Carbon dioxide adsorbent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of adsorption separation, in particular to a carbon dioxide adsorbent and a preparation method and application thereof. The provided carbon dioxide adsorbent comprises an adsorption matrix, the adsorption matrix is provided with a composite pore structure, the composite pore structure comprises mesopores and macropores, the pore diameter range of the mesopores is 10 nm to 50 nm, and the pore diameter range of the macropores is 100 nm to 500 nm; the adsorption matrix comprises at least one of metal oxide or basic salt. The preparation method of the carbon dioxide adsorbent comprises the following steps: mixing an adsorption precursor with a first pore-forming agent, and treating by a chemical method to obtain a first intermediate with mesopores; mixing the first intermediate with a second pore forming agent and a binder to obtain a second intermediate; and carrying out molding treatment and calcination treatment on the second intermediate to obtain the carbon dioxide adsorbent with the composite pore structure. The invention can alleviate the problem that the current carbon dioxide adsorbent is easy to sinter and block after being recycled for many times due to small pore channels.

Description

Technical Field

[0001] The present invention relates to the field of adsorption separation technology, and in particular to carbon dioxide adsorption separation for use in vehicles. Specifically, it relates to a carbon dioxide adsorbent, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, effectively controlling carbon dioxide (CO2) emissions has become a focus of attention across various fields. The development of efficient, low-cost CO2 adsorption materials has also become a hot topic in current research. Among CO2 adsorption materials, calcium-based adsorbents hold great promise for CO2 capture due to their wide availability, low cost, rapid adsorption rates, and high theoretical CO2 adsorption capacity.

[0003] However, the current carbon dioxide adsorption materials still have certain shortcomings. For example, the existing calcium-based adsorbents are prone to sintering, agglomeration, and structural collapse after multiple cycles of high-temperature adsorption and desorption. In order to improve the adsorption performance of the adsorbent, the adsorbent is often required to have a rich pore structure to increase the contact between the adsorbent and the gas. The commonly used pore-making methods currently include chemical activation and the addition of pore-forming agents or templates. However, the existing pore-making technology for adsorption materials only has a single pore-making technology, which mostly has only a mesoporous structure with small pores. After multiple cycles of use, it is still easy to sinter and clog, resulting in a decrease in the adsorption performance and stability of the carbon dioxide adsorbent.

[0004] Therefore, it is of great significance to develop carbon dioxide adsorbents with good adsorption performance and high stability. Summary of the Invention

[0005] In light of this, the present invention aims to address, at least to some extent, one of the technical problems in the related art. To this end, the present invention provides a carbon dioxide adsorbent, its preparation method, and its application. These methods can alleviate the problem of small pores in current carbon dioxide adsorbents, which are prone to sintering and clogging after repeated recycling, thereby improving the adsorption performance and stability of the carbon dioxide adsorbent.

[0006] In order to solve the above technical problems, this application is implemented as follows: According to one aspect of the present application, an embodiment of the present application provides a carbon dioxide adsorbent, the carbon dioxide adsorbent comprising an adsorption matrix having a composite pore structure, the composite pore structure comprising mesopores and macropores, the pore size of the mesopores ranging from 10 nm to 50 nm, and the pore size of the macropores ranging from 100 nm to 500 nm; The adsorption matrix includes at least one of a metal oxide or an alkaline salt.

[0007] In addition, the carbon dioxide adsorbent according to the present application may also have the following additional technical features: In some embodiments, in the composite pore structure, the volume proportion of the mesopores is 25% to 75%.

[0008] In some embodiments, in the composite pore structure, the volume proportion of the macropores is 25% to 75%.

[0009] In some embodiments, the specific surface area of the carbon dioxide adsorbent is 10m 2 / g~50m 2 / g.

[0010] In some embodiments, the average particle size of the carbon dioxide adsorbent is in the range of 3 mm to 9 mm.

[0011] In some embodiments, the pore volume of the carbon dioxide adsorbent is 0.01 cm 3 / g~0.1cm 3 / g.

[0012] In some embodiments, the adsorption matrix includes at least one of a calcium-based adsorbent, a magnesium-based adsorbent, a sodium-based adsorbent, or a potassium-based adsorbent.

[0013] In some embodiments, the carbon dioxide adsorbent further includes a binder, and the binder accounts for 5% to 35% by mass in the carbon dioxide adsorbent, preferably 5% to 33% by mass.

[0014] In some embodiments, the binder includes at least one of cement, bentonite, diatomaceous earth, or sodium silicate.

[0015] According to another aspect of the present application, an embodiment of the present application provides a method for preparing a carbon dioxide adsorbent, the method comprising: The adsorption precursor is mixed with a first pore-forming agent, and treated by a chemical method to obtain a first intermediate having mesopores; mixing the first intermediate with a second pore-forming agent and a binder to obtain a second intermediate; The second intermediate is subjected to molding and calcining treatments to obtain a carbon dioxide adsorbent having a composite pore structure, wherein the composite pore structure includes mesopores and macropores, the pore size of the mesopores ranges from 10 nm to 50 nm, and the pore size of the macropores ranges from 100 nm to 500 nm.

[0016] In some embodiments, the adsorption precursor includes at least one of a calcium precursor, a magnesium precursor, a sodium precursor, or a potassium precursor.

[0017] In some embodiments, the first pore former comprises a soluble organic pore former.

[0018] In some of these embodiments, the second pore former comprises a solid biowaste pore former.

[0019] In some embodiments, the calcium precursor includes at least one of calcium acetate, calcium nitrate, calcium hydroxide, or calcium carbonate.

[0020] In some embodiments, the soluble organic pore former includes at least one of citric acid, ethylene glycol, oxalic acid, or urea.

[0021] In some embodiments, the solid biowaste pore former includes at least one of straw waste, wheat hulls, or maple leaf chips.

[0022] In some embodiments, the average particle size of the solid biological waste pore-forming agent is 1 μm to 1 mm.

[0023] In some embodiments, the step of obtaining a first intermediate having mesopores satisfies at least one of the following characteristics: (1) The chemical method includes at least one of a sol-gel method and an acid impregnation method; (2) mixing the adsorption precursor with the first pore-forming agent comprises: mixing the adsorption precursor, the first pore-forming agent, and the solvent in a molar ratio of 1: (1-3): (30-40); (3) mixing the adsorption precursor with the first pore-forming agent to obtain a mixed solution; Stirring the mixture at 75°C to 85°C for 3h to 6h to obtain a gel; The gel-like substance is allowed to stand at a temperature of 18° C. to 35° C. for 15 to 20 hours, and then dried at a temperature of 75° C. to 85° C. for 2 to 6 hours and at a temperature of 105° C. to 120° C. for 10 to 15 hours to obtain a dried substance; The dried product is calcined at 400° C. to 950° C. and ground to obtain the first intermediate.

