Carbon dioxide adsorption material as well as preparation method and application thereof

Abstract

The invention discloses a carbon dioxide adsorption material and a preparation method and application thereof.The preparation method includes the steps that activated aluminum oxide and carbonate are mixed in water to obtain a precursor, the precursor is roasted under the protection of protective gas, and the carbon dioxide adsorption material is prepared through organic amine dipping modification under the heating condition; in the preparation process, activated aluminum oxide serves as a core carrier, amino is introduced into an aluminum oxide structure, the chemical reaction activity between the aluminum oxide and carbon dioxide can be greatly enhanced, and therefore the adsorption capacity is remarkably improved. Carbonate loading is the key for further optimizing the performance of the adsorption material, adsorption active sites can be increased, the stability and selectivity of the adsorption material can be effectively improved, and the material is endowed with efficient carbon dioxide adsorption performance and cycling stability through the synergistic effect of the three.

Description

Technical Field

[0001] The present invention relates to the field of gas adsorption technology, in particular to the capture of carbon dioxide, and specifically to a carbon dioxide adsorption material and a preparation method and application thereof. Background Art

[0002] In today's era, the rapid development of global industrialization and energy consumption has caused carbon dioxide emissions to continue to rise, which has become a key factor in triggering global climate change, and has brought many severe challenges to the ecological environment and human society, such as melting glaciers, abnormal climate, and damage to biodiversity. In addition, in a poorly ventilated environment, the accumulation of carbon dioxide exhaled by the human body may affect health. In particular, in order to ensure the life, health and safety of workers in confined spaces, it is a very important task to strictly control the concentration of carbon dioxide in confined spaces to stabilize within a safe range.

[0003] Currently, the most commonly used method for capturing CO 2 The main methods include absorption, adsorption, membrane separation, low-temperature separation and other methods. Among them, the advantages of solvent absorption are high efficiency and good reversibility, but its disadvantages are that it is corrosive to equipment and has environmental pollution problems. The main advantages of membrane separation are simple equipment, easy operation, low energy consumption, high efficiency and low investment, but the separation and recovery of CO 2 The effect is poor, the equipment investment cost is high, the membrane is prone to aging, the cost of the membrane required for separation is high, and the reliability of long-term operation needs to be further resolved. The low-temperature separation method uses the difference in relative volatility of different component gases to separate mixed gases at low temperatures, but it is difficult to be widely used due to the large equipment required, high energy consumption, low separation efficiency, and high cost. The adsorption method has become a very potential method due to its low energy consumption, mild operating conditions, stable performance, fast adsorption rate, recyclability, and easy automation of the adsorption process. Therefore, the adsorption method is considered to be a very effective method for capturing carbon dioxide.

[0004] Commonly used adsorption materials mainly include carbon-based materials, zeolite molecular sieves, diatomaceous earth, alumina materials, etc. Among them, carbon materials have become an excellent adsorption and separation material due to their rich microporous structure, high specific surface area, stable chemical properties, acid and alkali resistance, etc. However, in practice, these materials have insufficient adsorption effect and adsorption cycle stability for carbon dioxide. Summary of the invention

[0005] The object of the present invention is to overcome one or more deficiencies in the prior art and to provide an improved carbon dioxide adsorption material having both good carbon dioxide adsorption effect and adsorption cycle stability and a preparation method thereof.

[0006] The present invention also provides an application of the above carbon dioxide adsorption material in carbon dioxide capture, especially in capturing carbon dioxide in flue gas with high carbon dioxide concentration, to achieve excellent adsorption effect and cyclic stability.

[0007] In order to achieve the above object, a technical solution adopted by the present invention is:

[0008] A method for preparing a carbon dioxide adsorbent material, the method comprising:

[0009] The active alumina with a porous structure and carbonate are stirred and mixed in water, and separated to obtain a solid precursor;

[0010] calcining the solid precursor in a protective atmosphere to obtain an adsorption material intermediate;

[0011] The adsorbent intermediate and an organic amine containing a plurality of secondary amines and / or primary amines are mixed in an alcohol solvent under heating conditions to produce a carbon dioxide adsorbent.

[0012] According to some preferred aspects of the present invention, the mass ratio of the activated alumina to the carbonate is 1:0.6-1.0, further 1:0.7-0.95.

[0013] According to some preferred aspects of the present invention, the particle size of the activated alumina is 30 nm to 1.8 mm, and the specific surface area is 100-300 m 2 / g.

