed Implementation

[0010] The embodiments of this application will be described below. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, many specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0011] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "comprising" as used herein indicates the presence of features, steps, or operations, but does not exclude the presence or addition of one or more other features.

[0012] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0013] In related technologies, carbon capture and mineralization materials, especially those based on natural minerals or biochar, mainly face the following limitations: Limited reactivity and kinetics: Insufficient specific surface area and active sites lead to low CO2 capture capacity and slow mineralization reaction rates; Poor structural stability: Under repeated temperature and humidity cycles or stress, porous structures are prone to collapse, active components are easily lost, and cycle performance is poor; Single function and difficulty in synergy: Materials typically focus on a single adsorption or mineralization process, lacking the ability to integrate the entire chain of CO2 capture, directional transport, controlled mineralization, and product stabilization and storage; Difficulty in large-scale preparation and molding: Laboratory-scale powder or granular materials are difficult to process into practical components with specific shapes and mechanical strengths, limiting their application in large-scale environmental remediation or industrial installations.

[0014] In summary, among the related technologies, solid-phase materials based on natural minerals or biochar still face core bottlenecks such as sluggish reaction kinetics, easy collapse of porous structures, and difficulty in synergizing single functions, which limit their macroscopic engineering applications in complex environments.

[0015] In the process of realizing this application, it was discovered that alkaline earth metal carbonate nanosheets can be loaded into the three-dimensional porous network structure of biochar, giving it phase stabilization and ultra-low heat flux transport characteristics similar to natural coccolith; and by constructing a multi-level interlocking structure of composite core / composite vesicle membrane from the inside out, the carbon capture material is endowed with high carbon capture efficiency and structural stability.

[0016] In view of this, an embodiment of the first aspect of this application provides a carbon trapping material comprising a composite core and a composite vesicle membrane located on the surface of the composite core. The composite core comprises biochar having a three-dimensional porous network structure and alkaline earth metal carbonate nanosheets arranged in an orderly manner within the three-dimensional porous network structure. The composite vesicle membrane comprises, from the inside out, a polyethyleneimine / ammonium polyphosphate (PEI / APP) layer and a tetraethyl orthosilicate / polydimethylsiloxane (TEOS / PDMS) layer.

[0017] In this application, alkaline earth metal carbonate nanosheets orderly arranged in a three-dimensional porous network structure can refer to alkaline earth metal carbonate nanosheets being orderly arranged on the inner walls and outer surfaces of the pores of the three-dimensional porous network structure. The alkaline earth metal carbonate nanosheets are orderly arranged in the three-dimensional porous network structure mainly through electrostatic interactions, ionic bonding, and coordination interactions.

[0018] According to embodiments of this application, biochar with a three-dimensional porous network structure has a high carbon dioxide capture capacity. Alkaline earth metal carbonate nanosheets, orderly arranged within the three-dimensional porous network structure of the biochar, exhibit phase stabilization and ultra-low heat flux transport characteristics similar to natural spheroids, thus providing structural stability and physical barrier properties. The composite vesicle membrane, consisting of a "flexible inner layer (polyethyleneimine / ammonium polyphosphate layer) - rigid outer shell (tetraethyl orthosilicate / polydimethylsiloxane layer)," not only stabilizes the internal composite core, preventing the agglomeration or loss of alkaline earth metal carbonate nanosheets, but also introduces flame-retardant and hydrophobic properties, and improves the mechanical strength of the carbon capture material. Furthermore, under the high temperatures of a fire, the composite vesicle membrane can sequentially undergo deorganization, densification, and inorganic phase rearrangement, directly transforming into a ceramic-like inorganic layer on the material surface, effectively blocking the transfer of oxygen and heat to the interior. By constructing a multi-level interlocking structure of biochar-alkaline earth metal carbonate nanosheets-composite vesicle membrane, carbon capture materials exhibit phase stabilization and ultra-low heat flux transport characteristics under extreme heat flows such as wildfires. They can form a ceramic-like inorganic layer in situ in the fire field, while capturing and mineralizing CO2 produced by combustion. This couples three usually independent processes of flame retardancy, structural protection and carbon fixation into a single material, enabling carbon capture materials to have good carbon capture efficiency, structural stability and macroscopic engineering capabilities.

[0019] Furthermore, the carbon capture material provided in this application can be transformed into a bulk material or component with good macroscopic shape, mechanical strength and flame retardant rating through hot pressing densification, which solves the bottleneck that powder materials are difficult to deploy in practice. This allows the carbon capture material to be directly used to construct carbon capture devices, field remediation modules or building flame retardant coatings, achieving a key leap from "material" to "product".

[0020] In some embodiments of this application, the biochar can be plant fiber biochar, that is, biochar can be a carbon-rich material generated by the pyrolysis of plant fibers (such as bagasse fiber, bamboo fiber, etc.) under anaerobic conditions. Plant fiber biochar uses agricultural waste (such as bagasse fiber, bamboo fiber, etc.) as the main raw material, the process has relatively low energy consumption, conforms to the concept of green chemistry and circular economy, and has potential cost advantages for large-scale production and application.

[0021] In some embodiments of this application, alkaline earth metal carbonate nanosheets may include at least one of calcium carbonate nanosheets and magnesium carbonate nanosheets. The alkaline earth metal carbonate nanosheets may be polygonal, with a side length of 50 nm to 500 nm and a thickness of 10 nm to 50 nm. Exemplarily, the alkaline earth metal carbonate nanosheets may be hexagonal, irregular polygonal, etc. The side length of the alkaline earth metal carbonate nanosheets may be within the range of any two of the following values: 50 nm, 100 nm, 150 nm, 200 nm, 300 nm, 400 nm, 500 nm, or more. The thickness of the metal carbonate nanosheets may be within the range of any two of the following values: 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, or more. The above-mentioned alkaline earth metal carbonate nanosheets have advantages such as physical barrier properties, chemical flame retardancy, smoke suppression, environmental friendliness, and low cost.

[0022] In some embodiments of this application, the mass ratio of polyethyleneimine to ammonium polyphosphate in the polyethyleneimine / ammonium polyphosphate layer can be (1~3):(2~4). Exemplarily, the mass ratio of polyethyleneimine to ammonium polyphosphate in the polyethyleneimine / ammonium polyphosphate layer can be 1:4, 1:3, 1:2, 1:1, 3:2, or any two of the above ratios. The aforementioned range of mass ratios of polyethyleneimine to ammonium polyphosphate is more conducive to forming a flexible inner layer rich in phosphorus and nitrogen flame-retardant elements on the surface of the composite core through electrostatic interaction.

[0023] In some embodiments of this application, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane in the tetraethyl orthosilicate / polydimethylsiloxane layer can be (1~3):1. Exemplarily, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane in the tetraethyl orthosilicate / polydimethylsiloxane layer can be 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, or any two of the above ratios. A mass ratio of tetraethyl orthosilicate to polydimethylsiloxane within the above range is more conducive to the formation of a robust inorganic / organic hybrid "shell" of tetraethyl orthosilicate and polydimethylsiloxane on the surface of the polyethyleneimine / ammonium polyphosphate layer.

[0024] In some embodiments of this application, the thickness of the composite vesicle membrane can be 20 nm to 100 nm. Exemplarily, the thickness of the composite vesicle membrane can be any two values ​​within the range of 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, or more. A thickness within the above range can further stabilize the internal composite core, prevent the agglomeration or loss of alkaline earth metal carbonate nanosheets, and improve the flame retardant properties, hydrophobic properties, and mechanical strength of the carbon capture material.

[0025] In some embodiments of this application, the specific surface area of ​​the carbon-capturing material can be from 450 m² / g to 600 m² / g. Exemplarily, the specific surface area of ​​the carbon-capturing material can be 450 m² / g, 480 m² / g, 500 m² / g, 520 m² / g, 550 m² / g, 580 m² / g, 600 m² / g, or any two of these values. A specific surface area within the above range can further improve the carbon dioxide capture capacity of the carbon-capturing material and facilitates the orderly arrangement of alkaline earth metal carbonate nanosheets in the three-dimensional porous network structure of biochar.