[0024] In some embodiments, the preparation method satisfies at least one of the following characteristics: (1) The binder includes at least one of cement, bentonite, diatomaceous earth or sodium silicate; (2) The mass ratio of the first intermediate, the second pore-forming agent and the binder is (18-2):1:1; (3) The molding process includes wet molding, and the wet molding includes: mixing the second intermediate with a solvent to form a mass; Extruding the mass to obtain a strip; cutting the strips into adsorbent particles; drying the adsorbent particles; (4) The calcination temperature is 700°C to 950°C.

[0025] In some embodiments, the wet forming satisfies at least one of the following characteristics: (1) The solvent includes water, and the mass ratio of the second intermediate to water is 1: (20% to 40%); (2) The extrusion process is carried out in a hydraulic extruder, and the parameters of the hydraulic extruder include: The extrusion pressure is 5MPa~20MPa, the extrusion die size is 3mm~9mm, and the extrusion length is 10cm~30cm; (3) The adsorbent particles obtained by cutting include columnar particles with a length of 3 mm to 9 mm and a diameter of 3 mm to 9 mm; (4) The drying temperature is 80°C to 120°C, and the drying time is 2h to 24h; (5) The moisture content of the particles after drying is less than 5%.

[0026] According to another aspect of the present application, an embodiment of the present application provides an application of a carbon dioxide adsorbent, wherein the carbon dioxide adsorbent includes the aforementioned carbon dioxide adsorbent and / or includes the carbon dioxide adsorbent prepared by the aforementioned preparation method; the carbon dioxide adsorbent is used in a vehicle.

[0027] The implementation of the technical solution of the present invention has at least the following beneficial effects: In the present application, the provided carbon dioxide adsorbent includes an adsorption matrix having a composite pore structure, the composite pore structure including mesopores and macropores, and the adsorption matrix includes at least one of a metal oxide or an alkaline salt. Thus, the present invention forms a rich pore structure on the adsorption matrix, which includes both mesopores and macropores, wherein the macropore channels enable the gas to quickly enter the interior of the adsorbent, and the macropore channels are full of rich mesoporous structures, so that the gas can quickly react with the adsorption material, thereby accelerating the reaction rate, allowing the adsorption effective ingredients to fully play their role, and to a certain extent, the adsorption capacity can be improved. During the multiple cycles of use of the carbon dioxide adsorbent, even if some tiny mesopores are blocked due to sintering, the macropore channels can still allow the gas to enter the interior of the adsorbent, thereby alleviating the problem of easy sintering and clogging during multiple cycles, which is conducive to obtaining a higher adsorption capacity, and then helping to improve the adsorption performance and stability of the carbon dioxide adsorbent.

[0028] Additional aspects and advantages of the present application will be given in part in the following description and in part will become obvious from the following description or will be learned through practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Shown is a structural schematic diagram of a carbon dioxide adsorbent provided by an embodiment of the present invention.

[0030] Figure 2 Shown is a schematic flow chart of a method for preparing a carbon dioxide adsorbent provided in an embodiment of the present invention.

[0031] Figure 3 Shown is a comparison diagram of pore size distribution of embodiments and comparative examples provided by the present invention. DETAILED DESCRIPTION

[0032] The present application will be further described below with reference to specific examples. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application.

[0033] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range or the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0034] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0035] The reagents, instruments and materials used in the present invention can be obtained through commercial channels.

[0036] In order to improve the adsorption performance of carbon dioxide adsorbents, adsorbents are often required to have a rich pore structure to increase the contact between the adsorbent and the gas. The commonly used pore-forming methods currently used are chemical activation and the addition of pore-forming agents or templates. In other words, gas adsorbents require a developed pore structure to increase the specific surface area of the adsorbent and ensure that gas molecules can smoothly diffuse into the interior of the adsorbent particles to achieve adsorption and storage. However, there is currently only a single pore-forming technology for pore formation, and most of them only have mesoporous structures with small pores. The adsorbent is still prone to sintering and clogging after multiple cycles of use. In addition, in related technologies, the adsorbent body and the pore-forming agent are mixed by physical methods, and the uniformity of the mixing of the two is greatly affected by the mixing process, which may cause uneven mixing. For example, patent publication number CN117019081A discloses a method for preparing an inorganic adsorbent suitable for fixed-bed CO2 capture, which involves uniformly mixing a powdered calcium oxide or magnesium oxide compound with a pore-forming agent, dripping a high-temperature glue dropwise, drying, crushing into a powder, adding a modifying additive, adding an appropriate binder, molding, primary sintering, boiling in water, and secondary sintering. After cooling, a high-strength, high-porosity inorganic adsorbent suitable for a fixed bed is obtained. However, this method is cumbersome and difficult to operate, making it difficult to achieve large-scale production and ensuring product quality during production. Furthermore, the method remains at the powder stage, with no molding research conducted. For another example, the patent with publication number CN118122286A discloses a solid carbon dioxide adsorbent and a preparation method thereof, first by calcining fly ash and steel slag at high temperature to generate microporous pores, then mixing coke powder, zinc oxide, acrylic acid to carry out finalizing and calcining at high temperature under oxygen isolation to form partial mesopores and more micropores, after a period of time, oxygen is passed through to continue calcining to form more mesopores, and finally a mixture of a surfactant and an organic amine is sprayed on its surface, and the resulting carbon dioxide adsorbent has good adsorption performance. However, this method is applicable to the preparation of calcium-based adsorbents. For another example, the patent with publication number CN118002067A discloses a calcium-based adsorbent and a preparation method thereof, using biomaterials such as straw powder, rice husk powder, pine wood powder as pore-forming agents, after mixed grinding with calcium hydroxide, a binder and forming a mass with water, extrusion granulation is performed to obtain a carbon dioxide adsorbent with good mechanical strength, wear resistance and stable structure. However, this method uses the addition of a single pore-forming agent or pore-forming template, which can only increase mesopores or micropores of a single scale. After the adsorbent is recycled for many times, the smaller mesopores or micropores are still easily blocked by sintering.

[0037] In view of this, in practical applications, existing carbon dioxide adsorbents are prone to sintering and clogging after repeated recycling. Through extensive research, the inventors of this application have provided a carbon dioxide adsorbent, its preparation method, and its application, which can effectively alleviate this problem. A description of the specific technical solution is provided below.

