Preparation method and application of CO2 adsorption material

Abstract

The invention provides a preparation method and application of a CO2 adsorption material. The CO2 adsorption material prepared by adopting the preparation method disclosed by the invention is low in ash content and has relatively high carbon dioxide adsorption capacity and CO2 / N2 selectivity. The preparation method comprises the following steps: (1) mixing a basic raw material with an activating agent containing alkali metal elements, and uniformly grinding to obtain a mixture; the basic raw material is one or more of coal and related products of the coal; (2) heating the mixture to 300-400 DEG C under a protective atmosphere or a vacuum condition, and carrying out heat preservation; then raising the temperature to 600-800 DEG C and carrying out heat preservation to obtain a carbonized and activated sample; (3) putting the carbonized and activated sample into an aqueous solution or an alkaline solution containing alkali metal ions, and carrying out heat treatment at 50-80 DEG C, wherein the heat treatment is carried out under the condition of ultrasonic waves and / or bubbling by introducing gas; and washing with water and drying to obtain the CO2 adsorption material.

Description

Technical Field

[0001] This invention relates to the field of CO2 adsorption and capture technology, specifically to a method for preparing and applying a CO2 adsorption material. Background Technology

[0002] Adsorption-based carbon capture technology is considered the most promising second-generation capture technology due to its significant potential for energy and overall cost reduction, environmental friendliness, and minimal equipment corrosion. Developing low-cost, high-capacity CO2 adsorbents is key to reducing the energy consumption and cost of adsorption-based carbon capture technology. Carbon-based adsorbents, with their large specific surface area, well-developed pore structure, low cost, simple preparation, and good stability, are well-suited for large-scale carbon capture; however, they have long suffered from the critical problems of low CO2 adsorption capacity and poor selectivity.

[0003] Chinese patent CN113428854B discloses a method for preparing lignocellulosic porous carbon materials for CO2 adsorption. Compared with traditional activation methods, this method uses a one-step site-directed activation strategy to prepare lignocellulosic porous carbon materials. The amount of KOH activator used is only 1 / 6 to 1 / 10 of that used in traditional methods. This allows for the controlled regulation of the pore structure and distribution of the lignocellulosic carbon material through a trace amount of activator, thus achieving the directional preparation of CO2 gas adsorption materials. This porous carbon material possesses a main peak pore size that is compatible with the kinetic dimensions of CO2, resulting in an adsorption capacity of 5.21 mmol g / L when applied to CO2 adsorption. -1 (0℃, 1 atm) and 3.54 mmol g -1 This method exhibits excellent CO2 adsorption capacity (25℃, 1 atm) and good cycle reversibility. However, it uses a large amount of organic solvents and reagents, and the CO2 adsorption capacity of the material is still relatively low, making it unsuitable for large-scale carbon capture technology applications.

[0004] Chinese patent CN104445134B discloses a method for surface modification of carbon materials. This method utilizes a safe, low-cost, non-toxic, and environmentally friendly structure-directing agent. Through a one-pot hydrothermal method, functionalized groups are simply and efficiently introduced onto the surface of carbon nanotubes and graphene. This not only significantly modifies the surface of the carbon materials but also maximizes the stability of their structure, improves their dispersibility in solution, and significantly enhances the mechanical and electrical properties of the composite materials. This method is simple, efficient, safe, environmentally friendly, and easily scalable for production. Summary of the Invention

[0005] To address at least one deficiency in the existing technology, the present invention provides a method for preparing CO2 adsorbent materials and their applications. The CO2 adsorbent materials prepared by the method of the present invention have low ash content and high carbon dioxide adsorption capacity and CO2 / N2 selectivity.

[0006] To achieve its objective, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing a CO2 adsorbent material, comprising the following steps:

[0008] (1) The basic raw materials are mixed with an activator containing alkali metal elements and ground evenly to obtain a mixture; the basic raw materials are one or more of coal and coal-related products;

[0009] (2) The mixture is first heated to 300-400℃ and kept at that temperature under a protective atmosphere or vacuum; then heated to 600-800℃ and kept at that temperature to obtain a carbonized and activated sample.