[0026] In some embodiments of this application, the pore size of the carbon trapping material can be 2 nm to 50 nm. Exemplarily, the pore size of the carbon trapping material can be within any two of the following ranges: 2 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, or more. A pore size within this range can further improve the carbon dioxide trapping capacity and facilitate the orderly arrangement of alkaline earth metal carbonate nanosheets in the three-dimensional porous network structure of biochar.

[0027] In some embodiments of this application, the carbon trapping material may further include a hydrophobic composite layer located on the surface of the composite vesicle membrane away from the composite core. The hydrophobic composite layer comprises, from the inside out, a beeswax base layer, a coconut oil intermediate layer, and a tetraethyl orthosilicate / polydimethylsiloxane superhydrophobic coating.

[0028] Based on this hydrophobic composite layer, a hydrophobic gradient with gradually increasing hydrophobicity from the inside to the outside is constructed. Thus, the carbon capture material provided in this application embodiment can integrate CO2 capture, mineralization and storage, flame retardancy and fire resistance, and superhydrophobic protection. The unique composite vesicle membrane structure and hydrophobic gradient layer enable it to adapt to complex environments (such as high temperature, high humidity, and dusty conditions after a wildfire).

[0029] In some embodiments of this application, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane in the tetraethyl orthosilicate / polydimethylsiloxane superhydrophobic coating can be (1~3):1. Within this range, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane can further improve the mechanical strength of the carbon-capturing material; under the high temperature of a fire, it can be better transformed into a ceramic-like inorganic layer, effectively blocking the transfer of oxygen and heat to the interior.

[0030] In some embodiments of this application, the carbon capture material may further include a flame-retardant layer located on the surface of the hydrophobic composite layer away from the composite vesicle membrane. The flame-retardant layer may include at least one of phytic acid and chitosan. This further improves the flame-retardant properties of the carbon capture material.

[0031] Inspired by the biomineralization mechanism of natural spheroids, this application breaks through the limitations of traditional biomimetic strategies that merely mimic morphology or crystal phases, reconstructing the unique vesicle-confined biological pathway of spheroid mineralization in a non-living system. By introducing a polyethyleneimine / ammonium polyphosphate layer and a tetraethyl orthosilicate / polydimethylsiloxane layer interface for regulation, alkaline earth metal carbonate nanosheets are induced to spontaneously assemble into a hierarchically ordered superstructure within the three-dimensional porous network structure of biochar in a closed composite vesicle membrane. This successfully couples flame retardancy, structural reinforcement, and efficient carbon fixation into a single material system. This hierarchically ordered superstructure can be understood to include micron-sized biochar with a three-dimensional porous network structure, nano-sized alkaline earth metal carbonate nanosheets arranged in an orderly manner within the three-dimensional porous network structure, and a macroscopic composite vesicle membrane encapsulating the composite core.

[0032] Specifically, an embodiment of the second aspect of this application provides a method for preparing carbon capture materials, including steps S30 and S40.

[0033] In step S30, alkaline earth metal carbonate nanosheets are prepared in the three-dimensional porous network structure of biochar to obtain biochar loaded with alkaline earth metal carbonate nanosheets.

[0034] In step S40, the biochar loaded with alkaline earth metal carbonate nanosheets is subjected to a third impregnation treatment in a polyethyleneimine / ammonium polyphosphate solution and a fourth impregnation treatment in a first tetraethyl orthosilicate / polydimethylsiloxane sol to obtain a first intermediate, so as to obtain a carbon capture material.

[0035] This application first loads alkaline earth metal carbonate nanosheets onto the three-dimensional porous network structure of biochar. The alkaline earth metal carbonate nanosheets are loaded onto the surface of biochar mainly through electrostatic interactions, ionic bonding, and coordination to form a composite core. Then, the biological pathway of vesicle confinement for spheroplast mineralization is reconstructed in the artificial material system, allowing the alkaline earth metal carbonate nanosheets to spontaneously undergo lamellar orientation, growth, and assembly in a vesicle-closed environment formed by polyethyleneimine / ammonium polyphosphate solution and tetraethyl orthosilicate / polydimethylsiloxane sol. The negatively charged biochar loaded with alkaline earth metal carbonate nanosheets and ammonium polyphosphate interact with the positively charged polyethyleneimine through electrostatic interactions to form a flexible primary "vesicle membrane" rich in phosphorus and nitrogen flame-retardant elements. Subsequently, the tetraethyl orthosilicate / polydimethylsiloxane sol hydrolyzes and condenses on its exterior to form a robust inorganic / organic hybrid "shell". This biomimetic vesicle structure (composite vesicle membrane) with a "flexible inner layer and rigid outer shell" can not only effectively stabilize the internal alkaline earth metal carbonate nanosheets and prevent them from agglomerating or being lost, thus generating the hierarchically ordered alkaline earth metal carbonate nanosheet superstructure that only natural spheroids possess, but also endow the carbon capture material with intrinsic flame retardant and mechanically reinforcing properties.

[0036] The following combination Figure 1 The preparation method of the carbon capture material provided in the embodiments of this application will be further explained.

[0037] Figure 1 The present application illustrates a method for preparing carbon capture materials according to embodiments thereof.

[0038] In some embodiments of this application, such as Figure 1 As shown, the preparation method of carbon capture material may further include step S10, which provides a method for preparing biochar.

[0039] In step S10, plant fibers are sheared, mixed, and pressed into shape to obtain a fiber precursor. Under an inert atmosphere, the fiber precursor is sequentially carbonized and pyrolyzed to obtain biochar. The fiber precursor, after sequential shearing, mixing, and pressing, has a three-dimensional open network of a biomimetic filament exoskeleton. Based on this, a programmed temperature rise process of carbonization and pyrolysis is used. First, the cellulose skeleton is stabilized and pores are initially formed during the carbonization stage to prevent the collapse of the pore structure caused by the instantaneous and violent decomposition at high temperatures. Then, during the pyrolysis stage, the pores are further expanded and connected to form a stable carbon skeleton with high specific surface area, mainly composed of mesopores. This biochar lays the physical foundation for subsequent high-density loading of active sites and the realization of confined mineralization.

[0040] In some embodiments of this application, plant fibers can be slender filaments composed of plant cells, possessing a certain strength and flexibility. Due to their wide availability, low cost, renewability, and high carbon content, they are ideal raw materials for preparing biochar. Through processes such as carbonization and pyrolysis, they can be converted into biochar with a high specific surface area, rich pore structure, and good stability. Plant fibers, according to their source, can include at least one of seed fibers, bast fibers, leaf fibers, fruit fibers, stem fibers, and root fibers. Seed fibers, such as cotton and kapok, are derived from the epidermal cells of plant seeds; bast fibers, such as flax, ramie, and jute, originate from the bast of the stem; leaf fibers, such as sisal and abaca, are derived from the leaves or leaf sheaths; fruit fibers, such as coconut shell fibers, come from the outer shell of the fruit; stem fibers, such as bamboo fibers and bagasse fibers, are derived from the stem; and root fibers, such as iris roots, originate from the plant roots. Among these, stem fibers have advantages such as wide availability, low cost, good mechanical properties, and good processability. Before step S10, the plant fibers can be pre-dried to remove moisture; the plant fibers can also be mechanically combed to optimize their structure and physicochemical properties, thereby improving the subsequent pyrolysis efficiency and the quality of biochar.

[0041] In some embodiments of this application, in step S10, such as Figure 1As shown, plant fibers can include bagasse fiber and bamboo fiber. Bagasse fiber, rich in cellulose and hemicellulose, easily forms a porous structure during pyrolysis and has a high specific surface area; bamboo fiber has a naturally slender shape and a high cellulose content, which gives the prepared biochar a more stable skeletal structure, higher mechanical strength, and abundant surface functional groups.