[0038] In some embodiments, the first aspect Figure 1As shown, a carbon dioxide adsorbent is provided, which includes an adsorption matrix having a composite pore structure, the composite pore structure including mesopores and macropores, the pore size range of the mesopores is 10nm to 50nm, and the pore size range of the macropores is 100nm to 500nm; the adsorption matrix includes at least one of a metal oxide or an alkaline salt.

[0039] In the present application, the adsorption matrix may be a metal oxide, or an alkaline salt, or a mixture of a metal oxide and an alkaline salt. The metal oxide may be, for example, calcium oxide, or magnesium oxide, or a mixture of calcium oxide and magnesium oxide. The alkaline salt may be, for example, a sodium-containing alkaline salt, or a potassium-containing alkaline salt, or a mixture of a sodium-containing alkaline salt and an alkali-containing alkaline salt.

[0040] In a preferred embodiment, the adsorption matrix is a metal oxide, such as calcium oxide and / or magnesium oxide. Given that existing calcium-based adsorbents suffer from the problem of small mesopores easily sintering and clogging after repeated use, calcium oxide is a more preferred adsorption matrix in the embodiments of the present invention. In other words, the carbon dioxide adsorbent can be a calcium-based adsorbent, but is not limited thereto. For example, when existing magnesium-based adsorbents have similar problems, magnesium oxide can also be used.

[0041] In the present application, the adsorption matrix has a composite pore structure, which is a composite pore structure with abundant mesopores and macropores. The pore size range of the mesopores is 10nm to 50nm, and the pore size of the macropores is larger than the pore size of the mesopores. Furthermore, in order to avoid the pore size of the macropores being too large and affecting the structural strength of the adsorbent, the pore size of the macropores is 100nm to 500nm. Exemplarily, the pore size of the mesopores can be any point value of 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm or a range value between any two. Exemplarily, the pore size of the macropores can be any point value of 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm or a range value between any two.

[0042] Optionally, the carbon dioxide adsorbent is shaped as one or a combination of geometric shapes such as a sphere, an ellipsoid, a cylinder, a cube, or a cuboid, and this application is not limited thereto. For example, if the carbon dioxide adsorbent is spherical or quasi-spherical, the carbon dioxide adsorbent can be neatly arranged and have a high compaction density.

[0043] In order to overcome the shortcomings of existing carbon dioxide adsorbents, especially calcium-based adsorbents, such as the pore formation of existing calcium-based adsorbents is usually only at a single scale, the embodiment of the present invention combines mesopores with macropores to prepare carbon dioxide adsorbents with composite pore structures, such as calcium-based adsorbents. In a preferred embodiment of the present invention, a more microscopic pore structure is constructed at the adsorbent powder stage by chemical methods, and a larger-scale pore structure is constructed by combining large-particle biological pore-forming agents or biological templates during the molding and granulation process, which is suitable for the application of adsorbents in various scenarios. In the composite pore structure, the mesopores can provide a higher specific surface area and more adsorption sites, but are prone to sintering and clogging during multiple cycles; the macropores are not easy to clog, but the specific surface area will be reduced. The composite pore structure utilizes the structure of the adsorbent itself to alleviate the sintering problem of the adsorbent during multiple cycles, which can reduce the use of anti-sintering agents or make anti-sintering agents unsuitable, increase the proportion of effective ingredients in the adsorbent, and maintain a higher specific surface area, thereby obtaining a higher adsorption capacity. It is also beneficial to improve the adsorption performance and stability of the carbon dioxide adsorbent, and maintain the long-term stability and high adsorption capacity of the carbon dioxide adsorbent.

[0044] In some embodiments, the pore size of the mesopores ranges from 10 nm to 50 nm; preferably, the pore size of the mesopores ranges from 20 nm to 40 nm.

[0045] In some embodiments, the pore size of the macropores ranges from 100 nm to 500 nm; preferably, the pore size of the macropores ranges from 150 nm to 450 nm.

[0046] By controlling the pore size of the mesopores and macropores within the above-mentioned preferred range, the mass transfer performance of the carbon dioxide adsorbent is improved, ensuring the carbon dioxide adsorbent's capacity. This not only avoids sintering and clogging during repeated use, but also maintains a high specific surface area, allowing the gas to react quickly with the adsorbent material. If the pore size of the mesopores and macropores is too large or too small, the capacity and the CO2 flow rate will be affected, resulting in the carbon dioxide adsorbent being unable to effectively adsorb CO2.

[0047] In some embodiments, the volume fraction of mesopores in the composite pore structure is 25% to 75%. For example, the volume fraction of mesopores can be any one of 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, or 75%, or a range therebetween.

[0048] In some embodiments, in the composite pore structure, the volume proportion of the macropores is 25% to 75%. For example, the volume proportion of the macropores can be any one of 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or a range therebetween.

[0049] In some embodiments, the volume ratio of the mesopores to the macropores is 1:3 to 3:1.

[0050] In the composite pore structure of the carbon dioxide adsorbent, controlling the ratio of mesopores to macropores within the above range helps fully utilize the respective functions of the mesopores and macropores. For example, the mesopores can provide a higher specific surface area and more adsorption sites, and the macropores allow gas to quickly enter the adsorbent. This also allows gas to react quickly with the adsorbent material, accelerating the reaction rate, allowing the adsorbed active ingredients to fully exert their effects, and to a certain extent, improving the adsorption capacity. During multiple cycles of use, even if some tiny mesopores become blocked due to sintering, the macropores can still allow gas to enter the adsorbent, ensuring the cyclic stability and adsorption performance of the carbon dioxide adsorbent.

[0051] In some embodiments, the adsorption matrix includes, but is not limited to, at least one of a calcium-based adsorbent, a magnesium-based adsorbent, a sodium-based adsorbent, or a potassium-based adsorbent. The calcium-based adsorbent may include calcium oxide, the magnesium-based adsorbent may include magnesium oxide, the sodium-based adsorbent may include sodium hydroxide or sodium carbonate, and the potassium-based adsorbent may include potassium hydroxide or potassium carbonate.

[0052] Preferably, the adsorption matrix is selected from one or both of calcium oxide and magnesium oxide.

[0053] In some embodiments, the specific surface area of the carbon dioxide adsorbent is 10 m 2 / g~50m 2 / g. For example, the specific surface area of the carbon dioxide adsorbent can be 10m 2 / g, 20m 2 / g、30m 2 / g, 40m 2 / g, 50m 2 Any point value in / g or any range of values between them.

