High-efficiency solid atmospheric carbon capture material, preparation method and application thereof

Abstract

The application provides a preparation method of high-efficiency solid air carbon capture material, comprising the following steps: firstly, adding a titanate crosslinking agent into an organic solvent to obtain an impregnation solution; secondly, adding a zirconium dioxide carrier into the impregnation solution for sufficient impregnation, and then drying, calcining and grinding to obtain a first product; finally, adding the first product into an aqueous potassium carbonate solution for sufficient impregnation, and then drying, calcining, grinding and screening to obtain the high-efficiency solid air carbon capture material. The high-efficiency solid air carbon capture material prepared by the application has the advantages of structural stability, uniform component dispersion, large adsorption capacity, strong carbon dioxide selectivity and good cycle stability, and can be used for directly capturing carbon dioxide in air, thereby reducing the adsorption temperature and desorption temperature of the potassium-based adsorbent and meeting the requirement of low energy consumption for air capture. The carbon capture material also has the advantages of simple preparation method, low raw material and preparation cost, easy mass production and the like, and has a wide popularization and application prospect.

Description

A Highly Efficient Solid Atmospheric Carbon Capture Material, Its Preparation Method and Application Technical Field

[0001] This invention belongs to the field of carbon dioxide emission reduction technology, specifically relating to a highly efficient solid atmospheric carbon capture material and its preparation method, as well as the application of the above-mentioned highly efficient solid atmospheric carbon capture material in direct carbon dioxide air capture. Background Technology

[0002] Since the Industrial Revolution, global warming caused by greenhouse gas emissions has become increasingly serious, with changes in atmospheric CO2 concentration considered to be most closely related to global warming. Direct air capture (DAC), as a carbon-negative emission technology (a technology that removes CO2 from the atmosphere by increasing natural carbon sinks or using chemical methods) and a safety net technology, has received increasing attention from academia and industry.

[0003] Compared to solution-based absorption DAC technology, solid-state adsorption DAC technology avoids water loss due to partial evaporation during absorbent heating and heat loss due to the absorption of latent heat of vaporization by this evaporated water. It also offers significant advantages in reducing equipment corrosion and improving the adsorbent's resistance to degradation. Solid adsorbents mainly include alkali metal-based adsorbents, metal-organic frameworks (MOFs) adsorbents, supported amine adsorbents, and humidifying adsorbents. Solid amine adsorbents' capture of low-concentration CO2 is limited by CO2 kinetic diffusion, resulting in relatively low adsorption performance and amine utilization, and the carrier preparation process is complex. MOFs adsorbents exhibit poor selectivity for CO2 and water stability. Humidifying adsorbents have limited carrier types and low adsorption capacity. Overall, alkali metal-based solid adsorbents combine the advantages of both chemical and physical adsorption methods, enabling rapid and efficient reaction with CO2 while avoiding equipment corrosion and regeneration energy consumption issues caused by wet operations.

[0004] Previous research has shown that potassium-based adsorbents exhibit higher carbonation reactivity than sodium-based adsorbents, are less prone to deactivation, and maintain high activity even after multiple cycles. This enables rapid and efficient capture of CO2 from the air, making it more suitable for the industrial application of alkali metal-based solid adsorbent DAC technology. However, potassium-based solid adsorbents suffer from drawbacks when capturing CO2 from flue gas, including high carbonation reaction temperatures and high regeneration energy consumption. When capturing extremely low concentrations of CO2 from the air, they face challenges such as complex and time-consuming carrier preparation processes, high regeneration energy consumption, and low cycle efficiency, impacting the economic viability of air capture. Some studies have indicated that selecting suitable carriers can help reduce the thermal regeneration temperature and energy consumption of the adsorbent; however, the adsorption capacity of the resulting adsorbents still needs improvement, limiting their application in direct carbon dioxide air capture.

[0005] Based on this, a solid atmospheric carbon capture material with high adsorption capacity and low regeneration temperature and its preparation method are provided to meet the needs of direct carbon dioxide capture in the air. This is of great significance for suppressing sea level rise, ocean warming and acidification, and is also a technical problem that urgently needs to be solved. Summary of the Invention

[0006] One of the objectives of this invention is to provide a method for preparing a highly efficient solid atmospheric carbon capture material with high adsorption capacity and low regeneration temperature, which can meet the requirements of direct air capture.

[0007] The second objective of this invention is to provide a highly efficient solid atmospheric carbon capture material with high adsorption capacity and low regeneration temperature, which can meet the requirements of direct air capture.

[0008] The third objective of this invention is to provide an application of a highly efficient solid atmospheric carbon capture material in the direct air capture of carbon dioxide.

[0009] One of the technical solutions adopted to achieve the objective of this invention is: to provide a method for preparing a highly efficient solid atmospheric carbon capture material, comprising the following steps:

[0010] S1. Add a titanate crosslinking agent to an organic solvent to obtain an impregnation solution with a titanium ion concentration of 0.25–1 mol / L;

[0011] S2. The zirconium dioxide support is added to the impregnation solution and fully impregnated. The impregnated support is then dried, calcined, and ground to obtain the first product.