[0014] In some embodiments of the present invention, the carbonate is sodium carbonate (Na 2 CO 3 ) and / or potassium carbonate (K 2 CO 3 ).

[0015] According to some preferred aspects of the present invention, the stirring and mixing is controlled to be performed at 20-30° C. Further, the stirring and mixing is performed at a stirring speed of 500-1500 rpm. In some embodiments of the present invention, the stirring and mixing is performed by magnetic stirring.

[0016] According to some preferred aspects of the present invention, the implementation method of preparing the solid precursor includes: dissolving carbonate in water to prepare a carbonate aqueous solution, and then adding activated alumina with a porous structure to the carbonate aqueous solution, mixing under stirring conditions and at room temperature for 10-40 hours, filtering after completion, washing the filtrate with ethanol, and drying.

[0017] In some embodiments of the present invention, the molar concentration of the carbonate aqueous solution is 1-5 mol / L.

[0018] In some embodiments of the present invention, during the process of preparing the solid precursor, the drying is performed at 50-90° C., and further, the drying time can be 4-12 hours.

[0019] According to some preferred aspects of the present invention, the protective atmosphere is formed by introducing nitrogen and / or an inert gas. Further, the inert gas includes but is not limited to helium, argon, etc.

[0020] According to some preferred aspects of the present invention, the calcination temperature is controlled to be 200-400°C.

[0021] According to some preferred aspects of the present invention, the heating rate of the calcination is controlled to be 1-10°C / min, further 2-6°C / min.

[0022] According to some preferred aspects of the present invention, the calcination time is controlled to be 0.5-10 h, further 1-4 h.

[0023] According to some preferred aspects of the present invention, the feed mass ratio of the organic amine to the activated alumina is 0.1-0.7:1, further 0.2-0.6:1.

[0024] According to some preferred aspects of the present invention, the organic amine includes one or more selected from tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), polyethyleneimine (PEI).

[0025] In some embodiments of the present invention, the alcohol solvent includes ethanol.

[0026] According to some preferred aspects of the present invention, the heating conditions are controlled so that the mixing is performed at 60-80°C.

[0027] According to some preferred aspects of the present invention, the implementation method of preparing the carbon dioxide adsorption material includes: dispersing an organic amine in an alcohol solvent to prepare an organic amine alcohol solution, then immersing the adsorption material intermediate in the organic amine alcohol solvent, and refluxing for 0.5-4h under heating conditions, filtering after completion, washing the filtrate with ethanol, and drying.

[0028] Another technical solution provided by the present invention is a carbon dioxide adsorbent material prepared by the above-mentioned method for preparing the carbon dioxide adsorbent material.

[0029] Another technical solution provided by the present invention is: use of the above-mentioned carbon dioxide adsorption material in capturing carbon dioxide.

[0030] According to some specific and preferred aspects of the present invention, in the application, the flue gas is passed into a reactor filled with the carbon dioxide adsorbent material, and after adsorption, the flue gas is discharged;

[0031] Wherein, the volume content of the carbon dioxide in the flue gas is 0.1%-20%.

[0032] Furthermore, the flue gas contains, by volume percentage, 5%-20% carbon dioxide, 80%-95% nitrogen, and does not contain sulfur and / or nitrogen oxides.