[0054] The carbon dioxide adsorbent of the present application has a high specific surface area, and its specific surface area is 10m 2 / g~50m 2 / g range, thereby improving the adsorption performance of the adsorbent.

[0055] In some embodiments, the average particle size of the carbon dioxide adsorbent ranges from 3 mm to 9 mm. For example, the average particle size of the carbon dioxide adsorbent can be any one of 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, and 9 mm, or a range between any two of them.

[0056] By limiting the particle size of the carbon dioxide adsorbent, its compaction density and other properties can be effectively controlled, thereby effectively controlling the flow rate of CO2 in the adsorbent, ensuring that the carbon dioxide adsorbent can fully contact CO2 and effectively capture CO2. If the particle size of the active particles is too large or too small, the flow rate of CO2 will be affected, resulting in the carbon dioxide adsorbent being unable to effectively adsorb CO2.

[0057] In some embodiments, the pore volume (pore volume) of the carbon dioxide adsorbent is 0.01 cm 3 / g~0.1cm3 / g. For example, the pore volume of the carbon dioxide adsorbent can be 0.01cm 3 / g, 0.02cm 3 / g, 0.03cm 3 / g, 0.05cm 3 / g, 0.08cm 3 / g, 0.1cm 3 Any point value in / g or any range of values between them.

[0058] In the present embodiment, the specific surface area, average particle size, and pore volume of the calcium-based adsorbent are controlled within the aforementioned ranges to enhance the adsorption efficiency of the adsorbent. The carbon dioxide adsorbent within this range has a high specific surface area and rich porosity, which facilitates the construction of abundant active sites, thereby enhancing the adsorption efficiency. This avoids the problem of a reduced specific surface area and restricted pore structure, which reduces the number of active sites in the adsorbent and hinders the improvement of carbon dioxide adsorption.

[0059] It should be noted that this application does not limit the testing methods for the particle size, specific surface area, pore volume (pore volume), mesopore diameter, or macropore diameter of the carbon dioxide adsorbent. Conventional methods in the art can be used to measure these parameters. For example, the pore volume and specific surface area of the carbon dioxide adsorbent can be calculated using low-temperature nitrogen adsorption-desorption isotherms combined with BET and BJH theory. Furthermore, the macropore diameter can be measured using the pressure-gold method, which calculates the pore size based on the relationship between pressure and mercury volume. The carbon dioxide adsorption capacity is calculated using thermogravimetric analysis (TGA) experiments. Methods for measuring the particle size of the carbon dioxide adsorbent include, but are not limited to, laser particle size analysis, microscopy (such as SEM or TEM), or electrical resistance analysis. Preferably, the particle size of the carbon dioxide adsorbent is measured using a particle strength tester.

[0060] In some embodiments, the carbon dioxide adsorbent further comprises a binder, and the binder accounts for 5% to 35% by weight of the carbon dioxide adsorbent, preferably 5% to 33% by weight. For example, the binder accounts for any of 5%, 6%, 8%, 10%, 15%, 20%, 25%, 30%, 33%, and 35% by weight of the carbon dioxide adsorbent, or a range therebetween.

[0061] Optionally, the binder includes at least one of cement, bentonite, diatomaceous earth or sodium silicate.

[0062] In carbon dioxide adsorbents, the roles that binders can play are as follows: on the one hand, binders can enable the final granular material to maintain a certain particle strength / compressive strength and improve its durability; on the other hand, during the wet molding process, binders can help the powder to bond to form agglomerates, improve the plasticity of the agglomerates, and improve the uniformity of material dispersion after sufficient stirring and kneading.

[0063] In a second aspect, in some embodiments, a method for preparing the carbon dioxide adsorbent according to the first aspect is provided, the method comprising: The adsorption precursor is mixed with a first pore-forming agent, and treated by a chemical method to obtain a first intermediate having mesopores; mixing the first intermediate with a second pore-forming agent and a binder to obtain a second intermediate; The second intermediate is subjected to molding and calcining treatments to obtain a carbon dioxide adsorbent with a composite pore structure, wherein the composite pore structure includes mesopores and macropores, the pore diameter of the mesopores ranges from 10nm to 50nm, and the pore diameter of the macropores ranges from 100nm to 500nm.

[0064] The preparation method of the present invention combines multiple pore-forming methods, using chemical methods (sol-gel method, acid impregnation, etc.) to form a rich mesoporous structure. Subsequently, by adding a second pore-forming agent with larger particles, such as waste biomass (straw waste, wheat hulls, maple leaf fragments, etc.), a macroporous channel structure is formed after calcination. These macroporous channels allow gas to quickly enter the adsorbent. The rich mesoporous structure of these macroporous channels allows gas to react quickly with the adsorbent, accelerating the reaction rate and allowing the active ingredients to fully function, thereby increasing adsorption capacity to a certain extent. This allows gas to enter the adsorbent even after repeated cycles of use, even if some tiny mesopores become blocked due to sintering. In a preferred embodiment, the use of waste biomass as the macroporous pore-forming agent (secondary pore-forming agent) achieves waste recycling, improves resource utilization, and reduces costs.

[0065] In the preparation method of the present invention, mechanical mixing is introduced to uniformly mix the adsorbent and the waste biological pore-forming agent, and a more uniform pore structure is formed after calcination.

[0066] The carbon dioxide adsorbent prepared by the preparation method of the present invention has a composite pore structure that utilizes the structure of the adsorbent itself to alleviate the sintering problem of the adsorbent during multiple cycles of use, which can reduce the use of anti-sintering agents or make anti-sintering agents unnecessary, increase the proportion of effective ingredients in the adsorbent, and maintain a high specific surface area, thereby obtaining a higher adsorption capacity.

[0067] The preparation methods provided by the present invention are all relatively mature methods in adsorbent production, are conducive to scaled production and practical use, and are easy to achieve large-scale production.

[0068] It should be understood that the “method for preparing a carbon dioxide adsorbent” and the aforementioned “carbon dioxide adsorbent” are based on the same inventive concept, and all the features and advantages described above for the “carbon dioxide adsorbent” are also applicable to the “method for preparing a carbon dioxide adsorbent” and will not be repeated here.

[0069] In some specific embodiments, such as Figure 2 As shown, the method for preparing the carbon dioxide adsorbent includes the following steps S100 to S400: Step S100: preparing a first intermediate.

[0070] In step S100 , an adsorption precursor is mixed with a first pore-forming agent, and treated by a chemical method to obtain a first intermediate having mesopores.