[0012] S3. The first product is added to an aqueous solution of potassium carbonate with a concentration of 0.9-1.2 mol / L for thorough impregnation. The impregnated first product is then dried, calcined, ground, and sieved to obtain a high-efficiency solid atmospheric carbon capture material.

[0013] The overall concept of this invention for a high-efficiency solid atmospheric carbon capture material is as follows: To provide a solid atmospheric carbon capture material with high adsorption capacity and low regeneration temperature, capable of meeting the requirements of direct air capture, this invention optimizes the design of the types of carrier and active components, the types and amounts of doping modification materials, and the doping modification methods:

[0014] First, this invention uses zirconium oxide as a carrier for the active component potassium carbonate. Zirconium oxide can lower the reaction energy barrier, thereby reducing the adsorption and regeneration temperatures. It not only has a certain catalytic effect on the reaction and improves the cycle stability of the adsorbent, but also has significant advantages in reducing energy consumption.

[0015] Secondly, this invention uses titanate crosslinking agents as dopants to modify the adsorbent. On the one hand, titanate crosslinking agents can act as catalysts to enhance the surface density and heat resistance of zirconium dioxide. On the other hand, after high-temperature calcination, titanate crosslinking agents decompose to produce titanium dioxide. Titanium ions replace zirconium atoms, further increasing hydroxyl groups and promoting the carbonation reaction. Compared with the direct use of titanium dioxide, the adsorption capacity and cycle stability of potassium carbonate loaded on zirconium dioxide modified with titanate crosslinking agents are significantly improved.

[0016] Finally, the present invention employs a preparation method combining impregnation and calcination to enhance the binding effect between active components, dopants, and carriers, resulting in more uniform dispersion of each component. The carbon capture material obtained not only has high absorption capacity and low regeneration temperature, but also possesses excellent cycle stability, effectively meeting the requirements for direct air capture of carbon dioxide.

[0017] In step S1 of this invention, the titanium ion concentration in the impregnation solution directly affects the adsorption effect and cycle performance of the adsorbent. When the titanium ion concentration is too low, it cannot enhance the catalytic effect of zirconia; while when the titanium ion concentration is too high, it will affect the loading of the active component onto the zirconia support. Considering all these factors, the titanium ion concentration in the impregnation solution in step S1 is controlled to be 0.25–1 mol / L. Preferably, the titanium ion concentration in the impregnation solution is 0.6–0.8 mol / L.

[0018] Furthermore, in step S3, the concentration of potassium carbonate in the potassium carbonate solution determines the loading of the active component onto the carrier. If the potassium carbonate concentration is too low, the content of the active component will be low, resulting in a low carbon dioxide capture capacity. Conversely, if the potassium carbonate concentration is too high, it may clog the pores of the carrier, causing the carbonation reaction to remain only on the surface of the adsorbent, and the active component cannot achieve uniform distribution. Considering all these factors, the concentration of the potassium carbonate aqueous solution in step S3 is controlled to be 0.9–1.2 mol / L. Under these conditions, the loading of potassium carbonate in the carbon capture material is 10–13%.

[0019] Further, in step S1, the titanate crosslinking agent includes one or more combinations of tetrabutyl titanate, n-propyl titanate, isopropyl titanate, and tetraethyl titanate. Preferably, the titanate crosslinking agent is selected from tetrabutyl titanate.

[0020] Furthermore, in step S1, the organic solvent includes one or more combinations of ethanol, benzene, methanol, and diethyl ether. Preferably, ethanol is used as the organic solvent, as it has advantages over other solvents, such as better solubility, higher volatility, lower toxicity, and lower cost and availability.

[0021] Further, in step S2, the zirconium dioxide support is obtained by soaking, washing, drying, calcining, grinding, and sieving zirconium dioxide particles in deionized water. Preferably, the calcination temperature of the support is 300–400°C, and the time is 2–4 hours; the particle size of the zirconium dioxide support obtained after sieving is below 500 mesh. In this invention, washing and calcining the support can remove impurities contained in zirconium dioxide, which helps to activate the active sites on its surface.

[0022] Further, in step S2, the volume ratio of the impregnation solution to the zirconium dioxide support is 1.1–1.5:1. Under this range, the impregnation solution just covers the support, achieving sufficient impregnation to promote modification while avoiding waste of the titanate crosslinking agent. Preferably, the impregnation process is carried out at 30–35°C under stirring conditions for 8–24 hours.

[0023] Further, in step S2, the drying temperature is 90-110℃ and the time is 6-10h; the calcination includes a first calcination and a second calcination, the temperature of the first calcination is 300-350℃ and the time is 2-4h; the temperature of the second calcination is 400-450℃ and the time is 1-3h.

[0024] In this invention, a segmented temperature-controlled drying and calcination process is employed. The first stage of drying helps remove free water, while the second stage of calcination removes chemically bound water and volatile substances. After the gas escapes, it leaves pores in the adsorbent, increasing its internal surface area. The third stage of calcination further increases the adsorbent strength, controls the crystal structure, and increases the pore size and specific surface area of ​​the adsorbent. Studies have shown that the trapping material prepared using this segmented calcination process exhibits higher adsorbent strength and better stability.