[0042] In some embodiments of this application, in step S10, the mass ratio of bagasse fiber to bamboo fiber can be (1~3):1. Exemplarily, the mass ratio of bagasse fiber to bamboo fiber can be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, or any two of these ratios, preferably 2:1. By mixing bagasse and bamboo fiber in a specific ratio, and then subjecting it to high-shear mixing and light compression molding, the fiber support structure in a natural biomineralization system is successfully simulated, constructing a three-dimensional network skeleton with high porosity and good interconnectivity, providing an ideal carrier and spatially confined environment for subsequent biochar formation and mineralization reactions.

[0043] In some embodiments of this application, in step S10, the rotational speed of shear mixing can be 800 rpm to 1200 rpm, and the time can be 2 min to 5 min. Exemplarily, the rotational speed of shear mixing can be any two values ​​between 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, or more, preferably 1000 rpm; the shear mixing time can be any two values ​​between 2 min, 3 min, 4 min, 5 min, or more, preferably 3 min.

[0044] In some embodiments of this application, in step S10, the pressing pressure can be 0.1 MPa to 0.3 MPa, and the temperature can be 10°C to 40°C. Exemplarily, the pressing pressure can be any two of the following values: 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, preferably 0.2 MPa. The pressing temperature can be any two of the following values: 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, or any two of the following.

[0045] Under the above-mentioned process parameters of shearing, mixing, and pressing, it is more conducive to the formation of a three-dimensional open network similar to a biomimetic filament exoskeleton by the fiber precursor.

[0046] In some embodiments of this application, in step S10, the inert atmosphere can refer to a gaseous environment that is chemically inert and will not react chemically with reactants or products. For example, the inert atmosphere may include at least one of nitrogen, argon, and helium.

[0047] In some embodiments of this application, in step S10, carbonization can be performed by heating to 300°C to 400°C at a rate of 3°C / min to 8°C / min and holding at that temperature for 1 hour to 3 hours. Exemplarily, carbonization can be performed by heating at a rate between any two of the following values: 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, to a temperature between any two of the following values: 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, and holding at that temperature for 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, or more. Preferably, carbonization can be performed by heating to 350°C at a rate of 5°C / min and holding at that temperature for 2 hours.

[0048] In some embodiments of this application, in step S10, pyrolysis can be performed by heating to 650°C to 750°C at a rate of 8°C / min to 12°C / min and holding at that temperature for 1 hour to 3 hours. Exemplarily, pyrolysis can be performed at a rate between any two values ​​of 8°C / min, 9°C / min, 10°C / min, 11°C / min, 12°C / min, or higher, and the temperature can be increased to any two values ​​of 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, or higher, and the temperature can be held at that temperature for 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, or higher. Preferably, pyrolysis can be performed by heating to 700°C at a rate of 10°C / min and holding at that temperature for 2 hours.

[0049] This invention employs a two-stage programmed temperature rise process of "low-temperature pre-carbonization - high-temperature deep pyrolysis." First, at a lower temperature, the cellulose skeleton is stabilized and initial pores are formed, preventing the collapse of the pore structure caused by rapid and intense decomposition at high temperatures. Then, at a higher temperature, the pores are further expanded and interconnected, forming a stable carbon skeleton dominated by mesoporous structures and with a high specific surface area. This lays the physical foundation for subsequent high-density loading of active sites and confined mineralization. This step precisely controls the chemical (preserving oxygen-containing functional groups) and physical structure of the biochar carbon skeleton, providing an ideal carrier for subsequent functionalization.

[0050] This application does not have special requirements for the equipment used for carbonization and pyrolysis, as long as it can achieve the purpose of this application. For example, Figure 1 As shown, the fiber precursor can be carbonized and pyrolyzed sequentially in a tube furnace to obtain biochar.

[0051] Biochar is obtained by sequentially carbonizing and pyrolyzing the fiber precursor and then naturally cooling it. The resulting biochar has a specific surface area of ​​450 m² / g to 600 m² / g, and has a hierarchical pore structure dominated by mesopores with high porosity.

[0052] In some embodiments of this application, such as Figure 1 As shown, the preparation method of carbon capture material may further include step S20.

[0053] In step S20, before preparing alkaline earth metal carbonate nanosheets in the three-dimensional porous network structure of biochar, the biochar is subjected to acid washing and oxidation treatments sequentially. Acid washing and oxidation treatments increase the oxygen-containing functional groups and hydrophilicity on the surface of the biochar, enhancing its subsequent interaction with biomimetic acidic template molecules.

[0054] In step S20, acid washing includes reflux treatment of biochar in an acidic solution.

[0055] In some specific embodiments of this application, the acidic solution may include at least one of nitric acid and hydrochloric acid, preferably the acidic solution includes nitric acid and hydrochloric acid. The concentration of the acidic solution may be 0.5~2.0 mol / L, preferably 1 mol / L. Exemplarily, the concentration of the acidic solution may be within the range of any two of the following values: 0.5 mol / L, 0.8 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, 1.8 mol / L, 2.0 mol / L, or above. When the acidic solution includes nitric acid and hydrochloric acid, the volume ratio of nitric acid to hydrochloric acid in the acidic solution may be (1~2):(1~2), preferably 1:1. Exemplarily, when the acidic solution includes nitric acid and hydrochloric acid, the volume ratio of nitric acid to hydrochloric acid in the acidic solution may be within the range of any two of the following ratios: 1:2, 1.5:2, 1:1, 1.5:2, 2:1, or above. By refluxing the mixed acid of nitric acid and hydrochloric acid, the oxygen-containing functional groups and hydrophilicity of the biochar surface can be further increased.

[0056] In some specific embodiments of this application, the reflux temperature can be 60~100℃, preferably 80℃. The reflux time can be 4h~8h, for example, the reflux time can be any two values ​​between 4h, 5h, 6h, 7h, 8h or more.

[0057] For example, a 1 mol / L nitric acid / hydrochloric acid (volume ratio 1:1) mixed acid solution can be refluxed at 80°C for 6 h, and the biochar can be washed until neutral after acid washing.

[0058] In some specific embodiments of this application, step S20, the oxidation treatment may include placing the acid-washed biochar in a hydrogen peroxide solution for oxidation. Surface modification of the biochar through hydrogen peroxide oxidation can further increase the oxygen-containing functional groups and hydrophilicity of the biochar surface.

[0059] The concentration of the hydrogen peroxide solution can be 20 vol% to 40 vol%. For example, the concentration of the hydrogen peroxide solution can be any two values ​​between 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, or more, preferably 30 vol%.

[0060] In some specific embodiments of this application, in step S20, the oxidation treatment temperature can be 40℃~60℃. Exemplarily, the oxidation treatment temperature can be any two values ​​between 40℃, 42℃, 45℃, 50℃, 55℃, 58℃, and 60℃, preferably 50℃. The oxidation treatment time can be 1h~3h. Exemplarily, the oxidation treatment time can be any two values ​​between 1h, 1.2h, 1.5h, 2h, 2.5h, 2.8h, and 3h, preferably 2h.

[0061] In some embodiments of this application, such as Figure 1 As shown, step S30 may include steps S31, S32 and S33.

[0062] In step S31, the biochar is subjected to a first impregnation treatment in a biomimetic acidic template molecule solution to obtain templated biochar.

[0063] In step S32, alkaline earth metal salts are loaded into the three-dimensional porous network structure of the templated biochar to obtain biochar loaded with alkaline earth metal salts.

[0064] In step S33, the biochar loaded with alkaline earth metal salts is subjected to carbon dioxide mineralization treatment to obtain biochar loaded with alkaline earth metal carbonate nanosheets.

[0065] By first impregnating biochar in a biomimetic acidic template molecule solution, the acidic template molecules are arranged in an orderly manner in the three-dimensional porous network structure of the biochar through electrostatic and hydrogen bonding interactions, forming an ordered molecular membrane. This establishes a localized ionic field and acidic macromolecular environment similar to that of natural spheroids, providing chemical guidance for the subsequent directional coordination of alkaline earth metal ions and the orderly nucleation of alkaline earth metal carbonates. Further carbon dioxide mineralization treatment of the biochar oriented with alkaline earth metal salts can improve its CO2 capture capacity and mineralization rate.