[0033] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0034] Based on the defects of existing adsorption materials for capturing carbon dioxide, such as insufficient adsorption effect and adsorption cycle stability, the inventors of the present invention unexpectedly found in a large number of experimental studies that the modified activated alumina was modified with carbonate and organic amine in sequence, and calcined after carbonate modification, and then modified with organic amine, which achieved surprising results, specifically, the carbon dioxide adsorption amount and adsorption cycle stability were significantly improved; after further mechanism research, it was analyzed that: first, carbonate can react chemically with carbon dioxide, the loading of carbonate can effectively increase the adsorption active sites, and carbonate and alumina may have interacted with each other. Since carbonate is alkaline and alumina is an amphoteric compound, after the combination of the two, the alkalinity of alumina is further amplified, the expression of acidity is suppressed, and it is conducive to combining with acidic carbon dioxide, so that the overall material is not only more tightly combined, but also effectively improves the carbon dioxide adsorption selectivity and stability of the adsorbent material, and reduces the interference of other gases; secondly, when further combined with calcination treatment, it can not only effectively remove impurities, but also further release the active sites of the adsorbent material. point, and at the same time, the binding tightness between carbonate and alumina is strengthened, and the stability of the adsorbent material is improved; further, the present invention further combines with organic amine for modification, especially the organic amine containing multiple secondary amine and / or primary amine groups is modified under heating conditions. First, the introduction of amine groups into the alumina structure can change the surface properties of the adsorbent material, increase its affinity and selectivity for carbon dioxide, and greatly enhance the chemical reaction activity between it and carbon dioxide, thereby significantly improving the carbon dioxide adsorption capacity and carbon dioxide adsorption selectivity; second, under heating conditions, the organic amine can further fill the binding gap between carbonate and activated alumina, improve the adhesion stability of carbonate, and the organic amine contains more nitrogen atoms with lone pairs of electrons, which is easier to form a coordination bond with aluminum in alumina, thereby greatly improving the stability of the three combinations; third, the organic amine itself has a strong alkalinity, and can react chemically with acidic carbon dioxide molecules to form stable compounds such as carbamates (which can be desorbed at high temperature and then converted into organic amines), thereby significantly enhancing the adsorption capacity of the adsorbent material. The synergistic effect of the three gives the adsorbent material a high adsorption selectivity and high cycle stability for carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The CO of the carbon dioxide adsorbent material obtained in Examples 1 to 3 and Comparative Examples 1 to 5 of the present invention 2 penetration curve;

[0036] Figure 2 The CO of the carbon dioxide adsorbent material obtained in Examples 1 to 3 and Comparative Examples 1 to 5 of the present invention 2 Comparison chart of adsorption amount. DETAILED DESCRIPTION

[0037] The present invention aims to provide a carbon dioxide adsorption material having at least high adsorption selectivity and high cycle stability and a preparation method thereof.

[0038] The present invention obtains a precursor by mixing activated alumina with a carbonate solution, treating the precursor, and then preparing a carbon dioxide adsorbent material by roasting under protective gas protection and impregnating and modifying the precursor with an organic amine under heating conditions. In this preparation process, activated alumina is used as a core carrier to introduce amine groups into the alumina structure, which can greatly enhance the chemical reaction activity between the alumina and carbon dioxide, thereby significantly improving the adsorption capacity, so that carbon dioxide can be effectively captured in the form of carbamates and the like. The loading of carbonate is a key step in further optimizing the performance of the adsorbent material. It can not only increase the adsorption active sites, but also effectively improve the stability and selectivity of the adsorbent material, and reduce the interference of other gases. The synergistic effect of the three gives the material efficient carbon dioxide adsorption performance. Compared with traditional adsorbent materials, the preparation process of this material is simple and does not require complex auxiliary reagents. The obtained material has a strong adsorption affinity and selectivity for carbon dioxide, can efficiently capture carbon dioxide, and has remarkable characteristics such as excellent adsorption performance and strong stability. In terms of environmental protection, this material can be used in industrial waste gas treatment, carbon capture and storage, etc., effectively reducing the carbon dioxide content in the atmosphere, alleviating the greenhouse effect, and playing a positive role in global climate change response. It provides strong support for low-carbon and environmentally friendly technologies under the sustainable development strategy, and has broad market application prospects and important environmental strategic value.

[0039] Furthermore, the present invention provides a method for preparing a carbon dioxide adsorbent material, the method comprising: stirring and mixing activated alumina with a porous structure and carbonate in water, separating to obtain a solid precursor; calcining the solid precursor in a protective atmosphere to obtain an adsorbent material intermediate; mixing the adsorbent material intermediate and an organic amine containing multiple secondary amines and / or primary amines in an alcohol solvent under heating conditions to generate a carbon dioxide adsorbent material.

[0040] The above scheme is further described below in conjunction with specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions adopted in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0041] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0042] Activated alumina particles were purchased from Shanghai Titan Technology Co., Ltd., brand 016301581, with a particle size of about 30 nm and a specific surface area of ​​about 200 m 2 / g; PEI, polyethyleneimine, purchased from Shanghai Titan Technology Co., Ltd., brand 01123103, molecular weight about 600; activated carbon powder purchased from Shanghai Titan Technology Co., Ltd., brand 045697212, specific surface area about 3312m 2 / g.