[0025] Furthermore, during the calcination process, the heating rate should not be too fast, otherwise it will be detrimental to the formation and pore expansion of the trapping material. Preferably, the heating rate is 1-4°C / min.

[0026] Further, in step S3, the volume ratio of the potassium carbonate aqueous solution to the first product is 1.1–1.3:1. This invention employs an excess impregnation method, which facilitates thorough mixing of the carrier and the active component, improving the dispersion effect. Preferably, the impregnation process is carried out at 30–40°C under stirring conditions, and the impregnation time is 8–24 hours.

[0027] Further, in step S3, the drying temperature is 90-110℃ and the time is 6-10h; the calcination includes a third calcination and a fourth calcination, the third calcination temperature is 350-400℃ and the time is 2-4h; the fourth calcination temperature is 450-500℃ and the time is 1-3h.

[0028] In step S3 of this invention, segmented temperature-controlled drying and calcination are also employed, which helps to improve the binding force between the components, increase the adsorbent strength, control the crystal form, and increase the pore size and specific surface area of ​​the adsorbent. Furthermore, based on the differences in the impregnation solution composition, the calcination temperature in step S3 is slightly higher than that in step S2, which helps to achieve a higher binding strength between the active component and the carrier, a more uniform distribution, and easier formation of the adsorbent.

[0029] The second objective of this invention is to provide a highly efficient solid atmospheric carbon capture material prepared by the preparation method described in the first objective of this invention.

[0030] The carbonation reaction temperature of the high-efficiency solid atmospheric carbon capture material is 28–30℃, and the thermal regeneration reaction temperature is 140–150℃.

[0031] In a fixed-bed reactor, under conditions of an air flow rate of 500-1000 mL / min and an air carbon dioxide concentration of 390-450 ppm, the adsorption capacity of the highly efficient solid atmospheric carbon capture material for carbon dioxide was measured to be 0.32-0.64 mmol / g.

[0032] The third objective of this invention is to provide an application of the high-efficiency solid atmospheric carbon capture material described in the second objective of this invention in the direct air capture of carbon dioxide.

[0033] The high-efficiency solid atmospheric carbon capture material provided by this invention does not require the use of zirconium dioxide precursors; it directly uses finished zirconium dioxide for loading, and the total preparation time can be controlled within 2 days. The carbonation reaction temperature of the high-efficiency solid atmospheric carbon capture material prepared by this invention is 28–30°C, and the thermal regeneration reaction temperature is 140–150°C. A single cycle (including carbonation reaction, thermal regeneration, and post-regeneration cooling) can be completed within 6 hours, improving cycle efficiency. Furthermore, the preparation process of this carbon capture material first utilizes a titanate crosslinking agent for modification, and then loads the active component potassium carbonate, significantly improving the adsorption capacity.

[0034] The high-efficiency solid atmospheric carbon capture material prepared by this invention can achieve highly selective capture of carbon dioxide in the air under the two conditions of low carbon dioxide content (volume fraction 400-500 ppm) and low carbonation reaction temperature (28-30℃), which are both significantly disadvantageous in terms of reaction kinetics. Moreover, it is not affected by oxygen or rare gases in the air. It has good prospects for promotion and application in the field of direct air capture of carbon dioxide.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] (1) The present invention provides a method for preparing a high-efficiency solid atmospheric carbon capture material, which employs a multi-step impregnation and calcination technique to enhance the binding effect of active components, dopants, and carriers, and to achieve more uniform dispersion of each component. This preparation method uses moderately priced raw materials, is simple to implement, has high mechanical strength, and a long service life, making it suitable for fixed-bed reactions. The drying and calcination process consumes less energy than the traditional impregnation method, ensures uniform dispersion of active components, and allows for multiple recycling of adsorbent particles, significantly improving the adsorption efficiency of the fixed bed. This carbon capture material exhibits strong cycle stability and can be scaled up for industrial-scale mass production and application.

[0037] (2) The high-efficiency solid atmospheric carbon capture material prepared by this invention does not collide with each other, eliminating the risk of breakage and wear; the adsorbent particles can be recycled multiple times, and the adsorbent particles are stacked and filled with gaps between them, allowing airflow to pass smoothly between the particles without causing blockage. The adsorbent particles have pores inside, making it easy for air to enter the adsorbent particles and react.