[0066] In some specific embodiments of this application, in step S31, the biomimetic acidic template molecule can be a small molecule, oligopeptide, or polymer that mimics the function of acidic proteins / peptides in biomineralization. It uses acidic groups such as carboxyl and phosphate groups as its core, and induces the nucleation and growth of alkaline earth metal salts through chelation of metal ions, regulation of supersaturation and crystal face adsorption, to prepare alkaline earth metal salt biomimetic mineral materials. In step S31, the biomimetic acidic template molecule can be selected from at least one of short-chain polyaspartic acid and polyglutamic acid. The concentration of the biomimetic acidic template molecule solution can be 0.5wt%~2.0wt%. Exemplarily, the concentration of the biomimetic acidic template molecule solution can be 0.5wt%, 0.8wt%, 1.0wt%, 1.2wt%, 1.5wt%, 1.8wt%, 2.0wt%, or any two of the above values, preferably 1.0wt%.

[0067] In some specific embodiments of this application, in step S31, the first immersion treatment time can be 30 min to 60 min, and the temperature can be room temperature, for example, 15°C to 40°C. Exemplarily, the first immersion treatment time can be any two of the following values: 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, or more, preferably 45 min. The first immersion treatment temperature can be any two of the following values: 15°C, 18°C, 20°C, 25°C, 30°C, 35°C, 40°C, or more.

[0068] Under the time and temperature conditions of the first impregnation treatment, it is more conducive for biomimetic acidic template molecules to form an ordered molecular film in the three-dimensional porous network structure of biochar through electrostatic and hydrogen bonding interactions, that is, to form an ordered molecular film on the inner wall and outer surface of the pores of the three-dimensional porous network structure.

[0069] In some specific embodiments of this application, in step S32, the alkaline earth metal salt refers to a compound formed by alkaline earth metal cations (Group IIA element ions, such as magnesium ions, calcium ions, strontium ions, barium ions, etc.) and various anions (such as carbonate ions, sulfate ions, nitrate ions, etc.). In step S32, the alkaline earth metal salt may include at least one of calcium salts and magnesium salts. The aforementioned alkaline earth metal salts can be better loaded into the three-dimensional porous network structure of templated biochar, which is more conducive to the formation of alkaline earth metal carbonate nanosheets; the generated alkaline earth metal carbonate nanosheets have better structural stability and physical barrier properties.

[0070] In some specific embodiments of this application, when the alkaline earth metal salt includes calcium and magnesium salts, such as Figure 1As shown, step S32 includes: subjecting templated biochar to a second impregnation treatment in a calcium salt solution, and drying it to obtain calcium salt-loaded biochar; mixing the calcium salt-loaded biochar with olivine powder to obtain alkaline earth metal salt-loaded biochar. Using natural minerals (olivine powder) as the main raw material, the process has relatively low energy consumption, conforms to the concepts of green chemistry and circular economy, and possesses potential cost advantages for large-scale production and application.

[0071] A second impregnation treatment directs calcium ions to carboxyl groups and other functional groups on the biomimetic acidic template molecules, achieving uniform and high-density loading of active sites. Calcium-loaded biochar is then mixed with olivine powder to construct a multi-component mineralization reaction system consisting of biochar (carbon source and support), pre-loaded calcium ions, and olivine. Under the guidance of the subsequent biomimetic acidic template molecules and the confinement of vesicular channels, Ca... 2+ Mg 2+ With CO3 2- Ion-directed assembly spontaneously forms nanoscale, layered, ordered carbonate minerals, highly replicating the biomineralization pathway of natural spheroids.

[0072] In addition, olivine powder can also provide a silicon source, which can react with the calcium source in the calcium salt in subsequent heat treatment to generate dicalcium silicate (Mg2SiO4). This substance has high mineralization activity and is more conducive to obtaining alkaline earth metal carbonate nanosheets through carbonation reaction.

[0073] In some specific embodiments of this application, the calcium salt solution may include at least one of Ca(NO3)2 and CaCl2. The concentration of the calcium salt solution may be from 0.1 mol / L to 1.0 mol / L. Exemplarily, the concentration of the calcium salt solution may be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, or any two of the above values, preferably 0.5 mol / L. The second impregnation treatment can be performed for 12 to 36 hours, and the temperature can be room temperature, for example, 15°C to 40°C. For example, the second impregnation treatment time can be any two of the following values: 12h, 15h, 18h, 20h, 22h, 25h, 28h, 30h, 32h, 34h, 36h, preferably 24h. The second impregnation treatment temperature can be any two of the following values: 15°C, 18°C, 20°C, 25°C, 30°C, 35°C, 40°C. The olivine powder can be a finely ground powder material made from natural olivine minerals, with a particle size of less than 20μm. The drying temperature can be 100°C to 120°C, preferably 110°C. The drying time can be 10 to 14 hours, preferably 12 hours. To further improve the drying effect, the drying can be vacuum drying.

[0074] In some specific embodiments of this application, the mass ratio of calcium salt-loaded biochar to olivine powder can be (1~3):1. For example, the mass ratio of calcium salt-loaded biochar to olivine powder can be 1.0:1, 1.2:1, 1.5:1, 1.8:1, 2.0:1, 2.5:1, 2.8:1, 3.0:1 or any two of the above values, preferably 2.0:1.

[0075] This application does not particularly limit the mixing method of calcium salt-loaded biochar and olivine powder, as long as it achieves the purpose of this application. For example, such as... Figure 1 As shown, a pulverizer can be used to mix calcium-loaded biochar with olivine powder.

[0076] In some specific embodiments of this application, in step S33, such as Figure 1 As shown, the carbon dioxide mineralization treatment of biochar loaded with alkaline earth metal salts may include: heat-treating the biochar loaded with alkaline earth metal salts in an inert atmosphere containing carbon dioxide, and then carrying out a carbonation reaction in an atmosphere containing carbon dioxide and water vapor.

[0077] Inspired by the biomineralization mechanism of natural spheroids, this application breaks through the limitations of traditional biomimetic strategies that only imitate morphology or crystal phase in the preparation of carbon-capturing materials. Through a cascade mechanism of "solid-phase activation (heat treatment) - wet mineralization (carbonation reaction)," it reconstructs the unique vesicle confinement and ordered lamellar nucleation dual-layer biological pathway of spheroid mineralization in a non-living system. Specifically, heat treatment in an inert atmosphere containing carbon dioxide promotes the formation of active reaction nuclei (such as Ca2SiO4 and MgO) of alkaline earth metal salts, constructing a multi-element, efficient mineralization reaction system. Carbonation is carried out in an atmosphere with controllable humidity and carbon dioxide concentration. Guided by biomimetic acidic template molecules, alkaline earth metal salts and carbon dioxide directionally generate alkaline earth metal carbonate nanosheets (such as Ca2SiO4 and MgO) within the confined channels of biochar. Figure 1 The calcium carbonate nanosheets and magnesium carbonate nanosheets shown give the biochar loaded with alkaline earth metal carbonate nanosheets a biomimetic spheroidal structure, which improves the carbon dioxide capture capacity and carbonation reaction rate of the carbon capture material.

[0078] The directional loading of alkaline earth metal salts guided by biomimetic acidic template molecules, combined with steam-assisted mineralization within the confined channels of the three-dimensional porous network structure of biochar, enables the carbon capture material to exhibit extremely high carbon dioxide capture capacity and rapid mineralization kinetics.

[0079] In some specific embodiments of this application, in an inert atmosphere containing carbon dioxide, the volume content of carbon dioxide can be 1 vol% to 10 vol%. For example, in an inert atmosphere containing carbon dioxide, the volume content of carbon dioxide can be 1 vol%, 2 vol%, 3 vol%, 4 vol%, 5 vol%, 6 vol%, 7 vol%, 8 vol%, 9 vol%, 10 vol%, or any two of the above values, preferably 5 vol%.

