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

Abstract

The invention discloses a carbon dioxide adsorption material as well as a preparation method and application thereof. The raw materials of the carbon dioxide adsorption material comprise a double-metal hydroxide loaded organic acid sodium material, the bimetal hydroxide loaded organic acid sodium material comprises layered bimetal hydroxide and organic acid sodium which is at least dispersed in a molecular level and is loaded on the bimetal hydroxide; the carbon dioxide adsorption material comprises a bimetallic oxide loaded sodium carbonate material, and the bimetallic oxide loaded sodium carbonate material is generated by performing chemical conversion treatment on raw materials; during preparation, an organic acid sodium solution is adopted as an active precursor, a load intermediate is formed by utilizing the directional anchoring effect of the active precursor and a layered structure of the double-metal hydroxide, then single-step temperature control calcination is performed, and carrier conversion and active component in-situ generation are synchronously completed; the carbon dioxide adsorption material disclosed by the invention shows high CO2 adsorption capacity and outstanding cycling stability in industrial flue gas, and is suitable for efficient capture and resource utilization of CO2 in flue gas in a high-emission industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas adsorption, in particular to a gas adsorption material, and more particularly to a carbon dioxide adsorption material, a preparation method and application thereof. BACKGROUND

[0002] Carbon capture and storage (CCUS) technology has become an irreplaceable key path for industrial deep decarbonization. With the continuous strengthening of emission reduction policies in various countries, CCUS technology is accelerating from the demonstration stage to large-scale commercial application. However, the current technical system still has significant bottlenecks: although the mainstream amine liquid absorption method is relatively mature, its high regeneration energy consumption (usually more than 3.5 GJ / t CO2) and serious equipment corrosion problems lead to high operating costs; emerging solid adsorption materials such as metal organic frameworks (MOFs) or functionalized zeolite molecular sieves, although they exhibit excellent adsorption selectivity, their complex synthesis process, high raw material cost and structural instability under hydrothermal conditions seriously restrict their widespread application in large industrial scenarios.

[0003] Sodium carbonate (Na2CO3) has long been considered as a potential alternative adsorbent due to its low cost, non-toxicity and considerable theoretical adsorption capacity. However, its intrinsic kinetic inertia and tendency to sinter and agglomerate during repeated adsorption-desorption cycles result in actual performance far below theoretical expectations. Currently, researchers generally use the strategy of carrier loading to improve the above defects. However, traditional loading techniques such as impregnation-melting or physical mixing, although simple in process, often result in sodium carbonate being physically attached to the surface of the carrier or clogging the pores in the form of micron-sized particles, making it difficult to fully utilize the overall theoretical adsorption capacity and limiting the utilization rate of active sites. Moreover, it is still difficult to avoid the migration and agglomeration of active components during high-temperature regeneration, leading to rapid degradation of adsorption performance.

[0004] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore the background section of the present application can contain background information about the problems or environment of the present application, and does not necessarily describe the prior art. Therefore, the content contained in the background section is not an admission by the applicant of prior art. SUMMARY

[0005] The purpose of the present application is to overcome one or more deficiencies in the prior art and provide an improved carbon dioxide adsorption material and a preparation method thereof.

[0006] The carbon dioxide adsorption material of the present application overcomes some defects of existing sodium carbonate in use when sodium carbonate is used as the main active component. The present application can achieve high adsorption capacity and long cycle stability.

[0007] The application also provides application of the carbon dioxide adsorption material in a carbon dioxide adsorption device.

[0008] To achieve the above object, the application adopts a technical solution of: The carbon dioxide adsorption material comprises a double-metal hydroxide loaded sodium organic acid material, wherein the double-metal hydroxide loaded sodium organic acid material comprises a layered double-metal hydroxide and sodium organic acid dispersed at a molecular level and loaded on the double-metal hydroxide. The carbon dioxide adsorption material comprises a double-metal oxide loaded sodium carbonate material, and the raw material is subjected to a chemical conversion treatment to generate the double-metal oxide loaded sodium carbonate material.

[0009] In some embodiments of the application, the chemical conversion treatment comprises a calcination treatment.