[0071] Optionally, in step S100, the adsorption precursor includes but is not limited to at least one of a calcium precursor, a magnesium precursor, a sodium precursor or a potassium precursor.

[0072] Preferably, the adsorption precursor is selected from a calcium precursor and / or a magnesium precursor. More preferably, the adsorption precursor is selected from a calcium precursor.

[0073] In some specific embodiments, the calcium precursor includes, but is not limited to, any one of calcium acetate, calcium nitrate, calcium hydroxide, or calcium carbonate, or a combination of at least two thereof.

[0074] Optionally, in step S100, the first pore-forming agent includes a soluble organic pore-forming agent.

[0075] In some specific embodiments, the soluble organic pore-forming agent includes, but is not limited to, any one of citric acid, ethylene glycol, oxalic acid, or urea, or a combination of at least two thereof.

[0076] By selecting the above-mentioned soluble organic pore-forming agents, not only are they widely available and easy to obtain, but the decomposition temperature of these pore-forming agents meets the requirements of use, and they can be mixed with adsorption precursors to form intermediates with microscopic pore structures (such as mesopores). The operation is simple and easy to control.

[0077] Optionally, in step S100, the chemical method includes but is not limited to at least one of a sol-gel method and an acid impregnation method. For example, the mesopore formation can be performed using a sol-gel method, or the mesopore formation can be performed using an acid impregnation method.

[0078] Optionally, in step S100, mixing the adsorption precursor with the first pore-forming agent includes mixing the adsorption precursor, the first pore-forming agent, and a solvent in a molar ratio of 1:(1-3):(30-40) to obtain a mixed solution. The solvent may be water, such as deionized water. For example, the molar ratio of the adsorption precursor, the first pore-forming agent, and the solvent may be 1:1:30, 1:1:35, 1:1:40, 1:2:30, 1:2:40, 1:3:30, 1:3:40, and the like.

[0079] After obtaining the mixed solution, the mixed solution is stirred at 75° C. to 85° C. for 3 to 6 hours to obtain a gel. For example, the stirring temperature may be any one of 75° C., 78° C., 80° C., 82° C., and 85° C., or a range therebetween; and the stirring time may be any one of 3 hours, 4 hours, 5 hours, and 6 hours, or a range therebetween.

[0080] Further, after obtaining the gel, the gel is allowed to stand at a temperature of 18°C to 35°C (preferably 18°C to 31°C) for 15 to 20 hours, and then dried at a temperature of 75°C to 85°C for 2 to 6 hours and at a temperature of 105°C to 120°C for 10 to 15 hours to obtain a dried product; Furthermore, after obtaining the dried product, the dried product is calcined at 400°C to 950°C (or 400°C to 900°C) and ground to obtain a first intermediate; the calcination temperature is preferably 600°C to 900°C. Optionally, the calcination atmosphere can be air. As an example, the calcination temperature can be any one of 400°C, 500°C, 600°C, 700°C, 800°C, 900°C, and 950°C, or a range between any two of them; For example, in some specific implementations, step S100 specifically includes: An adsorption precursor, a first pore-forming agent (such as a soluble organic pore-forming agent) and a solvent (such as water) are mixed in a molar ratio of 1: (1-3): (30-40) to obtain a mixed solution; the mixed solution is stirred at 75°C to 85°C for 3h to 6h until a gel is formed; the gel is allowed to stand at a temperature of 18°C to 31°C for 15h to 20h, and then dried at a temperature of 75°C to 85°C for 2h to 6h and at a temperature of 105°C to 120°C for 10h to 15h to obtain a dried product; the dried product is calcined in an air atmosphere at 400°C to 900°C and ground to obtain a first intermediate.

[0081] Step S200: preparing a second intermediate.

[0082] In step S200 , the first intermediate is mixed with a second pore-forming agent and a binder to obtain a second intermediate.

[0083] Optionally, in step S200, the second pore-forming agent includes a solid biological waste pore-forming agent.

[0084] In some specific embodiments, the solid biowaste pore former includes, but is not limited to, any one of straw waste, wheat husks, or maple leaf chips, or a combination of at least two thereof.

[0085] By selecting the aforementioned solid biowaste pore-forming agents, which are waste plant materials, these waste plant materials can naturally burn or decompose during the calcination process, thereby forming macropores in the adsorbent particles. By using waste biowaste as a macroporous structure pore-forming agent, the present invention achieves waste utilization, improves resource utilization, reduces costs, and is safe and environmentally friendly.

[0086] In some specific embodiments, the average particle size of the solid biological waste pore-forming agent is 1 μm to 1 mm. For example, the average particle size of the solid biological waste pore-forming agent can be any one of 1 μm, 10 μm, 50 μm, 100 μm, 500 μm, 600 μm, 800 μm, and 1 mm, or a range between any two of them.

[0087] Optionally, in step S200, the binder includes, but is not limited to, any one of cement, bentonite, diatomaceous earth or sodium silicate, or a combination of at least two of them.

[0088] It should be noted that the present application does not limit the specific models or sources of the above-mentioned adhesives, which can be purchased from the market or can also be made by ourselves.

[0089] By adding the above-mentioned binders during the preparation of the second intermediate, on the one hand, the final granular material can maintain a certain particle strength / compressive strength and improve its durability; on the other hand, during the wet molding process, the binder can help the powder to bond to form agglomerates, improve the plasticity of the agglomerates, and improve the uniformity of material dispersion after sufficient stirring and kneading.

[0090] Optionally, in step S200, the mass ratio of the first intermediate, the second pore-forming agent, and the binder is (18-2):1:1. For example, the mass ratio of the first intermediate, the second pore-forming agent, and the binder can be any one of 2:1:1, 4:1:1, 5:1:1, 6:1:1, 8:1:1, 10:1:1, 12:1:1, 15:1:1, and 18:1:1, or a range between any two of the above.

[0091] By controlling the mass ratio of the first intermediate, the second pore-forming agent, and the binder within the above range, a reasonable distribution of the mesoporous and macroporous composite pore structure can be ensured, resulting in the product particles having high adsorption performance while maintaining a certain particle strength. If the mass ratio of the first intermediate is too large, the pore-forming agent and binder content will be insufficient to function, and the final adsorbent product will have no macroporous structure or too few macropores to improve gas permeability, and the particle strength will be low. If the mass ratio of the first intermediate is too small, the effective adsorption components will be greatly reduced, the mesopore distribution will be reduced, and the adsorption capacity of the final product will not meet the application requirements.