[0043] Example 1

[0044] This example provides a method for preparing a carbon dioxide adsorbent material and the carbon dioxide adsorbent material prepared therefrom. The preparation method comprises:

[0045] Weigh 0.04 mol Na 2 CO 3 Dissolve in 15 mL of deionized water and stir to dissolve evenly;

[0046] Weigh 5.0g of activated alumina particles and add them to the above solution. The system is stirred and mixed at room temperature and 1200rpm. After fully mixing, continue stirring for 24 hours. After completion, filter with a Buchner funnel, wash with anhydrous ethanol, and then dry in a 60℃ drying oven for 6 hours. Then cool to room temperature, take out and seal for subsequent experiments.

[0047] The product obtained in the previous step was poured into a porcelain boat, flattened and transferred to a tube furnace in a nitrogen atmosphere, and heated from room temperature to 400°C at a heating rate of 4°C / min for 3 hours. Then it was cooled to room temperature to obtain an adsorption material intermediate.

[0048] Finally, the organic amine was loaded onto the adsorption material intermediate prepared according to the previous method by impregnation. 2.0g PEI was dissolved in 20mL ethanol, stirred evenly, and 10g of fully dried adsorption material intermediate prepared according to the previous method was added, and heated to reflux at 60°C for 2 hours. After completion, it was filtered with a Buchner funnel, washed with anhydrous ethanol, and then dried in a 60°C drying oven for 6 hours, and then cooled to room temperature to obtain a carbon dioxide adsorption material.

[0049] Example 2

[0050] This example provides a method for preparing a carbon dioxide adsorbent material and the carbon dioxide adsorbent material prepared therefrom. The preparation method comprises:

[0051] Weigh 0.04 mol K 2 CO 3 Dissolve in 15 mL of deionized water and stir to dissolve evenly;

[0052] Weigh 5.0g of activated alumina particles and add them to the above solution. The system is stirred and mixed at room temperature and 1200rpm. After fully mixing, continue stirring for 24 hours. After completion, filter with a Buchner funnel, wash with anhydrous ethanol, and then dry in a 60℃ drying oven for 6 hours. Then cool to room temperature, take out and seal for subsequent experiments.

[0053] The product obtained in the previous step was poured into a porcelain boat, flattened and transferred to a tube furnace in a nitrogen atmosphere, and heated from room temperature to 400°C at a heating rate of 4°C / min for 3 hours. Then it was cooled to room temperature to obtain an adsorption material intermediate.

[0054] Finally, the organic amine was loaded onto the adsorption material intermediate prepared according to the previous method by impregnation. 2.0g PEI was dissolved in 20mL ethanol, stirred evenly, and 10g of fully dried adsorption material intermediate prepared according to the previous method was added, and heated to reflux at 60°C for 2 hours. After completion, it was filtered with a Buchner funnel, washed with anhydrous ethanol, and then dried in a 60°C drying oven for 6 hours, and then cooled to room temperature to obtain a carbon dioxide adsorption material.

[0055] Example 3

[0056] This example provides a method for preparing a carbon dioxide adsorbent material and the carbon dioxide adsorbent material prepared therefrom. The preparation method comprises:

[0057] Weigh 0.04 mol Na 2 CO 3 Dissolve in 15 mL of deionized water and stir to dissolve evenly;

[0058] Weigh 5.0g of activated alumina particles and add them to the above solution. The system is stirred and mixed at room temperature and 1200rpm. After fully mixing, continue stirring for 24 hours. After completion, filter with a Buchner funnel, wash with anhydrous ethanol, and then dry in a 60℃ drying oven for 6 hours. Then cool to room temperature, take out and seal for subsequent experiments.

[0059] The product obtained in the previous step was poured into a porcelain boat, flattened and transferred to a tube furnace in a nitrogen atmosphere, and heated from room temperature to 400°C at a heating rate of 4°C / min for 3 hours. Then it was cooled to room temperature to obtain an adsorption material intermediate.

[0060] Finally, the organic amine was loaded onto the adsorption material intermediate prepared according to the previous method by impregnation. 2.0g TEPA was dissolved in 20mL ethanol, stirred evenly, and 10g of fully dried adsorption material intermediate prepared according to the previous method was added, and heated to reflux at 60°C for 2 hours. After completion, it was filtered with a Buchner funnel, washed with anhydrous ethanol, and then dried in a 60°C drying oven for 6 hours, and then cooled to room temperature to obtain a carbon dioxide adsorption material.