[0010] (3) The carbonized and activated sample is placed in an aqueous solution or an alkaline solution containing alkali metal ions and heat-treated at 50-80°C, and the heat treatment is carried out under ultrasonic and / or gas bubbling conditions; then washed with water and dried to obtain the CO2 adsorbent material.

[0011] In some embodiments, the coal-related products are selected from one or more of coal liquefaction residue and coal tar pitch;

[0012] And / or, the activator is selected from one or more of potassium hydroxide, potassium carbonate, sodium hydroxide, and sodium carbonate.

[0013] Preferably, the mass ratio of the base material to the activator is 1:(0.5-4).

[0014] In some embodiments, in step (2), the protective atmosphere is nitrogen, argon and / or waste gas.

[0015] In some embodiments, in step (2), the heating rate to 300-400°C is 1-10°C / min;

[0016] And / or, the heating rate to 600-800℃ is 1-10℃ / min;

[0017] And / or, after heating to 300-400℃ in step (2), keep warm for 1-2 hours;

[0018] And / or, after heating to 600-800℃ in step (2), keep warm for 0.5-4 hours.

[0019] In some embodiments, in step (3), the concentration of the alkaline solution is 1-5 mol / L, preferably 2-3 mol / L;

[0020] Preferably, the alkaline solution is an aqueous solution of potassium hydroxide and / or sodium hydroxide.

[0021] In some implementations, the heat treatment in step (3) takes 0.5-6 hours.

[0022] Preferably, the heat treatment temperature is 70-80°C;

[0023] And / or, the ultrasonic frequency of the ultrasound is 40-80 Hz;

[0024] And / or, the gas introduced through the bubbling is one or more of compressed air, nitrogen, and O2, preferably O2;

[0025] And / or, step (2) is performed in a tubular furnace;

[0026] And / or, in step (1), the basic raw material is pre-crushed to below 200 mesh.

[0027] In a preferred embodiment, the heat treatment is performed under conditions of ultrasound and bubbling with introduced gas.

[0028] The present invention also provides the application of the CO2 adsorbent material prepared by the above preparation method in CO2 adsorption.

[0029] The technical solution provided by this invention has the following beneficial effects:

[0030] The preparation method of this invention uses coal and / or its related products as a carbon source. First, the activator and the basic raw materials are mixed by solid-phase mixing and pretreated at a low temperature of 300-400℃. Then, high-temperature carbonization activation is carried out at 600-800℃. Then, heat treatment is carried out in an aqueous or alkaline solution at 50-80℃ by "ultrasound and / or bubbling". The acid washing operation can be omitted, and a CO2 adsorption material with low ash content, high CO2 adsorption capacity and high CO2 / N2 selectivity can be obtained. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the preparation process route for CO2 adsorption materials in some embodiments;

[0032] Figure 2 This is a schematic diagram of the "ultrasonic + bubbling" heat treatment process in some implementation methods;

[0033] Figure 3 This is a distribution map of K, Fe, and S elements in the adsorbent materials prepared in Example 1 and Comparative Example 1. The elemental distribution of the samples was observed using a JEOL JEMARM200F aberration-corrected transmission electron microscope (TEM) with an accelerating voltage of 200 kV.

[0034] Figure 4The image shows the pore size distribution of the adsorbent material obtained in Example 1. The physical adsorption of N2 (77K) was measured using a Micromeritics ASAP 2460 gas adsorption instrument manufactured by Micromeritics Instruments, Inc. The sample was degassed at 300°C for 4 hours. Detailed Implementation

[0035] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0037] This invention provides a method for preparing a CO2 adsorbent material, comprising the following steps:

[0038] (1) The basic raw materials are mixed with an activator containing alkali metal elements and ground evenly to obtain a mixture; the basic raw materials are one or more of coal and coal-related products;

[0039] (2) The mixture is first heated to 300-400℃ (e.g., 300℃, 350℃, 400℃, etc.) under a protective atmosphere or vacuum and kept at that temperature; then it is heated to 600-800℃ (e.g., 600℃, 650℃, 700℃, 750℃, 800℃, etc.) and kept at that temperature to obtain a carbonized and activated sample;

[0040] (3) The carbonized and activated sample is placed in an aqueous solution or an alkaline solution containing alkali metal ions and heat-treated at 50-80℃ (e.g., 50℃, 60℃, 70℃, 80℃, etc.), and the heat treatment is carried out under ultrasonic and / or gas bubbling conditions; then washed with water and dried to obtain the CO2 adsorbent material.