[0092] Therefore, in step S200, the second intermediate can be obtained by mixing the first intermediate with a second pore-forming agent with a larger particle size, such as a solid waste biological pore-forming agent with a larger particle size, and a binder in proportion.

[0093] Step S300: forming process.

[0094] In step S300, the second intermediate is subjected to a molding process, for example, wet molding is selected to process the second intermediate into particles of a desired shape.

[0095] Optionally, in step S300, the molding process includes wet molding, which specifically includes: Mixing the second intermediate with a solvent to form a mass; wherein the solvent may be water, such as deionized water; The mass is extruded to obtain a strip; cutting the strips into adsorbent particles; The adsorbent particles are dried.

[0096] Optionally, the mass ratio of the second intermediate to water is 1:(20% to 40%); for example, it can be 1:20%, 1:25%, 1:30%, 1:35%, 1:40%, etc.

[0097] Optionally, the extrusion process may be performed by placing the dough into a hydraulic extruder for extrusion, wherein the parameters of the hydraulic extruder include: an extrusion pressure of 5 MPa to 20 MPa, an extrusion die size of 3 mm to 9 mm, and an extrusion length of 10 cm to 30 cm.

[0098] Optionally, the adsorbent particles obtained by cutting include columnar particles with a length of 3 mm to 9 mm and a diameter of 3 mm to 9 mm.

[0099] Optionally, the drying temperature is 80°C to 120°C, and the drying time is 2h to 24h; Optionally, the moisture content of the granules after drying is less than 5%.

[0100] For example, in some specific implementations, step S300 specifically includes: 20% to 40% deionized water is added to the second intermediate, and the mixture is mixed and kneaded in a kneading agent to form a mass; the mass is then placed in a hydraulic extruder to prepare a strip; wherein the parameters of the hydraulic extruder include: an extrusion pressure of 5MPa to 20MPa, an extrusion die size of 3mm to 9mm, and an extrusion length of 10cm to 30cm; then, the extruded strip material is cut into adsorbent particles of the same size; the adsorbent particles after cutting are columnar particles with a length of 3mm to 9mm and a diameter of 3mm to 9mm, and the cutting should ensure that the cut is smooth and the particles are not deformed; then, the cut adsorbent particles are placed in an oven for drying at a drying temperature of 80°C to 120°C and a drying time of 2h to 24h; the moisture content of the particles after drying should be less than 5%.

[0101] Step S400: calcination treatment.

[0102] In step S400, the formed particles are calcined to finally obtain a carbon dioxide adsorbent particle material having a composite pore structure of mesopores and macropores.

[0103] Optionally, in step S400, the calcination temperature is 700°C to 950°C, for example, it can be any one of 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, or a range between any two of them.

[0104] By controlling the calcination temperature within the above range, it is possible to ensure that the formed particles fully react to generate active ingredients with higher purity, thereby ensuring the performance of subsequent products.

[0105] Thus, based on the above settings, the inventors of the present application creatively proposed a carbon dioxide adsorbent and a preparation method thereof, which combines mesopores with macropores to prepare a carbon dioxide adsorbent with a composite pore structure. A more microscopic pore structure is constructed at the adsorbent powder stage by chemical methods, and a larger-scale pore structure is constructed by combining large-particle biological pore-forming agents or biological templates in the molding and granulation process, which is suitable for the application of adsorbents in various scenarios. Mesopores can provide a higher specific surface area and more adsorption sites, but are prone to sintering and clogging during multiple cycles of use; macropores are not easy to clog, but the specific surface area will be reduced. The composite pore structure utilizes the structure of the adsorbent itself to alleviate the sintering problem of the adsorbent during multiple cycles of use, which can reduce the use of anti-sintering agents or make anti-sintering agents unsuitable, increase the proportion of effective ingredients in the adsorbent, and maintain a higher specific surface area, thereby obtaining a higher adsorption capacity.

[0106] In a third aspect, in some embodiments, an application of a carbon dioxide adsorbent is provided, the carbon dioxide adsorbent including the aforementioned carbon dioxide adsorbent, and / or, including the carbon dioxide adsorbent prepared by the aforementioned preparation method; the carbon dioxide adsorbent is used in a vehicle.

[0107] The carbon dioxide adsorbent of the present application can be used in vehicles, such as in the field of vehicle exhaust gas treatment. Adsorbing carbon dioxide in vehicle exhaust can not only reduce carbon emissions and protect the ecological environment; it can also reuse the adsorbed carbon dioxide to produce methanol. For example, the vehicle has a carbon bin, and the carbon dioxide adsorbent can be set in the carbon bin, such as placing the carbon dioxide adsorbent in the reaction chamber of the vehicle carbon bin, and the reaction chamber has an air inlet and an air outlet. When the vehicle exhaust enters from the air inlet, it can react with the carbon dioxide adsorbent in the reaction chamber, and the reaction product gas is discharged from the air outlet.

[0108] It should be understood that the carbon dioxide adsorbent can be used in the field of vehicle exhaust gas treatment, but is not limited to this. The carbon dioxide adsorbent can also be used in other scenarios with similar requirements.

[0109] In order to better understand the present invention, the specific implementation process of the present invention will be described in detail below in a specific implementation mode. The embodiments described below are exemplary and are only used to explain this application and are not to be construed as limiting this application. If specific techniques or conditions are not specified in the embodiments, they shall be carried out in accordance with the techniques or conditions described in the literature in this field or in accordance with the product specifications.

[0110] Example 1 The preparation of the carbon dioxide adsorbent comprises the following steps: S100. Mix the adsorption precursor calcium hydroxide, the soluble organic pore-forming agent citric acid and the solvent water in a molar ratio of 1:1:35 to obtain a mixed solution; stir the mixed solution at 80°C for 4 hours until a gel is formed; let the gel stand at 25°C for 18 hours, and then dry it at 80°C for 3 hours and at 110°C for 12 hours to obtain a dried product; calcinate the dried product at 850°C in an air atmosphere and grind it to obtain a first intermediate.

[0111] S200, mixing the first intermediate, solid waste bioporation agent straw waste, and binder cement in a mass ratio of 90:5:5 to obtain a second intermediate.

[0112] S300. Add 30% deionized water to the above-mentioned second intermediate and knead it into a mass; then place the mass in a hydraulic extruder to prepare it into a strip; wherein the parameters of the hydraulic extruder include: extrusion pressure of 15 MPa, extrusion die size of 5 mm, and extrusion length of 20 cm; then, cut the extruded strip material into adsorbent particles of the same size; the adsorbent particles after cutting are columnar particles with a length of 5 mm and a diameter of 5 mm; then, place the cut adsorbent particles in an oven for drying at a drying temperature of 100°C and a drying time of 10 hours; the moisture content of the particles after drying is less than 5%.