[0080] In some specific embodiments of this application, the heat treatment temperature can be 500℃~700℃, and the time can be 1h~3h. For example, the heat treatment temperature can be any two values ​​between 500℃, 520℃, 550℃, 580℃, 600℃, 620℃, 650℃, 680℃, 700℃, or more, preferably 600℃; the heat treatment time can be any two values ​​between 1.0h, 1.2h, 1.5h, 1.8h, 2.0h, 2.2h, 2.5h, 2.8h, 3.0h, or more, preferably 2.0h.

[0081] In some specific embodiments of this application, in an atmosphere containing carbon dioxide and water vapor, the volume content of carbon dioxide can be 2 vol% to 5 vol%. For example, in an atmosphere containing carbon dioxide and water vapor, the volume content of carbon dioxide can be 2 vol%, 2.5 vol%, 3 vol%, 3.5 vol%, 4 vol%, 4.5 vol%, 5 vol%, or any two of the above values, preferably 3 vol%.

[0082] In some specific embodiments of this application, in an atmosphere containing carbon dioxide and water vapor, the partial pressure of water vapor can be 0.5 atm to 0.8 atm. Exemplarily, in an atmosphere containing carbon dioxide and water vapor, the partial pressure of water vapor can be 0.5 atm, 0.55 atm, 0.6 atm, 0.65 atm, 0.7 atm, 0.75 atm, 0.8 atm, or any two of these values, preferably 0.65 atm.

[0083] In some specific embodiments of this application, the carbonation reaction temperature can be 80℃~120℃, and the time can be 6h~24h. Exemplarily, the carbonation reaction temperature can be any two values ​​between 80℃, 90℃, 100℃, 110℃, 120℃, or higher, preferably 100℃; the carbonation reaction time can be any two values ​​between 6h, 8h, 10h, 12h, 15h, 18h, 20h, 22h, 24h, or higher, preferably 12h.

[0084] This application does not particularly limit the equipment used for the aforementioned heat treatment and carbonation reactions, as long as it can achieve the purpose of this application. For example, such as... Figure 1 As shown, the above heat treatment and carbonation reactions can be carried out in a high-temperature reactor.

[0085] It is understandable that, in the case of alkaline earth metal salts including calcium and magnesium salts, although calcium salts and olivine powder are partially converted into alkaline earth metal carbonate nanosheets during the preparation process, the final carbon capture material still contains active components with continuous mineralization capabilities. The incompletely reacted intermediates (MgO, Ca2SiO4, etc.) generated during the heat treatment step exhibit high activity at high fire temperatures, rapidly capturing and mineralizing CO2. Furthermore, the olivine powder is not completely consumed; under the heat flow of the fire, the olivine lattice opens, efficiently reacting with CO2 to form stable magnesium carbonate / magnesium silicate. In addition, the silicon source (TEOS / PDMS) in the composite vesicle membrane undergoes sequential deorganization, densification, and inorganic phase rearrangement under high fire temperatures, capturing CO2 and directly converting it on the material surface to form a carbon-containing ceramic-like inorganic layer, effectively blocking oxygen and heat transfer to the interior. Under the high temperatures of a fire, silicon is the skeletal element that forms a "ceramic-like inorganic layer." It can react with metal oxides to generate a high-temperature resistant silicate ceramic shell, which acts as a physical barrier against heat and oxygen.

[0086] In step S40, such as Figure 1 As shown, biochar loaded with alkaline earth metal carbonate nanosheets is subjected to a third impregnation treatment in a PEI / APP solution and a fourth impregnation treatment in a first TEOS / PDMS sol to allow the alkaline earth metal carbonate nanosheets to self-assemble layer by layer, obtaining a first intermediate. The composite vesicle membrane comprises, from the inside out, a flexible PEI / APP layer and an inorganic / organic mixed TEOS / PDMS layer.

[0087] A layer-by-layer electrostatic self-assembly technique was employed to sequentially coat biochar loaded with alkaline earth metal carbonate nanosheets using PEI / APP solution and a first TEOS / PDMS sol, constructing a biomimetic vesicle structure with a "flexible inner layer (polyethyleneimine / ammonium polyphosphate layer) - rigid outer shell (tetraethyl orthosilicate / polydimethylsiloxane layer)". This structure not only stabilizes the alkaline earth metal carbonate nanosheets but also introduces flame-retardant and hydrophobic properties.

[0088] In some specific embodiments of this application, in step S40, the polyethyleneimine / ammonium polyphosphate solution is a mixed aqueous solution of polyethyleneimine and ammonium polyphosphate. In the polyethyleneimine / ammonium polyphosphate solution, the mass content of polyethyleneimine can be 5wt% to 15wt%, and the mass content of ammonium polyphosphate can be 10wt% to 20wt%. Exemplarily, in the polyethyleneimine / ammonium polyphosphate solution, the mass content of polyethyleneimine can be within the range of any two values ​​of 5wt%, 7wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, or more, preferably 10wt%; the mass content of ammonium polyphosphate can be within the range of any two values ​​of 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, or more, preferably 15wt%.

[0089] The third immersion treatment time can be 30 min to 60 min. For example, the third immersion treatment time can be any two values ​​between 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, and 60 min, preferably 45 min.

[0090] In some specific embodiments of this application, in step S40, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane in the first tetraethyl orthosilicate / polydimethylsiloxane sol can be (1~3):1. Exemplarily, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane in the first tetraethyl orthosilicate / polydimethylsiloxane sol can be 1.0:1, 1.2:1, 1.5:1, 1.8:1, 2.0:1, 2.2:1, 2.5:1, 2.8:1, 3.0:1, or any two of these values, preferably 2.0:1. The pH of the first tetraethyl orthosilicate / polydimethylsiloxane sol can be 10~12. Exemplarily, the pH of the first tetraethyl orthosilicate / polydimethylsiloxane sol can be 10, 10.5, 11, 11.5, 12, or any two of these values, preferably 11. The solvent used for the first tetraethyl orthosilicate / polydimethylsiloxane sol can be ethanol. The first tetraethyl orthosilicate / polydimethylsiloxane sol can be prepared by dissolving tetraethyl orthosilicate and polydimethylsiloxane in ethanol at a mass ratio of (1~3):1 and adjusting the pH to 10~12.

[0091] The fourth immersion treatment time can be 1 hour to 2 hours. For example, the fourth immersion treatment time can be any two of the following values: 1.0 hour, 1.2 hours, 1.5 hours, 1.8 hours, 2.0 hours, or 1.5 hours, preferably 1.5 hours.

[0092] In some specific embodiments of this application, in step S40, after the biochar loaded with alkaline earth metal carbonate nanosheets is subjected to a third impregnation treatment in a polyethyleneimine / ammonium polyphosphate solution and a fourth impregnation treatment in a first tetraethyl orthosilicate / polydimethylsiloxane sol, it can also be initially cured at 60~100°C, preferably at 80°C, to form a coating structure with a primary flexible vesicle membrane and an inorganic / organic mixed shell.

[0093] Inspired by the biomineralization mechanism of natural spheroids, this application breaks through the limitations of traditional biomimetic strategies that only imitate morphology or crystal phase. In a non-living system, through a cascade mechanism of "solid-phase activation (heat treatment) - wet mineralization (carbonation reaction)," it reconstructs the unique vesicle confinement and ordered lamellar nucleation bilayer biological pathway of spheroid mineralization, thus preparing alkaline earth metal carbonate nanosheets. By introducing biomimetic acidic template molecules and interfacial regulation using polyethyleneimine / ammonium polyphosphate layers and tetraethyl orthosilicate / polydimethylsiloxane layers, the alkaline earth metal carbonate nanosheets are induced to spontaneously assemble into hierarchically ordered nanostructures within a closed composite vesicle membrane, successfully coupling flame retardancy, structural reinforcement, and efficient carbon fixation into a single material system.