[0061] Comparative Example 1

[0062] This example provides a method for preparing a carbon dioxide adsorbent material and the carbon dioxide adsorbent material prepared therefrom. The preparation method comprises:

[0063] 2.0 g PEI was dissolved in 20 mL ethanol, stirred evenly, and then 10 g fully dried activated alumina particles were added, and heated under reflux at 60 ° C for 2 hours. After completion, the mixture was filtered with a Buchner funnel, washed with anhydrous ethanol, and then dried in a drying oven at 60 ° C for 6 hours, and then cooled to room temperature to obtain the corresponding carbon dioxide adsorption material.

[0064] Comparative Example 2

[0065] This example provides a method for preparing a carbon dioxide adsorbent material and the carbon dioxide adsorbent material prepared therefrom. The preparation method comprises:

[0066] Dissolve 2.0 g PEI in 20 mL ethanol, stir evenly, and add 10 g fully dried Na 2 CO 3 The material was heated to reflux at 60°C for 2 hours. After the reaction, it was filtered with a Buchner funnel, washed with anhydrous ethanol, and then dried in a drying oven at 60°C for 6 hours, and then cooled to room temperature to obtain the corresponding carbon dioxide adsorption material.

[0067] Comparative Example 3

[0068] This example provides a method for preparing a carbon dioxide adsorbent material and the carbon dioxide adsorbent material prepared therefrom. The preparation method comprises:

[0069] Weigh 0.04 mol Na 2 CO 3 Dissolve in 15 mL of deionized water and stir to dissolve evenly;

[0070] Weigh 5.0g of activated alumina particles and add them to the above solution. The system is stirred and mixed at room temperature and 1200rpm. After fully mixing, continue stirring for 24 hours. After completion, filter with a Buchner funnel, wash with anhydrous ethanol, and then dry in a 60℃ drying oven for 6 hours. Then cool to room temperature, take out and seal for subsequent experiments.

[0071] Pour the product obtained in the previous step into a porcelain boat, flatten it and transfer it to a tubular furnace in a nitrogen atmosphere. Heat the temperature from room temperature to 400°C at a heating rate of 4°C / min, heat at a constant temperature for 3 hours, and then cool it to room temperature to obtain the corresponding carbon dioxide adsorption material.

[0072] Comparative Example 4

[0073] This example provides a method for preparing a carbon dioxide adsorbent material and the carbon dioxide adsorbent material prepared therefrom. The preparation method comprises:

[0074] Weigh 0.04 mol Na 2 CO 3 Dissolve in 15 mL of deionized water and stir to dissolve evenly;

[0075] Weigh 5.0g of activated carbon powder and add it to the above solution. The system is stirred and mixed at room temperature and 1200rpm. After fully mixing, continue stirring for 24 hours. After completion, filter with a Buchner funnel, wash with anhydrous ethanol, and then dry in a 60℃ drying oven for 6 hours. Then cool to room temperature, take out and seal for subsequent experiments.

[0076] Pour the product obtained in the previous step into a porcelain boat, flatten it and transfer it to a tube furnace in a nitrogen atmosphere. Heat the temperature from room temperature to 400°C at a heating rate of 4°C / min, heat at a constant temperature for 3 hours, and then cool it to room temperature to obtain an adsorption material intermediate.

[0077] Finally, the organic amine was loaded onto the adsorption material intermediate prepared according to the previous method by impregnation. 2.0g PEI was dissolved in 20mL ethanol, stirred evenly, and 10g of fully dried adsorption material intermediate prepared according to the previous method was added, and heated to reflux at 60°C for 2 hours. After completion, it was filtered with a Buchner funnel, washed with anhydrous ethanol, and then dried in a 60°C drying oven for 6 hours, and then cooled to room temperature to obtain the corresponding carbon dioxide adsorption material.

[0078] Comparative Example 5

[0079] This example provides a method for preparing a carbon dioxide adsorbent material and the carbon dioxide adsorbent material prepared therefrom. The preparation method comprises:

[0080] Weigh 0.04 mol Na 2 CO 3 Dissolve in 15 mL of deionized water and stir to dissolve evenly;

[0081] Weigh 5.0g of activated alumina particles and add them to the above solution. The system is stirred and mixed at room temperature and 1200rpm. After fully mixing, continue stirring for 24 hours. After completion, filter with a Buchner funnel, wash with anhydrous ethanol, and then dry in a 60℃ drying oven for 6 hours. Then cool to room temperature, take out and seal for subsequent experiments.