[0113] S400, calcining the formed particles at a temperature of 800° C., and finally obtaining a carbon dioxide adsorbent particle material having a composite pore structure of mesopores and macropores.

[0114] Example 2 The difference between Example 2 and Example 1 is that: In step S100 , the adsorption precursor calcium acetate, the soluble organic pore-forming agent citric acid, and the solvent water are mixed in a molar ratio of 1:2:35.

[0115] The rest are the same as in Example 1.

[0116] Example 3 The difference between Example 3 and Example 1 is that: In step S100, the adsorption precursor calcium acetate, the soluble organic pore-forming agent citric acid and the solvent water are mixed in a molar ratio of 1:1:35; In step S200, the first intermediate, the solid waste biological pore-forming agent straw waste, and the binder bentonite are mixed in a mass ratio of 80:10:10 to obtain a second intermediate.

[0117] The rest are the same as in Example 1.

[0118] Example 4 The difference between Example 4 and Example 1 is that: In step S100, the adsorption precursor calcium hydroxide, the soluble organic pore-forming agent ethylene glycol and the solvent water are mixed in a molar ratio of 1:1:35; In step S200, the first intermediate, the solid waste biological pore-forming agent wheat hulls, and the binder cement are mixed in a mass ratio of 90:5:5 to obtain a second intermediate.

[0119] The rest are the same as in Example 1.

[0120] Example 5 The difference between Example 5 and Example 1 is that: In step S300, 40% deionized water is added to the second intermediate and kneaded into a mass; the mass is then placed in a hydraulic extruder to prepare a strip; wherein the parameters of the hydraulic extruder include: an extrusion pressure of 10 MPa, an extrusion die size of 3 mm, and an extrusion length of 10 cm; then, the extruded strip material is cut into adsorbent particles of the same size; the adsorbent particles after cutting are columnar particles with a length of 3 mm and a diameter of 3 mm; then, the cut adsorbent particles are placed in an oven for drying at a drying temperature of 105°C for 8 hours; the moisture content of the particles after drying is less than 5%.

[0121] The rest are the same as in Example 1.

[0122] Example 6 The difference between Example 6 and Example 1 is that: In step S300, 40% deionized water is added to the second intermediate and kneaded into a mass; the mass is then placed in a hydraulic extruder to prepare a strip; wherein the parameters of the hydraulic extruder include: an extrusion pressure of 20 MPa, an extrusion die size of 9 mm, and an extrusion length of 30 cm; then, the extruded strip material is cut into adsorbent particles of the same size; the adsorbent particles after cutting are columnar particles with a length of 9 mm and a diameter of 9 mm; then, the cut adsorbent particles are placed in an oven for drying at a drying temperature of 120°C for a drying time of 4 hours; the moisture content of the particles after drying is less than 5%.

[0123] The rest are the same as in Example 1.

[0124] Example 7 The difference between Example 7 and Example 1 is that: In step S400, the calcination temperature is 700°C; The rest are the same as in Example 1.

[0125] Example 8 The difference between Example 8 and Example 1 is that: In step S400 , the calcination temperature is 950° C.

[0126] The rest are the same as in Example 1.

[0127] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that: In this comparative example, the addition of a solid waste bioporogen and a binder was omitted during the preparation of the carbon dioxide adsorbent. All other steps and conditions remained unchanged. That is, in Comparative Example 1, no solid waste bioporogen was added, resulting in no macropore formation.

[0128] In Comparative Example 1, there is only a mesoporous structure and no macropore-forming process. Compared with Example 1, it aims to highlight the macropore-forming effect of the larger particle size solid waste bioporogen and the effect of the binder on improving the particle strength.

[0129] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that: In this comparative example, the addition of citric acid, a soluble organic pore-forming agent, and the use of the sol-gel method were omitted in the preparation of the carbon dioxide adsorbent. The remaining steps and conditions were the same as those in Example 1. That is, Comparative Example 2 did not involve mesopore formation.

[0130] Compared with Example 1, Comparative Example 2 has no mesoporous structure but only a macroporous structure, which highlights the influence of the sol-gel method and the soluble organic pore-forming agent on the pore structure and adsorption performance of the final product.

[0131] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that: In the preparation of the carbon dioxide adsorbent in this comparative example, the mesopore formation and macropore formation steps were omitted, and water was directly added to form granules under the same conditions as in Example 1. Comparative Example 3 had neither mesopore formation nor macropore formation.

[0132] The comparison with Example 1 is intended to highlight the influence of the mesoporous and macroporous composite structure on the pore structure and adsorption performance of the final product.

[0133] Performance Testing The carbon dioxide adsorbents obtained in the above examples and comparative examples were subjected to performance tests, including: (1) Particle strength test: Use a particle strength meter to complete the particle strength test.

[0134] (2) Adsorption capacity test: The prepared particle sample was ground into powder using a mortar and pestle, and the adsorption capacity test of the adsorbent was completed using TGA. The experimental gas was 15 vol.% CO2, N2 was the balance gas, the reaction temperature was 25°C to 800°C, and the heating rate was 10°C / min. The maximum weight gain ratio of the sample was recorded to calculate the adsorption capacity.

[0135] The test results are shown in Table 1 below.

[0136] Table 1 Preparation parameters and test results of carbon dioxide adsorbents in various examples and comparative examples As can be seen from Table 1, the carbon dioxide adsorbents prepared in Examples 1 to 8 of the present invention meet the design standards, forming carbon dioxide adsorbents with a composite pore structure of mesopores and macropores, and the particle strength and adsorption capacity both meet the design requirements.

[0137] The sample of Comparative Example 1 did not use the sol-gel method for mesopore formation, and the remaining steps were the same as the examples. No rich mesoporous structure was formed. Although the particle strength met the requirements, the adsorption capacity decreased compared to the examples. This shows that the rich mesoporous structure has a significant effect on improving adsorption performance. Comparative Example 2 did not add a macroporous pore-forming agent. Although mesopore formation was performed, the mesoporous structure was easily clogged during use due to the lack of a macroporous pore-forming agent. Therefore, the adsorption capacity was not significantly improved. Although the particles have a higher strength due to the presence of the binder, the adsorption capacity cannot meet the use requirements. Comparative Example 3 only uses the mesoporous pore-forming step without other additives. Although the adsorption capacity is higher, the particle strength is too low and does not meet the use requirements.