[0094] In some embodiments of this application, the first intermediate prepared in step S40 above can be used as a carbon capture material, but it is not limited to this. The first intermediate can be further processed to obtain a carbon capture material. For example... Figure 1 As shown, the preparation method of the carbon capture material may further include step S50. In step S50, a hydrophobic composite layer is prepared on the surface of the first intermediate to obtain a second intermediate. The hydrophobic composite layer comprises, from the inside to the outside, a beeswax base layer, a coconut oil intermediate layer, and a tetraethyl orthosilicate / polydimethylsiloxane superhydrophobic coating.

[0095] A humidity gradient and superhydrophobic interface consisting of a beeswax base layer, a coconut oil intermediate layer, and a TEOS / PDMS superhydrophobic coating are constructed on the surface of the composite vesicle membrane. A stable superhydrophobic barrier (contact angle >150°) is built on the surface of the carbon capture material, which can effectively resist external moisture erosion and regulate the internal ion transport of the carbon capture material.

[0096] Therefore, the carbon capture material provided in this application embodiment can integrate CO2 capture, mineralization and storage, flame retardancy and fire resistance, and superhydrophobic protection. The unique composite vesicle membrane and hydrophobic composite layer enable the carbon capture material to adapt to complex environments (such as high temperature, high humidity, and dusty conditions after a wildfire) and achieve controllable humidity management and reaction rate regulation.

[0097] In some specific embodiments of this application, step S50, the method of preparing a hydrophobic composite layer on the surface of the first intermediate includes: sequentially spraying a beeswax acetone dispersion, coconut oil, and a second tetraethyl orthosilicate / polydimethylsiloxane sol onto the surface of the first intermediate.

[0098] In some specific embodiments of this application, the concentration of beeswax in the acetone dispersion can be 1wt% to 5wt%. Exemplarily, the concentration of beeswax in the acetone dispersion can be in the range of any two values ​​between 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, and above, preferably 3wt%.

[0099] In some specific embodiments of this application, the mass ratio of the first intermediate to the beeswax / acetone dispersion can be 1:(0.5~2). Exemplarily, the mass ratio of the first intermediate to the beeswax / acetone dispersion can be 1:0.5, 1:0.8, 1:1.0, 1:1.2, 1:1.5, 1:1.8, 1:2.0 or any two of the above ratios.

[0100] In some specific embodiments of this application, the mass ratio of the first intermediate to coconut oil can be 1:(0.1~0.5). For example, the mass ratio of the first intermediate to coconut oil can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.50 or any two of the above ratios.

[0101] In some specific embodiments of this application, the mass ratio of the first intermediate to the second tetraethyl orthosilicate / polydimethylsiloxane sol can be 1:(1~3). Exemplarily, the mass ratio of the first intermediate to the second tetraethyl orthosilicate / polydimethylsiloxane sol can be 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2.0, 1:2.2, 1:2.5, 1:2.8, 1:3.0, or any two of the above ratios.

[0102] In some specific embodiments of this application, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane in the second tetraethyl orthosilicate / polydimethylsiloxane sol can be (1~3):1. Exemplarily, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane in the second tetraethyl orthosilicate / polydimethylsiloxane sol can be 1.0:1, 1.2:1, 1.5:1, 1.8:1, 2.0:1, 2.2:1, 2.5:1, 2.8:1, 3.0:1, or any two of the above values.

[0103] In some specific embodiments of this application, the solvent used for the second tetraethyl orthosilicate / polydimethylsiloxane sol can be ethanol.

[0104] In some specific embodiments of this application, the pH of the second tetraethyl orthosilicate / polydimethylsiloxane sol can be 10-12. Exemplarily, the pH of the second tetraethyl orthosilicate / polydimethylsiloxane sol can be any two values ​​between 10, 10.5, 11, 11.5, 12, or higher.

[0105] It should be noted that in this application, the first tetraethyl orthosilicate / polydimethylsiloxane sol and the second tetraethyl orthosilicate / polydimethylsiloxane sol may be the same or different.

[0106] In some embodiments of this application, such as Figure 1 As shown, the preparation method of the carbon capture material may further include step S60. In step S60, the second intermediate is subjected to a fifth impregnation treatment in a flame retardant liquid to form a flame retardant layer on the surface of the second intermediate, thereby obtaining a third intermediate. This further improves the flame retardant performance of the carbon capture material.

[0107] In step S60, the concentration of the flame retardant liquid can be 5wt% to 20wt%. For example, the concentration of the flame retardant liquid can be any two values ​​between 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, and above. If the concentration of the flame retardant liquid is too low, a continuous and dense film cannot be formed; if the concentration is too high, problems such as component agglomeration and film cracking may occur. When the concentration of the flame retardant liquid is within the above range, a continuous, dense, and non-porous flame retardant layer can be formed after the fifth impregnation treatment.

[0108] In some specific embodiments of this application, the flame retardant liquid may include at least one of phytic acid and chitosan. When the flame retardant liquid includes phytic acid and chitosan, the molar ratio of phytic acid to chitosan may be 1:(1~2). Exemplarily, when the flame retardant liquid includes phytic acid and chitosan, the molar ratio of phytic acid to chitosan may be 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, or any two of the above values.

[0109] In some specific embodiments of this application, the fifth impregnation treatment time can be 0.5h to 2h, and the temperature can be room temperature, for example, 15℃ to 40℃.

[0110] In some embodiments of this application, such as Figure 1 As shown, the preparation method of the carbon capture material may further include step S70. In step S70, the third intermediate is subjected to hot pressing treatment to obtain the carbon capture material.

[0111] The fifth impregnation and hot-pressing processes enabled the densification and integration of carbon capture materials from nano / micro-scale structures to macroscopic bulk components, significantly improving their overall mechanical strength, flame retardancy, and environmental durability, thus solving the bottleneck of the difficulty in engineering applications of powder materials.

[0112] In some specific embodiments of this application, in step S70, the temperature of the hot pressing treatment can be 80℃~120℃, the pressure can be 3MPa~8MPa, and the time can be 4h~8h. For example, the temperature of the hot pressing treatment can be any two values ​​between 80℃, 90℃, 100℃, 110℃, 120℃, or higher, preferably 100℃; the pressure of the hot pressing treatment can be any two values ​​between 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, or higher, preferably 5MPa; and the time of the hot pressing treatment can be any two values ​​between 4h, 5h, 6h, 7h, 8h, or higher, preferably 6h.

[0113] In summary, the carbon capture material provided in this application integrates multiple functions such as high-capacity carbon dioxide capture and mineralization, excellent structural and thermal stability, active flame retardancy and fire resistance, superhydrophobicity, and environmental adaptability through biomimetic acidic template molecule guidance, multi-level pore confinement, composite vesicle membrane encapsulation, and functionalized surface and interface synergistic design.

[0114] The third aspect of this application provides the application of carbon capture materials in the fields of fire prevention, carbon capture, utilization and storage, especially in the fields of post-wildfire atmospheric carbon removal and mineralization, industrial point source or distributed carbon dioxide capture, and environmental remediation.

[0115] The carbon capture material provided in this application is particularly suitable for extreme or complex environments. It can be directly molded into bulk components or coatings, providing durable physical protection and barrier functions while achieving efficient carbon fixation.

[0116] The present application will now be described in detail with reference to embodiments to facilitate understanding by those skilled in the art. It is important to note that the embodiments are merely illustrative and should not be construed as limiting the scope of protection of the present application. Non-essential improvements and adjustments made to the present application by those skilled in the art based on the above description should still fall within the scope of protection of the present application. Furthermore, any raw materials not described in detail below are commercially available products; any process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art. All raw materials described in this application are obtained commercially, and all materials used in this application are commonly used in the art.

[0117] Example 1

[0118] This embodiment provides a carbon capture material and its preparation method. The preparation method includes steps (1) to (7).

[0119] (1) Pre-dried sugarcane bagasse fiber and long bamboo fiber were mixed at a mass ratio of 2:1. After mechanical combing, the mixture was sheared and mixed at 1000 rpm for 3 minutes to construct a three-dimensional open network with a biomimetic filament exoskeleton. Then, it was pressed and shaped at room temperature and 0.2 MPa pressure to obtain the fiber precursor.