[0038] (3) The high-efficiency solid atmospheric carbon capture material prepared by this invention uses potassium carbonate as the active component. Due to the chemical adsorption mechanism of alkali metals, the adsorbent has high adsorption selectivity for carbon dioxide. The presence of water vapor not only does not affect the structure of the adsorbent, but also increases the adsorption capacity as a reactant. The addition of titanate crosslinking agents in the carrier increases the hydrophilicity of the adsorbent surface, regulates the dispersion of the active component on the carrier surface, improves the adsorption capacity of the adsorbent, and lowers the carbonation reaction energy barrier, achieving air capture at 30°C. Furthermore, the desorption regeneration temperature is reduced to 150°C, further reducing energy consumption and meeting the economic feasibility of direct air capture. It can be combined with CCUS (carbon capture, utilization and storage) technology to further store and utilize carbon dioxide. It has broad prospects for promotion and application. Attached Figure Description

[0039] Figure 1 is a schematic flowchart of a method for preparing a high-efficiency solid atmospheric carbon capture material according to an embodiment of the present invention;

[0040] Figure 2 is a scanning electron microscope image of the high-efficiency solid atmospheric carbon capture material prepared in Example 2 of the present invention;

[0041] Figure 3 is a cyclic adsorption capacity diagram of the high-efficiency potassium-based solid carbon dioxide chemisorbent prepared in Example 2 of the present invention. Detailed Implementation

[0042] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0044] This invention provides a method for preparing a highly efficient solid atmospheric carbon capture material. A schematic flowchart is shown in Figure 1. The preparation method mainly includes the following steps:

[0045] Step 1: Soak and wash the zirconium dioxide particles in deionized water exceeding their volume, dry them, and then calcine them at a temperature of 300-400℃ for 2-4 hours. Grind and sieve the product to obtain the zirconium dioxide carrier.

[0046] Step 2: Add a titanate crosslinking agent (one or more of tetrabutyl titanate, n-propyl titanate, isopropyl titanate and tetraethyl titanate) to an organic solvent (one or more of ethanol, benzene, methanol and diethyl ether) to obtain an impregnation solution with a titanium ion concentration of 0.25 to 1 mol / L.

[0047] Step 3: The zirconium dioxide support is added to the impregnation solution and fully impregnated. The impregnation process is carried out at 30-35°C under stirring conditions for 8-24 hours. The volume ratio of the impregnation solution to the zirconium dioxide support is 1.1-1.5:1. The impregnated support is dried at 90-110°C for 6-10 hours, then calcined at 300-350°C for 2-4 hours, and then calcined at 400-450°C for 1-3 hours. The product is then ground to obtain the first product.

[0048] Step 4: The first product is added to a potassium carbonate solution (potassium carbonate concentration of 0.9-1.2 mol / L) for thorough impregnation. The impregnation process is carried out at 30-40°C with stirring for 8-24 hours. The volume ratio of potassium carbonate solution to the first product is controlled at 1.1-1.3:1. The impregnated first product is dried at 90-110°C for 6-10 hours, then calcined at 350-400°C for 2-4 hours, and then calcined at 450-500°C for 1-3 hours. The product is then ground and sieved to obtain the adsorbent material (i.e., high-efficiency solid atmospheric carbon capture material).

[0049] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0050] Example 1:

[0051] Step 1: Weigh 10g of micron-sized zirconia support (average diameter approximately 2μm) into a 500mL glass beaker, add 400mL of deionized water, let stand for 1 hour, filter dry, and repeat the water washing step once. Place the filtered support microspheres in a flat-bottomed quartz crucible and calcine at 500℃ for 3 hours in a muffle furnace. After cooling to room temperature, remove and grind with a mortar and pestle until sieved to below 500 mesh.

[0052] Step 2: Measure 10 mL of ethanol into a 25 mL glass beaker, add a certain amount of tetrabutyl titanate and stir thoroughly to ensure that the titanium ion concentration is 0.27 mol / L.

[0053] Step 3: Add 10g of pretreated zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation liquid to carrier powder is 1.1:1). After impregnation at 30-35℃, stir the impregnation liquid with a magnetic stirrer for 10 hours, then dry it in a muffle furnace at 110℃ for 8 hours, calcine it at 300℃ for 3 hours, and calcine it at 450℃ for 2 hours. After cooling to room temperature, remove it and grind it with an agate mortar and pestle until it is sieved to below 500 mesh.

[0054] Step 4: Measure 10 mL of deionized water into a 25 mL glass beaker, add a certain amount of potassium carbonate and stir thoroughly until clear and transparent, ensuring the potassium carbonate solution concentration is 1 mol / L. Add 10 g of modified zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation solution to modified carrier powder is 1.2:1). The impregnation process takes place entirely in a water bath at a temperature controlled at 30-40℃. After impregnation, stir the impregnation solution with a magnetic stirrer for 10 hours, then gradually increase the temperature to 85℃ and stir until the water is almost completely evaporated. Afterward, perform a segmented drying and calcination process with the following parameters: drying at 110℃ for 8 hours, calcining at 380℃ for 3 hours, and calcining at 500℃ for 2 hours, with a heating rate of 4℃ / min. After cooling to room temperature, remove the material and grind it using an agate mortar and pestle until it is sieved to below 500 mesh to obtain the adsorbent material (i.e., a high-efficiency solid atmospheric carbon capture material). The theoretical loading of K2CO3 is 10%–13%, while the actual loading of K2CO3 in the characterization test was 12.28%.

[0055] Example 2:

[0056] Step 1: Weigh 10g of micron-sized zirconia support (average diameter approximately 2μm) into a 500mL glass beaker, add 400mL of deionized water, let stand for 1 hour, filter dry, and repeat the water washing step once. Place the filtered support microspheres in a flat-bottomed quartz crucible and calcine at 500℃ for 3 hours in a muffle furnace. After cooling to room temperature, remove and grind with a mortar and pestle until sieved to below 500 mesh.