[0138] also, Figure 3 A comparison of the pore size distributions of some examples and comparative examples is shown. Peaks are found in both mesopores (10-50 nm) and macropores (100-300 nm), indicating that Example 1 exhibits both mesopore and macropore distributions. In contrast, single mesopore or single macropore pore creation exhibits a single peak within its pore size range, as shown in Comparative Examples 1 and 2, respectively. Comparative Example 3 did not undergo pore creation. This demonstrates that the synergistic effect of composite pore sizes can enhance adsorbent performance.

[0139] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0140] The basic principles of the present invention have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in the present invention are merely illustrative and non-limiting, and should not be construed as necessarily possessed by each embodiment of the present invention. Furthermore, the specific details disclosed above are provided for illustrative purposes and to facilitate understanding, and are not intended to be limiting. These details do not necessarily limit the present invention to being implemented using these specific details.

[0141] It should be noted that the terms "and / or" or " / " used herein are merely a description of an association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone. The singular forms "a," "the," and "the" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0142] In the detailed description and claims, a list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A carbon dioxide adsorbent, characterized in that The carbon dioxide adsorbent includes an adsorption matrix having a composite pore structure, the composite pore structure including mesopores and macropores, the pore size of the mesopores ranges from 10 nm to 50 nm, and the pore size of the macropores ranges from 100 nm to 500 nm; The adsorption matrix includes at least one of a metal oxide or an alkaline salt.

2. The carbon dioxide adsorbent according to claim 1, characterized in that In the composite pore structure, the volume proportion of the mesopores is 25% to 75%; And / or, in the composite pore structure, the volume proportion of the macropores is 25% to 75%.

3. The carbon dioxide adsorbent according to claim 1 or 2, characterized in that The specific surface area of the carbon dioxide adsorbent is 10m 2 / g~50m 2 / g; and / or, the average particle size of the carbon dioxide adsorbent is in the range of 3 mm to 9 mm; And / or, the pore volume of the carbon dioxide adsorbent is 0.01 cm 3 / g~0.1cm 3 / g; and / or, the adsorption matrix comprises at least one of a calcium-based adsorbent, a magnesium-based adsorbent, a sodium-based adsorbent, or a potassium-based adsorbent; And / or, the carbon dioxide adsorbent further includes a binder, and the binder accounts for 5% to 35% by mass of the carbon dioxide adsorbent.

4. A method for preparing a carbon dioxide adsorbent, characterized in that: The method comprises: The adsorption precursor is mixed with a first pore-forming agent, and treated by a chemical method to obtain a first intermediate having mesopores; mixing the first intermediate with a second pore-forming agent and a binder to obtain a second intermediate; The second intermediate is subjected to molding and calcining treatments to obtain a carbon dioxide adsorbent having a composite pore structure, wherein the composite pore structure includes mesopores and macropores, the pore size of the mesopores ranges from 10 nm to 50 nm, and the pore size of the macropores ranges from 100 nm to 500 nm.

5. The method for preparing a carbon dioxide adsorbent according to claim 4, characterized in that: The adsorption precursor includes at least one of a calcium precursor, a magnesium precursor, a sodium precursor, or a potassium precursor; and / or, the first pore-forming agent comprises a soluble organic pore-forming agent; And / or, the second pore-forming agent comprises a solid biological waste pore-forming agent.

6. The method for preparing a carbon dioxide adsorbent according to claim 5, wherein: The calcium precursor includes at least one of calcium acetate, calcium nitrate, calcium hydroxide or calcium carbonate; and / or, the soluble organic pore-forming agent comprises at least one of citric acid, ethylene glycol, oxalic acid or urea; and / or, the solid biowaste pore-forming agent comprises at least one of straw waste, wheat husks, or maple leaf fragments; And / or, the average particle size of the solid biological waste pore-forming agent is 1 μm to 1 mm.

7. The method for preparing a carbon dioxide adsorbent according to claim 4, wherein: The step of obtaining the first intermediate having mesopores satisfies at least one of the following characteristics: (1) The chemical method includes at least one of a sol-gel method and an acid impregnation method; (2) mixing the adsorption precursor with the first pore-forming agent comprises: mixing the adsorption precursor, the first pore-forming agent, and the solvent in a molar ratio of 1: (1-3): (30-40); (3) mixing the adsorption precursor with the first pore-forming agent to obtain a mixed solution; Stirring the mixture at 75°C to 85°C for 3h to 6h to obtain a gel; The gel-like substance is allowed to stand at a temperature of 18° C. to 35° C. for 15 to 20 hours, and then dried at a temperature of 75° C. to 85° C. for 2 to 6 hours and at a temperature of 105° C. to 120° C. for 10 to 15 hours to obtain a dried substance; The dried product is calcined at 400° C. to 950° C. and ground to obtain the first intermediate.

8. The method for preparing a carbon dioxide adsorbent according to any one of claims 4 to 7, characterized in that: The preparation method satisfies at least one of the following characteristics: (1) The binder includes at least one of cement, bentonite, diatomaceous earth or sodium silicate; (2) The mass ratio of the first intermediate, the second pore-forming agent and the binder is (18-2):1:1; (3) The molding process includes wet molding, and the wet molding includes: mixing the second intermediate with a solvent to form a mass; Extruding the mass to obtain a strip; cutting the strips into adsorbent particles; drying the adsorbent particles; (4) The calcination temperature is 700°C to 950°C.

9. The method for preparing a carbon dioxide adsorbent according to claim 8, wherein: The wet forming satisfies at least one of the following characteristics: (1) The solvent includes water, and the mass ratio of the second intermediate to water is 1: (20% to 40%); (2) The extrusion process is carried out in a hydraulic extruder, and the parameters of the hydraulic extruder include: The extrusion pressure is 5MPa~20MPa, the extrusion die size is 3mm~9mm, and the extrusion length is 10cm~30cm; (3) The adsorbent particles obtained by cutting include columnar particles with a length of 3 mm to 9 mm and a diameter of 3 mm to 9 mm; (4) The drying temperature is 80°C to 120°C, and the drying time is 2h to 24h; (5) The moisture content of the particles after drying is less than 5%.

10. An application of a carbon dioxide adsorbent, characterized in that: The carbon dioxide adsorbent includes the carbon dioxide adsorbent according to any one of claims 1 to 3, and / or includes the carbon dioxide adsorbent prepared by the preparation method according to any one of claims 4 to 9; The carbon dioxide absorbent is used in a vehicle.

Images