[0041] The preparation method of this invention uses coal and / or its related products as carbon sources. First, an ultra-microporous carbon material is formed through a one-pot carbonization and activation process. Then, the surface of the material is activated and modified through processes such as ultrasonic and / or bubbling heat treatment and water washing. This process can improve the surface activity of the material while effectively reducing the impurity content of the raw materials remaining in the adsorbent material, further improving the CO2 adsorption performance of the material. Finally, an ultra-microporous CO2 adsorbent material with high CO2 adsorption capacity, high CO2 / N2 selectivity, and physical adsorption as the core is prepared.

[0042] In some embodiments, the coal-related products are selected from one or more of coal liquefaction residues and coal tar pitch.

[0043] This invention uses coal and / or coal direct liquefaction byproducts such as coal tar pitch and / or coal liquefaction residue as raw materials. These materials are widely available and inexpensive. However, the high ash content of coal and its related products can affect the purity and performance of the final CO2 adsorption material. This invention first mixes the activator and basic raw materials using a solid-phase mixing method and pre-treats them at a low temperature of 300-400℃. Then, it performs high-temperature carbonization activation at 600-800℃ to remove volatile matter and other impurities from the raw materials. Next, it performs heat treatment in an aqueous or alkaline solution using "ultrasound and / or bubbling." This process not only removes residual impurities from the raw materials a second time, significantly improving the purity and adsorption performance of the material, but also creates an alkaline solution containing alkali metal ions by adding an aqueous or alkaline solution. This "ultrasound vibration and / or bubbling enhancement-alkaline heat impregnation" treatment effectively removes impurities while increasing the surface polarity of the material, thus improving its adsorption performance. The difference between this invention and existing conventional chemical activation methods for preparing carbon materials lies in its use of a "one-pot" method that combines carbonization and activation processes, optimizing the preparation process. Furthermore, it eliminates the need for acid washing after roasting and allows the use of residual metal elements in the roasted material as modifying elements during the ultrasonic and / or bubbling heat treatment process, improving the surface activity of the material and reducing the generation of waste acid, thus ensuring safety and environmental friendliness. The CO2 adsorbent material prepared by this invention exhibits excellent performance, and the preparation process is simple and low-cost, significantly reducing carbon capture costs while also enabling the clean and efficient utilization of coal.

[0044] In a preferred embodiment, the activator is selected from one or more of potassium hydroxide, potassium carbonate, sodium hydroxide, and sodium carbonate.

[0045] In a preferred embodiment, the mass ratio of the base material to the activator is 1:(0.5-4), such as 1:0.5, 1:1, 1:2, 1:3, 1:4, etc. Too little activator will result in incomplete activation of the material, underdeveloped pore structure, and poor adsorption effect; while too much activator will cause over-activation of the sample, resulting in collapse and destruction of the pore structure, and thus forming larger mesopores or macropores, which will reduce the CO2 adsorption performance of the material. Using the preferred mass ratio is beneficial to obtaining an adsorption material with better CO2 adsorption performance.

[0046] In some embodiments, in step (2), the protective atmosphere is nitrogen, argon and / or waste gas.

[0047] In this invention, during the carbonization activation step, the temperature is first raised to 300-400℃ for pretreatment; then, the temperature is raised to 600-800℃ for high-temperature carbonization activation. Pre-treatment at low temperature for a period of time allows for initial pore formation, followed by high-temperature carbonization at a relatively low temperature (no need to exceed 800℃). This method of low-temperature pretreatment followed by high-temperature carbonization activation facilitates the full decomposition of impurities such as volatiles from the raw coal / coal liquefaction residue / coal tar pitch, thereby improving the pore formation during subsequent high-temperature carbonization activation and enhancing the carbon dioxide adsorption performance of the resulting adsorbent material. In some embodiments, in step (2), the heating rate to 300-400℃ is 1-10℃ / min, for example, 1℃ / min, 3℃ / min, 5℃ / min, 7℃ / min, 10℃ / min, etc. In some embodiments, the heating rate to 600-800℃ is 1-10℃ / min, such as 1℃ / min, 3℃ / min, 5℃ / min, 7℃ / min, 10℃ / min, etc. In some embodiments, after heating to 300-400℃ in step (2), the temperature is held for 1-2 hours, such as 1 hour, 1.5 hours, 2 hours, etc. In some embodiments, after heating to 600-800℃ in step (2), the temperature is held for 0.5-4 hours, such as 0.5 hours, 1 hour, 2 hours, 3 hours, 4 hours, etc.