[0057] Step 2: Measure 10 mL of ethanol into a 25 mL glass beaker, add a certain amount of tetrabutyl titanate and stir thoroughly to ensure that the titanium ion concentration is 0.68 mol / L.

[0058] Step 3: Add 10g of pretreated zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation liquid to carrier powder is 1.3:1). After impregnation at 30-35℃, stir the impregnation liquid with a magnetic stirrer for 10 hours, then dry it in a muffle furnace at 110℃ for 8 hours, calcine it at 300℃ for 3 hours, and calcine it at 450℃ for 2 hours. After cooling to room temperature, remove it and grind it with an agate mortar and pestle until it is sieved to below 500 mesh.

[0059] Step 4: Measure 10 mL of deionized water into a 25 mL glass beaker, add a certain amount of potassium carbonate and stir thoroughly until clear and transparent, ensuring the potassium carbonate solution concentration is 1 mol / L. Add 10 g of modified zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation solution to modified carrier powder is 1.2:1). The impregnation process takes place entirely in a water bath at a temperature controlled at 30-40℃. After impregnation, stir the impregnation solution with a magnetic stirrer for 10 hours, then gradually increase the temperature to 85℃ and stir until the water is almost completely evaporated. Afterward, perform a segmented drying and calcination process with the following parameters: drying at 110℃ for 8 hours, calcining at 380℃ for 3 hours, and calcining at 500℃ for 2 hours, with a heating rate of 4℃ / min. After cooling to room temperature, remove the material and grind it using an agate mortar and pestle until it is sieved to below 500 mesh to obtain the adsorbent material (i.e., a high-efficiency solid atmospheric carbon capture material). The theoretical loading of K2CO3 is 10%–13%, while the actual loading of K2CO3 in the characterization test is 10.54%.

[0060] Figure 2 is a scanning electron microscope (SEM) image of the adsorbent prepared in Example 2 of this invention. As can be seen from Figure 2, the adsorbent prepared in this invention has a rough, wrinkled surface, large particle size, is loose and porous, and has numerous and wide pores. The pore structure is relatively good, with some agglomeration, and the particles themselves contain pores of different sizes. The specific surface area and pore volume of the adsorbent are reduced compared to zirconium dioxide, indicating that the densely packed micropores are covered by K₂CO₃. Gas-solid reactions readily occur on both the surface and in the bulk phase.

[0061] Example 3:

[0062] Step 1: Weigh 10g of micron-sized zirconia support (average diameter approximately 2μm) into a 500mL glass beaker, add 400mL of deionized water, let stand for 1 hour, filter dry, and repeat the water washing step once. Place the filtered support microspheres in a flat-bottomed quartz crucible and calcine at 500℃ for 3 hours in a muffle furnace. After cooling to room temperature, remove and grind with a mortar and pestle until sieved to below 500 mesh.

[0063] Step 2: Measure 10 mL of ethanol into 25 mL glass beakers, add a certain amount of tetrabutyl titanate and stir thoroughly to ensure that the titanium ion concentration is 0.98 mol / L.

[0064] Step 3: Add 10g of pretreated zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation liquid to carrier powder is 1.5:1). After impregnation at 30-35℃, stir the impregnation liquid with a magnetic stirrer for 10 hours, then dry it in a muffle furnace at 110℃ for 8 hours, calcine it at 300℃ for 3 hours, and calcine it at 450℃ for 2 hours. After cooling to room temperature, remove it and grind it with an agate mortar and pestle until it is sieved to below 500 mesh.

[0065] Step 4: Measure 10 mL of deionized water into a 25 mL glass beaker, add a certain amount of potassium carbonate and stir thoroughly until clear and transparent, ensuring the potassium carbonate solution concentration is 1 mol / L. Add 10 g of modified zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation solution to modified carrier powder is 1.2:1). The impregnation process takes place entirely in a water bath at a temperature controlled at 30-40℃. After impregnation, stir the impregnation solution with a magnetic stirrer for 10 hours, then gradually increase the temperature to 85℃ and stir until the water is almost completely evaporated. Afterward, perform a segmented drying and calcination process with the following parameters: drying at 110℃ for 8 hours, calcining at 380℃ for 3 hours, and calcining at 500℃ for 2 hours, with a heating rate of 4℃ / min. After cooling to room temperature, remove the material and grind it using an agate mortar and pestle until it is sieved to below 500 mesh to obtain the adsorbent material (i.e., a high-efficiency solid atmospheric carbon capture material). The theoretical loading of K2CO3 is 10%–13%, while the actual loading of K2CO3 in the characterization test is 12.35%.

[0066] Example 4

[0067] Step 1: Weigh 10g of micron-sized zirconia support (average diameter approximately 2μm) into a 500mL glass beaker, add 400mL of deionized water, let stand for 1 hour, filter dry, and repeat the water washing step once. Place the filtered support microspheres in a flat-bottomed quartz crucible and calcine at 500℃ for 3 hours in a muffle furnace. After cooling to room temperature, remove and grind with a mortar and pestle until sieved to below 500 mesh.