[0120] (2) The fiber precursor was placed in a tube furnace and carbonized at a rate of 5°C / min to 350°C and held at the temperature for 2 hours under a nitrogen atmosphere. Then, the temperature was increased to 700°C at a rate of 10°C / min and held at the temperature for 2 hours for pyrolysis. After natural cooling, high-porosity biochar was obtained.

[0121] (3) The biochar was placed in a 1 mol / L HNO3 / HCl (volume ratio 1:1) mixed acid solution and refluxed at 80°C for 6 hours. After acid washing, it was washed until neutral. Then it was immersed in a 30% H2O2 solution and treated at 50°C for 2 hours for oxidation treatment. Finally, the treated biochar was immersed in a 1.0 wt% short-chain polyaspartic acid aqueous solution for 45 minutes to form an ordered molecular film on the inner wall and surface of the biochar pores by acidic template molecules, thus obtaining templated biochar.

[0122] (4) The templated biochar was impregnated in a 0.5 mol / L Ca(NO3)2 solution for 24 hours, and then dried under vacuum at 110°C for 12 hours. Subsequently, it was mechanically mixed with olivine powder with a particle size of less than 20 μm at a mass ratio of 2:1 to obtain biochar loaded with alkaline earth metal salt.

[0123] (5) The biochar loaded with alkaline earth metal salts was placed in a nitrogen atmosphere containing 5 vol% CO2 and heat-treated at 600°C for 2 hours for gas-solid activation (i.e. heat treatment); then it was transferred to a reactor and carbonated at 100°C in an atmosphere containing 3 vol% CO2 and a water vapor partial pressure of 0.65 atm for 12 hours to generate biochar loaded with alkaline earth metal carbonate nanosheets, which can be used as a composite core.

[0124] (6) The biochar loaded with alkaline earth metal carbonate nanosheets was first immersed in a mixed aqueous solution of 10 wt% polyethyleneimine (PEI) and 15 wt% ammonium polyphosphate (APP) (PEI / APP solution) for 45 minutes. After being taken out, it was gently rinsed with deionized water. Then it was transferred to the first TEOS / PDMS sol prepared by tetraethyl orthosilicate (TEOS) and polydimethylsiloxane (PDMS) at a mass ratio of 2:1 and the pH was adjusted to 11 for 1.5 hours. After that, it was taken out and preliminarily cured at 80°C to form a composite vesicle membrane on the surface of the composite core, thus obtaining the first intermediate.

[0125] (7) First, a 3 wt% beeswax / acetone dispersion is uniformly sprayed onto the surface of the first intermediate to form a hydrophobic substrate; after drying, coconut oil is sprayed on; then, a second TEOS / PDMS sol (the same as the first TEOS / PDMS sol) is sprayed on to obtain the second intermediate, which is tested to have a water contact angle greater than 150°; finally, the second intermediate is immersed in phytic acid flame retardant liquid (10 wt%), and after being taken out, it is hot-pressed at 100°C and 5MPa for 6 hours to form a hydrophobic composite layer and a flame retardant layer on the surface of the first intermediate in sequence, thus obtaining the final carbon capture material.

[0126] Example 2

[0127] This embodiment provides a carbon capture material and its preparation method. The preparation method is the same as in Embodiment 1, except that step (7) is not included in this embodiment; that is, the carbon capture material in this embodiment is a first intermediate. The remaining steps are consistent with those in Embodiment 1.

[0128] Example 3

[0129] This embodiment provides a carbon capture material and its preparation method. The preparation method is the same as in Example 1, except that in step (3) of this embodiment, the biochar is not impregnated in an aqueous solution of short-chain polyaspartic acid. The remaining steps are consistent with those in Example 1.

[0130] Example 4

[0131] This embodiment provides a carbon capture material and its preparation method. The preparation method is the same as in Embodiment 1, except that no heat treatment is performed in step (5) of this embodiment.

[0132] Comparative Example 1

[0133] This embodiment provides a carbon capture material and its preparation method. The preparation method is the same as in Example 1, except that in step (5) of this comparative example, a carbonation reaction is not performed. In this comparative example, because the conditions for triggering the crystal transformation during carbonation were not met, most of the bulk alkaline earth metal carbonates failed to be converted into alkaline earth metal carbonate nanosheets.

[0134] Comparative Example 2

[0135] This comparative example provides a carbon capture material and its preparation method. The preparation method is the same as in Example 1, except that in step (6) of this comparative example, the biochar loaded with alkaline earth metal carbonate nanosheets is not impregnated in the first TEOS / PDMS sol. The remaining steps are consistent with those in Example 1.

[0136] Comparative Example 3

[0137] This comparative example provides a carbon capture material and its preparation method. The preparation method is the same as in Example 1, except that in step (6) of this comparative example, the biochar loaded with alkaline earth metal carbonate nanosheets was not impregnated in PEI / APP solution. The remaining steps are consistent with those in Example 1.

[0138] A comprehensive performance evaluation was conducted on the carbon capture materials provided in Examples 1 to 4 and Comparative Examples 1 to 3.

[0139] The specific surface area and pore size distribution of the material were determined by the BET method under a liquid nitrogen atmosphere at 77K using a fully automated specific surface area and pore size analyzer.

[0140] The static water contact angle of a material surface was measured at room temperature using an optical contact angle meter to evaluate its hydrophobic properties.

[0141] The mechanical strength of the material was tested using a universal testing machine, and its compressive strength was tested at a loading rate of 1 mm / min.

[0142] Regarding flame retardant performance, vertical burning tests were conducted in accordance with UL-94 standard "Test of flammability of plastic materials for equipment and appliance components" to determine the flame retardant rating of the material.

[0143] Carbon capture and mineralization performance tests were conducted using a thermogravimetric analyzer (TGA). Simulated flue gas conditions were set at 100℃, CO2 concentration of 3 vol%, water vapor partial pressure of 0.65 atm, and equilibrium nitrogen. The 12-hour carbonation conversion rate was calculated by recording mass changes in real time. Ten consecutive adsorption-regeneration cycle tests were performed, and the cycle decay rate was calculated by comparing the capture capacity before and after the cycle to evaluate the material's cycle stability.

[0144] The relevant test results are detailed in Table 1.

[0145] Table 1

[0146]

[0147] The carbon capture material provided in this application embodiment can achieve both good cycle stability and high carbonation conversion rate under simulated flue gas conditions.

[0148] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A carbon capture material, characterized in that, The carbon capture material includes: The composite core comprises biochar with a three-dimensional porous network structure and alkaline earth metal carbonate nanosheets arranged in an orderly manner within the three-dimensional porous network structure. A composite vesicle membrane is located on the surface of the composite core, and the composite vesicle membrane comprises, from the inside out, a polyethyleneimine / ammonium polyphosphate layer and an orthosilicate / polydimethylsiloxane layer.

2. The carbon capture material according to claim 1, characterized in that, The biochar is plant fiber biochar; The alkaline earth metal carbonate nanosheets include at least one of calcium carbonate nanosheets and magnesium carbonate nanosheets. The alkaline earth metal carbonate nanosheets are polygonal with a side length of 50nm~500nm and a thickness of 10nm~50nm. In the polyethyleneimine / ammonium polyphosphate layer, the mass ratio of polyethyleneimine to ammonium polyphosphate is (1~3):(2~4). In the tetraethyl orthosilicate / polydimethylsiloxane layer, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane is (1~3):1; The thickness of the composite vesicle membrane is 20nm~100nm; The specific surface area of ​​the carbon capture material is 450 m² / g to 600 m² / g; The pore size of the carbon trapping material is 2nm~50nm.

3. The carbon capture material according to claim 1, characterized in that, The carbon capture material further includes a hydrophobic composite layer located on the surface of the composite vesicle membrane away from the composite core; the hydrophobic composite layer comprises, from the inside out, a beeswax base layer, a coconut oil intermediate layer, and a tetraethyl orthosilicate / polydimethylsiloxane superhydrophobic coating. In the tetraethyl orthosilicate / polydimethylsiloxane superhydrophobic coating, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane is (1~3):1; The carbon capture material further includes a flame-retardant layer located on the surface of the hydrophobic composite layer away from the composite vesicle membrane; the flame-retardant layer includes at least one of phytic acid and chitosan.