[0048] In some embodiments, in step (3), the concentration of the alkaline solution is 1-5 mol / L, such as 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, etc., preferably 2-3 mol / L; using an alkaline solution of the preferred concentration for heat treatment is beneficial to further reduce the ash content of the obtained adsorbent material and further improve the carbon dioxide adsorption performance.

[0049] Preferably, the alkaline solution is an aqueous solution of potassium hydroxide and / or sodium hydroxide, more preferably an aqueous solution of potassium hydroxide, which can form a substance similar to -COOK, thereby further enhancing the carbon dioxide adsorption effect.

[0050] In some implementations, the heat treatment time in step (3) is 0.5-6 hours, for example 0.5 hours, 1 hour, 2 hours, 4 hours, 6 hours, etc.

[0051] Preferably, the heat treatment temperature in step (3) is 70-80°C. Performing heat treatment at the preferred temperature is beneficial for obtaining carbon dioxide adsorbent materials with better performance.

[0052] Preferably, the ultrasonic frequency of the ultrasound in step (3) is 40-80 Hz, such as 40 Hz, 50 Hz, 70 Hz, 80 Hz, etc.

[0053] Preferably, the gas introduced during bubbling in step (3) is one or more of compressed air, nitrogen, and O2, and more preferably, the gas introduced during bubbling is O2. Using the preferred gas for bubbling heat treatment is beneficial to further reduce the ash content of the obtained adsorbent material, and at the same time, it is beneficial to obtain an adsorbent material with better carbon dioxide adsorption performance.

[0054] In some implementations, step (2) is carried out in a tubular furnace.

[0055] In some implementations, in step (1), the basic raw material is pre-crushed to below 200 mesh.

[0056] In this invention, the heat treatment in step (3) is performed under conditions of ultrasound and / or bubbling with gas. For example, a heating tube is arranged in a container with ultrasound for heat treatment, or a heating tube is arranged in a container with bubbling tubes for heat treatment, or a heating tube is arranged in a container with both ultrasound and bubbling tubes for heat treatment. See the schematic diagram below. Figure 2 In a preferred embodiment, the heat treatment is carried out under ultrasonic and gas-bubbling conditions. This preferred method of treating the material with "ultrasonic vibration-bubbling strengthening-alkali heat impregnation" is beneficial for obtaining a carbon dioxide adsorbent material with further reduced ash content and better adsorption performance.

[0057] The present invention also provides the application of the CO2 adsorbent material prepared by the preparation method described above in CO2 adsorption.

[0058] The present invention will be further illustrated by the following embodiments, but it is not intended that the present invention is limited to the following embodiments.

[0059] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in this technical field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0060] The test methods used in the following examples and comparative examples:

[0061] Adsorption capacity: The adsorption capacity of the sample was determined using a STA 449F3 synchronous thermal analyzer manufactured by Netzsch GmbH, Germany. The test conditions were as follows: the sample was pretreated in N2 at 300℃ for 30 min to remove any physically adsorbed impurities such as H2O and / or CO2. After the temperature was cooled and stabilized at 40℃, the sample was switched to the adsorption gas and the adsorption capacity was calculated based on the weight gain.

[0062] CO2 / N2 selectivity: The CO2 / N2 ratio of simulated flue gas (15 vol% CO2 / 85 vol% N2) was measured using a BSD-MAB multi-component competitive adsorption analyzer manufactured by Bestech. The sample was pretreated at 300℃ for 120 min, and the adsorption temperature was 40℃. The selectivity was calculated based on the adsorption breakthrough curve, using the following formula:

[0063] CO2 / N2 selectivity S = (X1 / Y1) / (X2 / Y2)

[0064] X1 / Y1 is the mole fraction of CO2 in the adsorbed phase / the mole fraction of CO2 in the gas phase;

[0065] X2 / Y2 is the mole fraction of N2 in the adsorbed phase / the mole fraction of N2 in the gas phase.