[0068] Step 2: Measure 10 mL of methanol into a 25 mL glass beaker, add a certain amount of tetrapropyl titanate and stir thoroughly to ensure that the titanium ion concentration is 0.72 mol / L.

[0069] Step 3: Add 10g of pretreated zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation liquid to carrier powder is 1.5:1). After impregnation at 30-35℃, stir the impregnation liquid with a magnetic stirrer for 10 hours, then dry it in a muffle furnace at 110℃ for 8 hours, calcine it at 300℃ for 3 hours, and calcine it at 400℃ for 2 hours. After cooling to room temperature, remove it and grind it with an agate mortar and pestle until it is sieved to below 500 mesh.

[0070] Step 4: Measure 10 mL of deionized water into a 25 mL glass beaker, add a certain amount of potassium carbonate and stir thoroughly until clear and transparent, ensuring the potassium carbonate solution concentration is 1 mol / L. Add 10 g of modified zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation solution to modified carrier powder is 1.3:1). The impregnation process takes place entirely in a water bath at a temperature controlled at 35-40℃. After impregnation, stir the impregnation solution with a magnetic stirrer for 10 hours, then gradually increase the temperature to 90℃ and stir until the water is almost completely evaporated. Afterward, perform a segmented drying and calcination process with the following parameters: drying at 110℃ for 8 hours, calcining at 380℃ for 3 hours, and calcining at 450℃ for 2 hours, with a heating rate of 4℃ / min. After cooling to room temperature, remove the material and grind it using an agate mortar and pestle until it is sieved to below 500 mesh to obtain the adsorbent material (i.e., a high-efficiency solid atmospheric carbon capture material).

[0071] Example 5

[0072] Step 1: Weigh 10g of micron-sized zirconia support (average diameter approximately 2μm) into a 500mL glass beaker, add 400mL of deionized water, let stand for 1 hour, filter dry, and repeat the water washing step once. Place the filtered support microspheres in a flat-bottomed quartz crucible and calcine at 500℃ for 3 hours in a muffle furnace. After cooling to room temperature, remove and grind with a mortar and pestle until sieved to below 500 mesh.

[0073] Step 2: Measure 10 mL of diethyl ether into 25 mL glass beakers, add a certain amount of tetraethyl titanate and stir thoroughly to ensure that the titanium ion concentration is 0.98 mol / L.

[0074] Step 3: Add 10g of pretreated zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation liquid to carrier powder is 1.5:1). After impregnation at 30-35℃, stir the impregnation liquid with a magnetic stirrer for 10 hours, then dry it in a muffle furnace at 110℃ for 8 hours, calcine it at 300℃ for 3 hours, and calcine it at 400℃ for 2 hours. After cooling to room temperature, remove it and grind it with an agate mortar and pestle until it is sieved to below 500 mesh.

[0075] Step 4: Measure 10 mL of deionized water into a 25 mL glass beaker, add a certain amount of potassium carbonate and stir thoroughly until clear and transparent, ensuring the potassium carbonate solution concentration is 1 mol / L. Add 10 g of modified zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation solution to modified carrier powder is 1.2:1). The impregnation process takes place entirely in a water bath at a temperature controlled at 30-40℃. After impregnation, stir the impregnation solution with a magnetic stirrer for 10 hours, then gradually increase the temperature to 85℃ and stir until the water is almost completely evaporated. Afterward, perform a segmented drying and calcination process with the following parameters: drying at 110℃ for 8 hours, calcining at 350℃ for 3 hours, and calcining at 500℃ for 2 hours, with a heating rate of 3℃ / min. After cooling to room temperature, remove the material and grind it using an agate mortar and pestle until it is sieved to below 500 mesh to obtain the adsorbent material (i.e., a high-efficiency solid atmospheric carbon capture material).

[0076] Comparative Example 1

[0077] Step 1: Weigh 10g of micron-sized zirconia support (average diameter approximately 2μm) into a 500mL glass beaker, add 400mL of deionized water, let stand for 1 hour, filter dry, and repeat the water washing step 1 once. Place the filtered support microspheres in a flat-bottomed quartz crucible and calcine at 500℃ for 3 hours in a muffle furnace. After cooling to room temperature, remove and grind with a mortar and pestle until sieved to below 500 mesh.

[0078] Step 2: Measure 10 mL of deionized water into three 25 mL glass beakers, add a certain amount of potassium carbonate, and stir thoroughly until clear and transparent to prepare impregnation solutions with potassium carbonate concentrations of 0.6 mol / L, 1 mol / L, and 1.5 mol / L, respectively. Add 10 g of unmodified zirconium dioxide powder to each of the three beakers and stir to form a slurry (the volume ratio of impregnation solution to modified carrier powder is 1.2:1). The entire impregnation process takes place in a water bath at a temperature controlled at 30-40℃. After impregnation, stir the impregnation solution with a magnetic stirrer for 10 hours, then gradually increase the temperature to 85℃ and stir until the water is almost completely evaporated. Then, perform a segmented drying and calcination process with the following parameters: drying at 110℃ for 8 hours, calcining at 380℃ for 3 hours, and calcining at 500℃ for 2-3 hours, with a heating rate of 4℃ / min. After cooling to room temperature, remove the product and grind it using an agate mortar and pestle until it is sieved to below 500 mesh to obtain the adsorbent.