[0010] Further, the calcination temperature of the calcination treatment is 450-600℃.

[0011] In some embodiments of the application, in the double-metal oxide loaded sodium carbonate material, the sodium carbonate exists in the form of nanoparticles with an average particle size of 10-100nm, and the average particle size can be 10-90nm, 20-80nm, 30-60nm, etc.

[0012] In some embodiments of the application, the double-metal oxide loaded sodium carbonate material forms an open and interconnected pore network structure, which provides a good channel for gas diffusion.

[0013] In some embodiments of the application, the specific surface area of the double-metal oxide loaded sodium carbonate material is greater than or equal to 150m 2 / g, and further 150-200m 2 / g.

[0014] The application further provides another technical solution: a preparation method of a carbon dioxide adsorption material, which comprises the following steps: adding a layered double-metal hydroxide into a sodium organic acid solution, stirring and dispersing, separating, to obtain a double-metal hydroxide loaded sodium organic acid material, and then performing a calcination treatment under a protective atmosphere.

[0015] In some embodiments of the application, the mass ratio of the double-metal hydroxide to the sodium organic acid is controlled to be 1:1-3, for example, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc.

[0016] In some embodiments of the present application, the mass concentration of the sodium organic acid solution is 0.05-0.25 g / mL, for example, it can be 0.05 g / mL, 0.1 g / mL, 0.15 g / mL, 0.2 g / mL, 0.22 g / mL, 0.25 g / mL, etc.

[0017] In some embodiments of the present application, the sodium organic acid solution is prepared by dispersing sodium organic acid in water.

[0018] In some embodiments of the present application, the sodium organic acid comprises a combination of one or more selected from sodium citrate, sodium malate, sodium acetate.

[0019] In some embodiments of the present application, the double metal hydroxide is nickel-iron hydroxide.

[0020] In some embodiments of the present application, the roasting temperature of the roasting process is controlled to be 450-600 ℃, for example, it can be 450 ℃, 480 ℃, 500 ℃, 520 ℃, 550 ℃, 580 ℃, 600 ℃, etc.

[0021] In some embodiments of the present application, the roasting time of the roasting process is controlled to be 2-6 hours.

[0022] In some embodiments of the present application, the heating rate of the roasting process is controlled to be 4-8 ℃ / min.

[0023] In some embodiments of the present application, the protective atmosphere is formed by introducing nitrogen and / or inert gas. Further, the inert gas can be helium, argon, etc.

[0024] In some embodiments of the present application, the layered double metal hydroxide is prepared by the following method: The nickel salt and the iron salt are dispersed in water and mixed uniformly to obtain a nickel-iron solution, then a sodium carbonate aqueous solution with a volume difference of less than 5% from the nickel-iron solution is added, sodium hydroxide or its aqueous solution is used to adjust the pH value of the system to 9.5-10.5, and the layered double metal hydroxide is generated under stirring with heating.

[0025] In some embodiments of the present application, the nickel salt is a combination of one or more selected from nickel sulfate, nickel chloride, nickel nitrate, nickel acetate.

[0026] In some embodiments of the present application, the iron salt is a combination of one or more selected from ferric chloride, ferric sulfate, ferric nitrate.

[0027] In some embodiments of the present application, the mass ratio of the nickel salt to the iron salt is 1-4:1.

[0028] In some embodiments of the present application, the total concentration of nickel salt and iron salt in the nickel-iron solution is 0.5-1 mol / L.

[0029] In some embodiments of the present application, the concentration of the aqueous sodium carbonate solution is 0.5-1 mol / L.

[0030] In some embodiments of the present application, the volume of the nickel-iron solution and the volume of the added aqueous sodium carbonate solution differ by less than 2%, and further, the volumes are equal.

[0031] In some embodiments of the present application, when the aqueous sodium hydroxide solution is used to adjust the pH of the system, the concentration of the aqueous sodium hydroxide solution is 2-4 mol / L.

[0032] In some embodiments of the present application, the heating conditions are controlled such that the stirring is carried out at a temperature of 40-80℃, and further, the stirring time is controlled to be 8-12 hours.