[0066] Ash content: determined in accordance with national standard GB / T30732.

[0067] The following describes some of the raw materials used in the examples and comparative examples:

[0068] Coal liquefaction residue: The ash content is 26.28%. Fe and S are both ash impurities. The content of ash in the form of Fe2O3 accounts for 53.48%, and the content in the form of SO3 accounts for 22.33%.

[0069] 15% CO2 simulated flue gas: The gas composition is 15% CO2 and 85% N2, by volume percentage.

[0070] Example 1

[0071] (1) Crush the coal liquefaction residue to a particle size of less than 200 mesh, mix the coal liquefaction residue (i.e. "basic raw material") and potassium hydroxide activator at a mass ratio of 1:1 and grind them evenly to obtain a mixture.

[0072] (2) Place the mixture in a tube furnace and heat it from room temperature to a first temperature of 300°C at a first heating rate of 5°C / min under a nitrogen atmosphere and hold it at that temperature for 1 hour (i.e., the first holding time). Then heat it to a second temperature of 700°C at a second heating rate of 5°C / min and hold it at that temperature for 2 hours (i.e., the second holding time) for carbonization activation.

[0073] (3) The carbonized and activated sample was subjected to "ultrasound + bubbling" heat treatment: The carbonized and activated sample was placed in a 2 mol / L potassium hydroxide aqueous solution and heat-treated under the conditions of ultrasonic frequency of 50 Hz and compressed air being introduced through the bubbling tube for bubbling, at a temperature of 70 ℃ and a treatment time of 2 hours.

[0074] The treated sample was washed with water and dried at 120℃ to obtain a high-performance CO2 adsorption material.

[0075] The final test results of the prepared CO2 adsorbent material show that the potassium (K) element is uniformly dispersed in the material (the distribution of K, Fe, and S elements is shown in [reference]). Figure 3 The presence of K can improve the surface activity of the material; at the same time, the content of Fe and S impurities is significantly reduced, the ash content of the material is only 0.48%, the CO2 adsorption capacity under simulated flue gas conditions of 40℃ and 15% CO2 is 7.59wt%, the CO2 / N2 selectivity reaches 32, the microporosity is over 99%, and it is mainly an ultramicroporous structure below 0.7nm.

[0076] Example 2 (no bubbling performed compared to Example 1)

[0077] (1) Crush the coal liquefaction residue to a particle size of less than 200 mesh, mix the coal liquefaction residue and potassium hydroxide activator at a mass ratio of 1:1 and grind them evenly to obtain a mixture.

[0078] (2) Place the mixture in a tube furnace and heat it from room temperature to 300°C at a rate of 5°C / min under a nitrogen atmosphere for 1 hour. Then heat it to 700°C at a rate of 5°C / min and hold it for 2 hours for carbonization activation.

[0079] (3) The carbonized and activated sample was subjected to ultrasonic heat treatment: The carbonized and activated sample was placed in a 2 mol / L potassium hydroxide aqueous solution and subjected to heat treatment at an ultrasonic frequency of 50 Hz, a temperature of 70 °C, and a treatment time of 2 hours.

[0080] The treated sample was washed with water and dried at 120℃ to obtain a high-performance CO2 adsorption material.

[0081] The final test results of the CO2 adsorption material showed that the ash content of the material was 1.08%, the CO2 adsorption capacity was 7.17wt% under the simulated flue gas conditions of 40℃ and 15% CO2, the CO2 / N2 selectivity reached 28, the microporosity was over 99%, and the main structure was an ultramicroporous structure of less than 0.7nm.

[0082] Example 3

[0083] The procedure is carried out in accordance with Example 1, except that ultrasound is not performed during heat treatment in step (3).

[0084] Experimental results: The test results of the finally prepared CO2 adsorption material showed that the ash content of the material was 1.13%, the CO2 adsorption capacity was 7.20wt% under the conditions of 40℃ and 15% CO2 simulated flue gas, the CO2 / N2 selectivity reached 29, the microporosity was over 99%, and the main structure was ultramicroporous structure below 0.7nm.

[0085] Example 4

[0086] The procedure was carried out in accordance with Example 1, except that the concentration of the potassium hydroxide aqueous solution in step (3) was 1 mol / L.