[0079] Three groups of adsorbents were prepared in this comparative example. The theoretical loading of K2CO3 was 7%, 11%, and 16%, respectively, and the actual loading of K2CO3 was 6.44%, 10.65%, and 16.84%, respectively, according to characterization tests.

[0080] Comparative Example 2

[0081] Step 1: Weigh 10g of micron-sized zirconia support (average diameter approximately 2μm) into a 500mL glass beaker, add 400mL of deionized water, let stand for 1 hour, filter dry, and repeat the water washing step once. Place the filtered support microspheres in a flat-bottomed quartz crucible and calcine at 500℃ for 3 hours in a muffle furnace. After cooling to room temperature, remove and grind with a mortar and pestle until sieved to below 500 mesh.

[0082] Step 2: Measure 10 mL of deionized water into a 25 mL glass beaker, add a certain amount of potassium carbonate and stir thoroughly until clear and transparent, ensuring the potassium carbonate solution concentration is 1 mol / L. Add 10 g of unmodified zirconium dioxide powder and stir to form a slurry (the volume ratio of impregnation solution to modified carrier powder is 1.2:1). The impregnation process takes place entirely in a water bath at a temperature controlled at 30-40℃. After impregnation, stir the impregnation solution with a magnetic stirrer for 10 hours to obtain the first product.

[0083] Step 3: Add 0.8g of TiO2 powder to the first product, and continue stirring the impregnation solution with a magnetic stirrer for 5 hours. Then, gradually increase the temperature to 85℃ and stir until the moisture is basically evaporated. Next, perform segmented drying and calcination with the following parameters: drying at 110℃ for 8 hours, calcining at 380℃ for 3 hours, and calcining at 500℃ for 2-3 hours, with a heating rate of 4℃ / min. After cooling to room temperature, remove the product and grind it in an agate mortar until it is sieved to below 500 mesh to obtain the adsorbent. The theoretical loading of K2CO3 is 10%–13%.

[0084] Performance testing

[0085] The adsorption and cycling performance of the adsorbents (carbon capture materials) prepared in each embodiment and comparative example were tested using a fixed-bed test platform.

[0086] The fixed-bed test platform mainly consists of three parts: a gas path system, a reactor system, and a data acquisition system. The reactor system comprises a fixed bed body (20mm inner diameter) and a condenser. The fixed bed body is electrically heated to meet the temperature requirements of the absorption-regeneration process. The data acquisition system consists of a Fuji ZRE gas analyzer and a matching recorder, with a data testing accuracy of 0.0005 vol%. The analyzer's range is 0-1000 ppm and 1-10%, with a recording interval of 1 second. The N2 required for the reaction is supplied by cylinder gas with a purity of 99.9 vol%. The gas flow rate is controlled by a Qixing mass flow meter (range 0-1000 ml / min) in conjunction with a D08-3F flow display instrument.

[0087] A miniature diaphragm pump (maximum flow rate under no-load 7.2 L / min) introduces air with a CO2 concentration of 390-450 ppm into the fixed-bed reactor at a flow rate of 500-1000 ml / min. A saturator filled with deionized water (1000 ml capacity) is used to control the relative humidity (RH) of the inlet air, which is measured using a temperature and humidity transmitter (accuracy 0.3℃; 2% RH). The fixed-bed reactor body is a 20 mm inner diameter, 400 mm long stainless steel tube. 2 g of adsorbent sample is placed inside the bed, mixed with 10 g of inert quartz sand with a particle size of 120-150 μm to increase the bed height and slow down the bed temperature rise during the adsorption reaction. The bed material is supported by degreased cotton and placed at the thermocouple in the middle of the reactor. The exhaust gas from the fixed bed outlet is condensed to remove water before entering a gas analyzer, recording the CO2 volume concentration every second. The decarbonization effect of the absorbent is assessed by detecting the CO2 content. Both the gas inlet temperature and the fixed-bed reactor bed temperature are kept warm by electric heating and controlled by a temperature control system, which both preheats the reaction gas and prevents water vapor condensation.

[0088] The formula for calculating the CO2 adsorption rate C is as follows:

[0089]

[0090] The total gas flow rate during the adsorption stage is Q1 (ml / min), the volume concentration of air other than CO2 at the reactor inlet during the adsorption stage is M (vol%), the CO2 volume concentration at the reactor outlet in the empty bed experiment (without adsorbent and only inert material) is X (vol%), and the CO2 volume concentration at the reactor outlet in the adsorption experiment is Y (vol%), where m is the mass of the sample (g). m is the molar volume of the ideal gas (24 L / mol, T = 303 K, P = 1 bar), and m is the mass of the composite adsorbent [g].

[0091] CO2 thermal regeneration rate at time t The calculation formula is as follows:

[0092]

[0093] The total gas flow rate during the regeneration stage is Q3 (ml / min), and the CO2 volume concentration at the reactor outlet during the regeneration experiment is Z (vol%).