[0033] In some embodiments of the present application, after the stirring and reaction are completed, water is used to wash to neutral, and anhydrous ethanol is used to wash multiple times, and the double-metal hydroxide is obtained by drying.

[0034] Further, the drying temperature can be 60-80℃, and the drying time can be 4-8 hours.

[0035] The present application further provides another technical solution: the above-mentioned carbon dioxide adsorption material or the carbon dioxide adsorption material prepared by the above-mentioned preparation method is applied in a carbon dioxide adsorption equipment.

[0036] Due to the use of the above technical solution, the present application has the following advantages compared with the prior art: Based on the defects of the existing sodium carbonate in the application process, the inventors of the present application have unexpectedly found, based on a large number of experimental researches, that when the layered double-metal hydroxide is used as a matrix precursor, the sodium organic acid is used as an active precursor, the two are mixed to form a loading relationship, and then calcined, the obtained double-metal oxide loaded sodium carbonate material as a carbon dioxide adsorption material not only has excellent adsorption capacity, but also maintains excellent cycle stability in long-term adsorption-desorption cycles, and better improves or solves the defects of the existing sodium carbonate in the application process. Through further mechanism research, the inventors believe that this may be due to the directional bonding between the organic acid ion in the sodium organic acid and the layer charge and surface hydroxyl of the layered double metal hydroxide, such as the coordination between the oxygen in the organic acid ion and the nickel ion and iron ion on the double metal hydroxide, or the strong hydrogen bond between the oxygen and the surface hydroxyl of the layer, so that the molecular level dispersion and anchoring of the organic acid ion in the interlayer and the inner wall of the pore of the substrate are more stable, and the loss or agglomeration of the organic acid ion in the subsequent treatment is reduced. Subsequently, single-step temperature-controlled calcination is performed to simultaneously complete the structure solidification of the carrier to the double metal oxide and the in-situ conversion of the sodium organic acid to the nanocrystalline sodium carbonate. In this calcination and conversion stage, the Ni-O and Fe-O active sites generated on the surface of the double metal oxide skeleton may form a weak electrostatic interaction with the Na + The weak electrostatic interaction, which may exist as the interface bonding force, can further inhibit the growth and migration of the nanoscale sodium carbonate particles, and avoid the problem of agglomeration of the active components in the traditional process. Meanwhile, the combination mode of the present application not only breaks through the limitations of uneven distribution of the active components in the traditional impregnation method and the weakening of the interface in the step-by-step calcination, but also combines the coordination, hydrogen bond and electrostatic interaction through the “layered precursor loading-cooperative conversion” mechanism, so that the in-situ generated sodium carbonate is more uniformly and stably dispersed in the high-stability carrier skeleton, and a more closely combined interface (instead of simple physical adhesion) is formed. The obtained material has a hierarchical pore structure (the specific surface area is above 150 m 2 / g) and high mechanical strength. It is believed that the excellent pore structure and the interface interaction between the double metal oxide and the sodium carbonate are related, and the plugging of the active components to the pore is reduced. Practice shows that the carbon dioxide adsorption material of the present application exhibits excellent CO2 adsorption kinetics in the industrial flue gas environment of 40-80°C, and due to the intrinsic stability of inorganic sodium carbonate and the possible interface bonding, the loss of the active components in the recycling process is reduced, so that the capacity retention rate of the material is above 86% after 10 adsorption-desorption cycles. The technology is suitable for flue gas purification systems in high-emission industries such as steel and cement, and provides a low-cost and high-adaptability solution for efficient capture and rapid desorption of low-concentration CO2, which significantly promotes the industrialization application process of carbon emission reduction technology. BRIEF DESCRIPTION OF DRAWINGS