[0082] Pour the product obtained in the previous step into a porcelain boat, flatten it and transfer it to a tube furnace in a nitrogen atmosphere. Heat the temperature from room temperature to 400°C at a heating rate of 4°C / min, heat at a constant temperature for 3 hours, and then cool it to room temperature to obtain an adsorption material intermediate.

[0083] Finally, potassium hydroxide was loaded onto the adsorption material intermediate prepared according to the previous step by impregnation. 2.0 g of potassium hydroxide was dissolved in 20 mL of ethanol, stirred evenly, and added to 10 g of fully dried adsorption material intermediate prepared according to the previous step, and heated under reflux at 60 ° C for 2 hours. After completion, it was filtered with a Buchner funnel, washed with anhydrous ethanol, and then dried in a 60 ° C drying oven for 6 hours, and then cooled to room temperature to obtain a carbon dioxide adsorption material.

[0084] Performance Testing

[0085] The adsorbent material was placed in a fixed bed adsorption device for carbon dioxide adsorption and desorption performance testing. The fixed bed reactor is a high temperature resistant glass tube with an inner diameter of 5 mm, an outer diameter of 10 mm, and a length of 200 mm, and a precision temperature control device is configured on the outside. The temperature deviation is less than ±0.5°C, and ultra-fine glass wool is filled at both ends of the fixed bed reactor to reduce the loss of the adsorbent material during the test.

[0086] 1.0 g of the carbon dioxide adsorbent obtained in Examples 1 to 3 and Comparative Examples 1 to 5 was uniformly filled into each fixed bed reactor. First, the adsorbent was heated at 100 mL min -1 High purity N 2 The reactor was heated at 373K for 1 hour under the atmosphere to remove impurities in the adsorbent. After the reactor was cooled to the required experimental temperature (333K) and stabilized, the gas line was switched to 100 mL min -1 Contains 15% CO 2 The simulated flue gas with a content of 2.5 g (the rest is nitrogen) was used for CO 2 Adsorption experiment. CO at the outlet of the fixed bed reactor 2 The concentration of CO 2 The analyzer measured that when the outlet CO 2 When the concentration is equal to the inlet concentration, it proves that the adsorption is saturated. 2 The concentration changes are used to draw the penetration curve. 2The CO can be obtained by integrating the area of ​​the penetration curve based on the inlet air concentration, flow rate and other conditions. 2 The adsorption amount and integral calculation formula are as follows:

[0087]

[0088] Where Q is the CO of the adsorbent material. 2 Adsorption capacity (mmol·g -1 ), m is the mass of the adsorbent material (g), v is the inlet gas flow rate (mL min -1 ), C 0 is the CO at the inlet of the fixed bed reactor 2 Concentration (vol.%), C is the CO concentration at the outlet of the fixed bed reactor 2 concentration (vol.%), t is the adsorption time (s), P is the experimental operating pressure (100 kPa), T is the experimental temperature (K), R is the gas constant (8.314 J·mol -1 ·K -1 ).

[0089] After the adsorption was completed, the gas flow was switched to 100 mL min -1 N 2 , and the temperature was raised to 373K for desorption experiments. When the fixed bed outlet CO 2 The gas concentration is 0, indicating that the adsorbent has been regenerated. 2 Adsorption / desorption experiments were performed to investigate the cyclic stability of the adsorbent.

[0090] (1) CO2 adsorption materials obtained in Examples 1 to 3 and Comparative Examples 1 to 5 2 See the penetration curve Figure 1 As shown, the CO of the carbon dioxide adsorbent materials obtained in Examples 1 to 3 and Comparative Examples 1 to 5 2 Adsorption capacity Figure 2 As shown,

[0091] Depend on Figure 1 It can be seen that the embodiments 1-3 of the present invention can reach the adsorption saturation state in a longer time than the comparative examples 1-5. Figure 2 The CO of each case is given. 2 Adsorption capacity; the results show that the present invention has a higher carbon dioxide adsorption capacity.

[0092] (2) The cyclic stability test data of different adsorption materials are shown in Table 1.