[0094] The formula for calculating CO2 adsorption capacity / regeneration capacity (E) is as follows:

[0095]

[0096] (I) Adsorption capacity test

[0097] The adsorbents (i.e., carbon capture materials) prepared in Examples 1-3 and the comparative examples of this invention were subjected to carbonation reaction at 30°C and thermal regeneration reaction at 150°C. The adsorption capacity of each adsorbent for carbon dioxide was tested, and the results are shown in Table 1 below:

[0098] Table 1

[0099]

[0100] It can be seen from Table 1 above that

[0101] The test results of the three sets of Comparative Example 1 show that the adsorption capacities are similar when the theoretical K2CO3 loading is 7% and 16%, approximately 0.17–0.18 mmol / g. The highest carbon dioxide adsorption capacity, approximately 0.23 mmol / g, is achieved when the K2CO3 loading is 11%. Therefore, in all embodiments, the modified adsorbent was designed with a K2CO3 loading of 10%–13%.

[0102] Compared to Comparative Example 1, under the premise of similar K2CO3 loading (10%–13%), the adsorption capacity of the adsorbents modified with tetrabutyl titanate in Examples 1–3 was significantly improved. Furthermore, the adsorbent prepared in Example 2 exhibited a higher adsorption capacity compared to Examples 1 and 3. This indicates that the concentration of titanium ions in the titanium-containing impregnation solution has a significant impact on improving the adsorption capacity of the adsorbent.

[0103] Furthermore, in Comparative Example 2, titanium dioxide was directly used as a dopant to modify the adsorbent, but the expected modification effect was not achieved. This indicates that in this invention, a precursor such as a titanate crosslinking agent is required as a dopant to effectively improve the adsorption capacity and cycling stability of the adsorbent.

[0104] (II) Adsorption Cycling Performance Test

[0105] The adsorbent prepared in Example 2 of this invention was subjected to adsorption cycle tests. Carbonation was carried out at 30°C, and thermal regeneration was carried out at 150°C. A total of thirteen cycles were performed on the KZCHT11-2 type adsorbent, and the adsorption cycle performance is shown in Figure 3. As can be seen from Figure 3, after 7 cycles, the adsorption capacity of the KZCHT11-2 type adsorbent remained stable at approximately 0.45 mmol / g.

[0106] In summary, this invention uses titanate crosslinking agents as dopants and excessive impregnation of zirconium dioxide with a carrier to obtain a composite carrier. Then, through programmed temperature calcination, the chemical bonding between the dopant and the carrier and the stability of the carrier's pore structure are ensured. Subsequently, potassium carbonate is loaded onto the surface of the carrier, which increases the number of active sites on the adsorbent surface, thereby increasing the adsorption capacity and cycle stability of the adsorbent.

[0107] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. An application of a high-efficiency solid atmospheric carbon capture material in direct carbon dioxide air capture, characterized in that, The carbonation reaction temperature of the high-efficiency solid carbon capture material is 28~30℃; the preparation method of the high-efficiency solid carbon capture material includes the following steps: S1, adding a titanate crosslinking agent to an organic solvent to obtain an impregnation solution with a titanium ion concentration of 0.25~1mol / L; S2, adding a zirconium dioxide support to the impregnation solution for thorough impregnation, wherein the volume ratio of the impregnation solution to the zirconium dioxide support is 1.1~1.5:1; drying, first calcining, second calcining, and grinding the impregnated support to obtain a first product; the temperature of the first calcination is 300~350℃. The first product is subjected to a second calcination at 400-450℃ for 1-3 hours. The second calcination is carried out at 400-450℃ for 1-3 hours. The first product is then fully impregnated in an aqueous solution of potassium carbonate with a concentration of 0.9-1.2 mol / L, with the volume ratio of the potassium carbonate solution to the first product being 1.1-1.3:

1. The impregnated first product is then dried, subjected to a third calcination, a fourth calcination, ground, and sieved to obtain a high-efficiency solid atmospheric carbon capture material. The third calcination is carried out at 350-400℃ for 2-4 hours, and the fourth calcination is carried out at 450-500℃ for 1-3 hours.

2. The application according to claim 1, characterized in that, In step S1, the titanate crosslinking agent includes one or more of tetrabutyl titanate, n-propyl titanate, isopropyl titanate, and tetraethyl titanate.

3. The application according to claim 1, characterized in that, In step S1, the organic solvent includes one or more of ethanol, benzene, methanol, and diethyl ether.

4. The application according to claim 1, characterized in that, In step S2, the zirconium dioxide carrier is prepared by soaking, washing, drying, calcining, grinding and sieving zirconium dioxide particles in deionized water.

5. The application according to claim 1, characterized in that, In step S2, the drying temperature is 90~110℃ and the time is 6~10h.

6. The application according to claim 1, characterized in that, In step S3, the drying temperature is 90~110℃ and the time is 6~10h.

7. The application according to claim 1, characterized in that, The thermal regeneration reaction temperature of the high-efficiency solid atmospheric carbon capture material is 140~150℃.

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