[0087] Experimental results: The test results of the final CO2 adsorption material showed that the ash content of the material was 0.79%, the CO2 adsorption capacity was 6.70 wt% under the conditions of 40℃ and 15% CO2 simulated flue gas, the CO2 / N2 selectivity reached 25, the microporosity was over 99%, and the main structure was an ultramicroporous structure below 0.7 nm.

[0088] Example 5

[0089] The procedure was carried out in accordance with Example 1, except that the concentration of the potassium hydroxide aqueous solution in step (3) was 5 mol / L.

[0090] Experimental results: The test results of the final CO2 adsorption material showed that the ash content of the material was 0.82%, the CO2 adsorption capacity was 6.55wt% under the conditions of 40℃ and 15% CO2 simulated flue gas, the CO2 / N2 selectivity reached 26, the microporosity was over 99%, and the main structure was an ultramicroporous structure below 0.7nm.

[0091] Example 6

[0092] The procedure was carried out in accordance with Example 1, except that the gas introduced into the bubbling tube in step (3) was O2.

[0093] Experimental results: The test results of the finally prepared CO2 adsorption material showed that the ash content of the material was 0.35%, the CO2 adsorption capacity was 7.84wt% under the conditions of 40℃ and 15% CO2 simulated flue gas, the CO2 / N2 selectivity reached 39, the microporosity was over 99%, and the main structure was ultramicroporous structure below 0.7nm.

[0094] Example 7

[0095] The procedure is carried out in accordance with Example 1, except that the process conditions for each step are shown in Table 1 below.

[0096] Experimental results: The test results of the final CO2 adsorption material showed that the ash content of the material was 0.95%, the CO2 adsorption capacity was 6.42wt% under the conditions of 40℃ and 15% CO2 simulated flue gas, the CO2 / N2 selectivity reached 31, the microporosity was over 96%, and the main structure was ultramicroporous structure below 0.7nm.

[0097] Example 8

[0098] The procedure is carried out in accordance with Example 1, except that the process conditions for each step are shown in Table 1 below.

[0099] Experimental results: The test results of the final CO2 adsorption material showed that the ash content of the material was 1.24%, the CO2 adsorption capacity was 6.37wt% under the conditions of 40℃ and 15% CO2 simulated flue gas, the CO2 / N2 selectivity reached 23, the microporosity was over 95%, and the main structure was ultramicroporous structure below 0.7nm.

[0100] Table 1 Experimental conditions for Examples 7 and 8

[0101]

[0102] Comparative Example 1

[0103] (1) Crush the coal liquefaction residue to a particle size of less than 200 mesh, mix the coal liquefaction residue and potassium hydroxide activator at a mass ratio of 1:1 and grind them evenly to obtain a mixture.

[0104] (2) Place the mixture in a tube furnace and heat it from room temperature to 300°C at a rate of 5°C / min under a nitrogen atmosphere for 1 hour. Then heat it to 700°C at a rate of 5°C / min and hold it for 2 hours for carbonization activation.

[0105] The carbonized and activated sample was then acid-washed (using a 5% dilute hydrochloric acid solution until no more bubbles appeared), washed with water, and dried to obtain the CO2 adsorption material. The distribution of K, Fe, and S elements in the obtained material is shown in the figure. Figure 3 It is evident that the potassium (K) content is low and unevenly distributed, mainly due to residual K that did not react during carbonization, activation, and acid washing. Simultaneously, it can be seen that the raw material contains a high amount of undecomposed Fe and S impurities, significantly higher than the impurity content in Example 1. Testing revealed that the material has an ash content of 2.21%, a CO2 adsorption capacity of 3.55 wt% under simulated flue gas conditions of 40℃ and 15% CO2, a CO2 / N2 selectivity of 15, and a microporosity exceeding 99%, primarily consisting of ultramicroporous structures below 0.7 nm.

[0106] Comparative Example 2

[0107] The procedure was carried out in accordance with Example 1, except that in step (3), the temperature condition for heat treatment was 45°C.