4. A method for preparing a carbon capture material according to any one of claims 1 to 3, characterized in that, The preparation method includes: Alkaline earth metal carbonate nanosheets were prepared in the three-dimensional porous network structure of biochar to obtain biochar loaded with alkaline earth metal carbonate nanosheets. The biochar loaded with alkaline earth metal carbonate nanosheets is subjected to a third impregnation treatment in a polyethyleneimine / ammonium polyphosphate solution and a fourth impregnation treatment in a first tetraethyl orthosilicate / polydimethylsiloxane sol to obtain a first intermediate, so as to obtain a carbon capture material.

5. The method for preparing the carbon capture material according to claim 4, characterized in that, The preparation of alkaline earth metal carbonate nanosheets in the three-dimensional porous network structure of biochar to obtain biochar loaded with alkaline earth metal carbonate nanosheets includes: The biochar was first impregnated in a biomimetic acidic template molecule solution to obtain templated biochar. Alkaline earth metal salts are loaded into the three-dimensional porous network structure of the templated biochar to obtain alkaline earth metal salt-loaded biochar. The biochar loaded with alkaline earth metal salts was subjected to carbon dioxide mineralization treatment to obtain biochar loaded with alkaline earth metal carbonate nanosheets.

6. The method for preparing the carbon capture material according to claim 5, characterized in that, The biomimetic acidic template molecule is selected from at least one of short-chain polyaspartic acid and polyglutamic acid; the first impregnation treatment time is 30 min to 60 min, and the temperature is 15℃ to 40℃; the concentration of the biomimetic acidic template molecule solution is 0.5 wt% to 2.0 wt%. The alkaline earth metal salt includes at least one of calcium and magnesium salts; when the alkaline earth metal salt includes calcium and magnesium salts, loading the alkaline earth metal salt into the three-dimensional porous network structure of the templated biochar to obtain alkaline earth metal salt-loaded biochar includes: subjecting the templated biochar to a second impregnation treatment in a calcium salt solution, and drying it to obtain calcium salt-loaded biochar; mixing the calcium salt-loaded biochar with olivine powder to obtain the alkaline earth metal salt-loaded biochar. The concentration of the calcium salt solution is 0.1 mol / L to 1.0 mol / L; the calcium salt solution includes at least one of Ca(NO3)2 and CaCl2; the second impregnation treatment time is 12 h to 36 h, and the temperature is 15 °C to 40 °C; the particle size of the olivine powder is less than 20 μm; the mass ratio of the calcium salt-loaded biochar to the olivine powder is (1 to 3): 1; The carbon dioxide mineralization treatment of the biochar loaded with alkaline earth metal salts includes: heat-treating the biochar loaded with alkaline earth metal salts in an inert atmosphere containing carbon dioxide, and then carrying out a carbonation reaction in an atmosphere containing carbon dioxide and water vapor. In the inert atmosphere containing carbon dioxide, the volume content of carbon dioxide is 1 vol% to 10 vol%; the temperature of the heat treatment is 500℃ to 700℃, and the time is 1 h to 3 h; the temperature of the carbonation reaction is 80℃ to 120℃, and the time is 6 h to 24 h; in the atmosphere containing carbon dioxide and water vapor, the volume content of carbon dioxide is 2 vol% to 5 vol%; in the atmosphere containing carbon dioxide and water vapor, the partial pressure of water vapor is 0.5 atm to 0.8 atm.

7. The method for preparing the carbon capture material according to claim 4, characterized in that, In the polyethyleneimine / ammonium polyphosphate solution, the mass content of polyethyleneimine is 5wt%~15wt%, and the mass content of ammonium polyphosphate is 10wt%~20wt%; the time for the third impregnation treatment is 30min~60min. In the first tetraethyl orthosilicate / polydimethylsiloxane sol, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane is (1~3):1; the pH of the first tetraethyl orthosilicate / polydimethylsiloxane sol is 10~12; and the time of the fourth impregnation treatment is 1h~2h.

8. The method for preparing the carbon capture material according to claim 4, characterized in that, The method for preparing the carbon capture material further includes: before preparing alkaline earth metal carbonate nanosheets in the three-dimensional porous network structure of biochar, the biochar is subjected to acid washing and oxidation treatment in sequence. The pickling process includes: reflux treatment of the biochar in an acidic solution; the concentration of the acidic solution is 0.5~2.0 mol / L; the acidic solution includes at least one of nitric acid and hydrochloric acid; when the acidic solution includes nitric acid and hydrochloric acid, the volume ratio of nitric acid to hydrochloric acid in the acidic solution is (1~2):(1~2); the reflux treatment temperature is 60℃~100℃, and the time is 4h~8h. The oxidation treatment includes placing the acid-washed biochar in a hydrogen peroxide solution for oxidation; the concentration of the hydrogen peroxide solution is 20 vol% to 40 vol%; the oxidation treatment temperature is 40℃ to 60℃, and the time is 1 h to 3 h.

9. The method for preparing the carbon capture material according to claim 4, characterized in that, The method for preparing biochar includes: cutting and mixing plant fibers and pressing them into shape to obtain a fiber precursor; and carbonizing and pyrolyzing the fiber precursor in an inert atmosphere to obtain biochar. The plant fiber includes bagasse fiber and bamboo fiber, and the mass ratio of bagasse fiber to bamboo fiber is (1~3):

1. The shear mixing speed is 800 rpm to 1200 rpm, and the time is 2 min to 5 min; The pressing pressure is 0.1MPa~0.3MPa, and the temperature is 10℃~40℃; The carbonization process involves heating to 300℃~400℃ at a rate of 3℃ / min~8℃ / min and holding at that temperature for 1h~3h. The pyrolysis is performed by heating at a rate of 8℃ / min to 12℃ / min to 650℃ to 750℃ and holding at that temperature for 1h to 3h.

10. The method for preparing the carbon capture material according to any one of claims 4 to 9, characterized in that, The preparation method further includes: A hydrophobic composite layer is prepared on the surface of the first intermediate to obtain a second intermediate. The hydrophobic composite layer comprises, from the inside to the outside, a beeswax base layer, a coconut oil intermediate layer, and a tetraethyl orthosilicate / polydimethylsiloxane superhydrophobic coating. The second intermediate is subjected to a fifth impregnation treatment in a flame retardant liquid to obtain a third intermediate; and... The third intermediate is subjected to hot pressing to obtain a carbon capture material; The method for preparing a hydrophobic composite layer on the surface of the first intermediate includes: sequentially spraying a beeswax acetone dispersion, coconut oil, and a second tetraethyl orthosilicate / polydimethylsiloxane sol onto the surface of the first intermediate. In the acetone dispersion of beeswax, the concentration of beeswax is 1wt%~5wt%; the mass ratio of the first intermediate to the beeswax / acetone dispersion is 1:(0.5~2); the mass ratio of the first intermediate to the coconut oil is 1:(0.1~0.5); the mass ratio of the first intermediate to the second tetraethyl orthosilicate / polydimethylsiloxane sol is 1:(1~3); in the second tetraethyl orthosilicate / polydimethylsiloxane sol, the mass ratio of tetraethyl orthosilicate to polydimethylsiloxane is (1~3):1; the solvent used for the second tetraethyl orthosilicate / polydimethylsiloxane sol is ethanol; the pH of the second tetraethyl orthosilicate / polydimethylsiloxane sol is 10~12. The flame retardant liquid includes at least one of phytic acid and chitosan; the concentration of the flame retardant liquid is 5wt%~20wt%; when the flame retardant liquid includes phytic acid and chitosan, the molar ratio of phytic acid and chitosan is 1:(1~2); the time of the fifth impregnation treatment is 0.5h~2h, and the temperature is 15℃~40℃; The hot pressing treatment is performed at a temperature of 80℃~120℃, a pressure of 3MPa~8MPa, and a time of 4h~8h.

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