[0093] Table 1

[0094]

[0095]

[0096] Note: CO after 10 cycles 2 Adsorption capacity decrease percentage = (cycle 1 CO 2 Adsorption capacity - 10 cycles of CO 2 Adsorption capacity / cycle 1 time CO 2 Adsorption amount × 100%.

[0097] As can be seen from Table 1, the comparison between Comparative Example 1 and Example 1 shows that in the absence of carbonate, the carbon dioxide adsorption effect of the obtained material is greatly reduced;

[0098] The analysis shows that: First, carbonates can react chemically with carbon dioxide to form relatively stable substances such as bicarbonate, which can significantly improve the adsorption selectivity. Secondly, the presence of carbonates can change the surface properties and pore structure of the adsorption material. It can adjust the pH of the material to make it more conducive to the adsorption and activation of carbon dioxide molecules, while optimizing the pore structure to promote the diffusion and adsorption of carbon dioxide. It can be seen that in the system of the present invention, the lack of carbonates, these properties of the material cannot be optimized, and it is difficult for carbon dioxide molecules to fully contact the adsorption sites, resulting in a significant deterioration in the adsorption effect, which is difficult to meet the actual demand for efficient adsorption of carbon dioxide.

[0099] The comparison between Comparative Example 2 and Example 1 shows that when the adsorbent is not supported by an alumina substrate, the carbon dioxide adsorption effect also decreases, but the main manifestation is that the stability becomes very poor;

[0100] The analysis shows that the alumina substrate plays a key structural support role in the adsorption material. When there is no alumina substrate support, the amine-modified carbonate active component is difficult to maintain a stable dispersion state. During the adsorption process, due to the lack of anchoring and fixation of the substrate, the active components are prone to agglomeration, which reduces the effective active sites that can be used to adsorb carbon dioxide, resulting in a decrease in the adsorption effect.

[0101] The comparison between Comparative Example 3 and Example 1 mainly reflects the importance of organic amines in the adsorption of carbon dioxide in the adsorption material of the present invention. When amine modification is not performed, the adsorption capacity of alumina-supported carbonate itself for carbon dioxide is limited, resulting in a significant decrease in the adsorption effect, and the amount of carbon dioxide adsorbed is only about half of that in Example 1;

[0102] The analysis shows that: on the one hand, the amine group has a strong alkalinity and can react chemically with the acidic carbon dioxide molecules to form stable compounds such as carbamates, thereby achieving efficient adsorption. The lack of amine modification means the loss of this specific efficient adsorption reaction path, which greatly reduces the adsorption capacity. On the other hand, the amine group can change the surface properties of the adsorbent material, increase its affinity and selectivity for carbon dioxide, and the surface properties of the unmodified material are not conducive to the preferential adsorption and enrichment of carbon dioxide, making it difficult to effectively capture carbon dioxide in a complex gas environment. In addition, amine modification may also affect the pore structure and pore size distribution of the material. When unmodified, the pore structure is not conducive to the diffusion and adsorption of carbon dioxide molecules, which in turn causes the adsorption effect of the entire adsorbent material to become very poor and unable to meet the needs of actual applications.

[0103] The comparison between Comparative Example 4 and Example 1 shows that when the activated alumina substrate is replaced with activated carbon, the carbon dioxide adsorption effect also decreases;

[0104] The analysis shows that: although both activated alumina and activated carbon have certain adsorption capabilities, there are differences in their physical and chemical properties. The active sites on the surface of activated alumina can interact strongly with carbon dioxide molecules, thereby achieving efficient adsorption. Compared with activated alumina, the types and numbers of chemical functional groups on the surface of activated carbon have relatively weaker affinity for carbon dioxide and poorer selectivity. When the activated alumina substrate is replaced with activated carbon, the combined effect of these factors leads to a decrease in the carbon dioxide adsorption effect, and the good adsorption performance exhibited by the activated alumina substrate cannot be achieved. At the same time, the adsorption cycle stability also decreases significantly, indicating that the three materials of the present invention have better binding stability.