[0108] Experimental results: The test results of the final CO2 adsorption material showed that the ash content of the material was 1.88%, the CO2 adsorption capacity was 4.17wt% under the conditions of 40℃ and 15% CO2 simulated flue gas, the CO2 / N2 selectivity reached 19, the microporosity was over 99%, and the main structure was an ultramicroporous structure below 0.7nm.

[0109] Comparative Example 3

[0110] The process was carried out in accordance with Example 1, except that in step (2), the temperature was directly increased from room temperature to 900°C at a rate of 20°C / min and held at a constant temperature for 1 hour for carbonization activation.

[0111] Experimental results: The test results of the final CO2 adsorption material showed that the ash content of the material was 5.23%, the CO2 adsorption capacity was 3.09wt% under the simulated flue gas conditions of 40℃ and 15% CO2, the CO2 / N2 selectivity reached 12, and the microporosity was about 75%, mainly micro-mesoporous structure.

[0112] Table 1 summarizes the experimental results of ash content and adsorption performance for each embodiment and comparative example.

[0113]

[0114]

[0115] Note: If the data in Table 1 is inconsistent with the textual descriptions of the preceding embodiments and comparative examples, the textual descriptions of the preceding examples shall prevail.

[0116] The experimental results above show that, compared with the comparative example, the carbon dioxide adsorbent material prepared by the method of the present invention not only has a lower ash content, but also achieves a higher carbon dioxide adsorption capacity and CO2 / N2 selectivity.

[0117] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a CO2 adsorbent material, characterized in that, Includes the following steps: (1) The basic raw materials are mixed with an activator containing alkali metal elements and ground evenly to obtain a mixture; the basic raw materials are one or more of coal and coal-related products; (2) The mixture is first heated to 300-400℃ and kept at that temperature under a protective atmosphere or vacuum; then heated to 600-800℃ and kept at that temperature to obtain a carbonized and activated sample. (3) The carbonized and activated sample is placed in an aqueous solution or an alkaline solution containing alkali metal ions and heat-treated at 50-80°C, and the heat treatment is carried out under ultrasonic and / or gas bubbling conditions; then washed with water and dried to obtain the CO2 adsorbent material.

2. The method for preparing the CO2 adsorbent material according to claim 1, characterized in that, The coal-related products are selected from one or more of coal liquefaction residue and coal tar pitch. And / or, the activator is selected from one or more of potassium hydroxide, potassium carbonate, sodium hydroxide, and sodium carbonate.

3. The method for preparing the CO2 adsorbent material according to claims 1-2, characterized in that, The mass ratio of the basic raw material to the activator is 1:(0.5-4).

4. The method for preparing the CO2 adsorbent material according to any one of claims 1-3, characterized in that, In step (2), the protective atmosphere is nitrogen, argon and / or waste gas.

5. The method for preparing the CO2 adsorbent material according to any one of claims 1-4, characterized in that, In step (2), the heating rate to 300-400℃ is 1-10℃ / min; And / or, the heating rate to 600-800℃ is 1-10℃ / min; And / or, after heating to 300-400℃ in step (2), keep warm for 1-2 hours; And / or, after heating to 600-800℃ in step (2), keep warm for 0.5-4 hours.

6. The method for preparing the CO2 adsorbent material according to any one of claims 1-5, characterized in that, In step (3), the concentration of the alkaline solution is 1-5 mol / L, preferably 2-3 mol / L; Preferably, the alkaline solution is an aqueous solution of potassium hydroxide and / or sodium hydroxide.

7. The method for preparing the CO2 adsorbent material according to any one of claims 1-6, characterized in that, The heat treatment in step (3) takes 0.5-6 hours.

8. The method for preparing the CO2 adsorbent material according to any one of claims 1-7, characterized in that, The heat treatment temperature is 70-80℃; And / or, the ultrasonic frequency of the ultrasound is 40-80 Hz; And / or, the gas introduced through the bubbling is one or more of compressed air, nitrogen, and O2, preferably O2; And / or, step (2) is performed in a tubular furnace; And / or, in step (1), the basic raw material is pre-crushed to below 200 mesh.

9. The method for preparing the CO2 adsorbent material according to any one of claims 1-8, characterized in that, The heat treatment is performed under ultrasonic and gas-breathing conditions.

10. The application of the CO2 adsorbent material prepared by the preparation method according to any one of claims 1-9 in the adsorption of CO2.

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