[0105] Comparison of Comparative Example 5 with Example 1 shows that when the organic amine active component is replaced with inorganic base potassium hydroxide, the carbon dioxide adsorption effect becomes worse;

[0106] The analysis shows that: from the perspective of adsorption mechanism, organic amines can form relatively stable chemical bonds with carbon dioxide molecules. This chemical adsorption is highly selective and can accurately adsorb carbon dioxide. The reaction of potassium hydroxide with carbon dioxide is mainly acid-base neutralization. The lack of this specific adsorption capacity reduces the adsorption selectivity of carbon dioxide. Secondly, organic amines can form high-density and stable active adsorption sites on the surface of the material through structural optimization. These sites can maintain good adsorption performance over a wide range of temperature and pressure, thereby ensuring a higher carbon dioxide adsorption capacity. Potassium hydroxide should be due to the limitations of its own chemical properties. The number and stability of its adsorption sites are not as good as those of organic amines. It is difficult to maintain efficient carbon dioxide adsorption, and the adsorption effect decreases. Moreover, after multiple cycles, the adsorption cycle stability has also decreased significantly.

[0107] In summary, the carbon dioxide adsorbent material of the present invention has the advantages of high adsorption capacity, high desorption performance and excellent cycle stability, and a synergistic effect is achieved between carbonate, activated alumina and organic amine.

[0108] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0109] The endpoints and any values ​​of the ranges disclosed in this article 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 endpoint values ​​of each range, the endpoint values ​​of each range and 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 as specifically disclosed in this article.

Claims

1. A method for preparing a carbon dioxide adsorbent material, characterized in that: The preparation method comprises: The active alumina with a porous structure and carbonate are stirred and mixed in water, and separated to obtain a solid precursor; calcining the solid precursor in a protective atmosphere to obtain an adsorption material intermediate; The adsorbent intermediate and an organic amine containing a plurality of secondary amines and / or primary amines are mixed in an alcohol solvent under heating conditions to produce a carbon dioxide adsorbent.

2. The method for preparing a carbon dioxide adsorbent material according to claim 1, characterized in that: The mass ratio of the activated alumina to the carbonate is 1:0.6-1.0, further 1:0.7-0.95; and / or the particle size of the activated alumina is 30nm to 1.8mm, and the specific surface area is 100-300m 2 / g; and / or, the carbonate is sodium carbonate and / or potassium carbonate.

3. The method for preparing a carbon dioxide adsorbent material according to claim 1, characterized in that: The stirring and mixing is controlled to be carried out at 20-30°C; and / or, an implementation method for preparing the solid precursor includes: dissolving carbonate in water to prepare a carbonate aqueous solution, and then adding activated alumina with a porous structure to the carbonate aqueous solution, mixing under stirring conditions and at room temperature for 10-40 hours, filtering after completion, washing the filtrate with ethanol, and drying.

4. The method for preparing a carbon dioxide adsorbent material according to claim 1, characterized in that: The protective atmosphere is formed by introducing nitrogen and / or an inert gas; and / or the calcination temperature is controlled to be 200-400°C; and / or the calcination heating rate is controlled to be 1-10°C / min, further to be 2-6°C / min; and / or the calcination time is controlled to be 0.5-10h, further to be 1-4h.

5. The method for preparing a carbon dioxide adsorbent material according to claim 1, characterized in that: The feed mass ratio of the organic amine to the activated alumina is 0.1-0.7:1, further 0.2-0.6:1; and / or the organic amine comprises a combination of one or more selected from tetraethylenepentamine, pentaethylenehexamine, and polyethyleneimine; and / or the alcohol solvent comprises ethanol.

6. The method for preparing a carbon dioxide adsorbent material according to claim 1, characterized in that: The heating conditions are controlled so that the mixing is carried out at 60-80°C; and / or, an implementation method for preparing the carbon dioxide adsorbent material includes: dispersing an organic amine in an alcohol solvent to prepare an organic amine alcohol solution, then immersing the adsorbent material intermediate in the organic amine alcohol solvent, and refluxing for 0.5-4h under heating conditions, filtering after completion, washing the filtrate with ethanol, and drying.

7. A carbon dioxide adsorbent material prepared by the method for preparing a carbon dioxide adsorbent material according to any one of claims 1 to 6.

8. Use of the carbon dioxide adsorbent material according to claim 7 in capturing carbon dioxide.

9. The use according to claim 8, characterized in that: In the application, the flue gas is passed into a reactor filled with the carbon dioxide adsorbent material, and after being adsorbed, the flue gas is discharged; Wherein, the volume content of the carbon dioxide in the flue gas is 0.1%-20%.

10. The use according to claim 9, characterized in that: Measured in volume percentage, the flue gas contains: 5%-20% carbon dioxide, 80%-95% nitrogen, and does not contain sulfur and / or nitrogen oxides.

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