[0037] Fig. 1 A scanning electron microscope (SEM) image (scale of 500 nm) of the carbon dioxide adsorption material prepared in Example 1 of the present application; Fig. 2 A scanning electron microscope (SEM) image (scale of 250 nm) of the carbon dioxide adsorption material prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0038] The application provides a bimetallic carrier in-situ loaded sodium carbonate carbon dioxide adsorption material and a preparation method thereof, and is realized by the following mode: Firstly, the nickel-iron bimetallic salt is dissolved in deionized water, a stable solution is formed through homogenizing stirring, a sodium carbonate solution is added and the pH is adjusted to an alkaline environment, and a layered double hydroxide precursor is constructed through a hydrothermal reaction; Secondly, the organic acid sodium solution is innovatively used as an active precursor, the directional anchoring effect of the organic acid sodium solution and the layered structure of the double hydroxide is utilized, the molecular dispersion of the organic acid root ions in the interlayer and the surface of the carrier is realized through stirring, and a uniform composite intermediate is formed; Subsequently, the loaded material is subjected to single-step temperature-controlled calcination under a protective atmosphere, and the following two processes are simultaneously completed: ① carrier conversion: the double hydroxide is dehydrated to form a high-stability double metal oxide skeleton; and ② active component in-situ generation: the organic acid sodium is thermally decomposed to form high-dispersion nanoscale sodium carbonate (Na2CO3), which breaks through the dispersion limitation of the traditional impregnation method for loading pre-prepared sodium carbonate and avoids the decomposition risk of the active component caused by high temperature of more than 800 DEG C.

[0039] Through the "layered precursor loading-in-situ synergistic thermal conversion" synergistic mechanism, the application realizes the strong interface coupling of the active component and the carrier, and significantly improves the structural stability and active site utilization rate of the material. The obtained adsorption material has the following core advantages: High-dispersion active sites: the in-situ generated Na2CO3 is nanoscale dispersed, and forms a chemical bonding interface with the double metal oxide carrier derived from the double hydroxide; Strengthened mass transfer path: the double metal oxide derived porous structure provides a through diffusion channel, and improves the CO2 adsorption kinetics; Cycle adaptability: the inorganic sodium carbonate active center can be regenerated under mild conditions, and the cycle stability is more than 85%.

[0040] The material is suitable for efficient capture of low-concentration CO2 in industrial flue gas (40-80 DEG C), and provides a low-cost and high-stability carbon emission reduction solution for high-emission industries such as steel and cement, and helps the green and low-carbon transformation.

[0041] The application provides a novel material capable of realizing atomic dispersion of an active component and establishing a stable chemical connection with a carrier and a corresponding preparation process, which takes into account the material performance and industrial economy, that is, while significantly improving the adsorption capacity, reaction rate and cycle life, the low cost of raw materials and manufacturing process is ensured, so as to meet the economic requirements of large-scale carbon capture of high-emission industries such as steel and cement.

[0042] The above scheme is further described in conjunction with specific examples; it should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present application, and the present application is not limited in scope by the following examples; the implementation conditions used in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0043] In the following examples, all raw materials are from commercial sources or prepared by conventional methods in the art, unless otherwise specified.

[0044] Nickel nitrate hexahydrate, purchased from Sinopharm Chemical Reagent Co., Ltd., brand LA15540100G; iron nitrate nonahydrate, purchased from Shanghai Aladdin Biochem Technology Co., Ltd., brand F100208; sodium citrate, purchased from Sinopharm Chemical Reagent Co., Ltd., brand 39476468; sodium hydroxide, purchased from Sinopharm Chemical Reagent Co., Ltd., brand 10019718; sodium carbonate, purchased from Sinopharm Chemical Reagent Co., Ltd., brand 10019260; nickel chloride hexahydrate, purchased from Sinopharm Chemical Reagent Co., Ltd., brand LA14366250G; polyethyleneimine, purchased from Shanghai Titan Science and Technology Co., Ltd., brand 01123103; activated alumina, purchased from Shanghai Titan Science and Technology Co., Ltd., brand 016271065. Example 1

[0045] This example provides a carbon dioxide adsorption material and a preparation method thereof, the preparation method comprising: Take 3.7 g of nickel nitrate hexahydrate and 5.0 g of iron nitrate nonahydrate, dissolve them in 50 mL of deionized water, and stir for 1 hour to form a uniform transparent stable mixed solution. Then, slowly add 50 mL of 0.75 mol / L sodium carbonate aqueous solution to the above solution, and drop 3 mol / L sodium hydroxide aqueous solution to adjust the pH of the system to 10, and stir at 60°C for 12 hours. After stirring, the product is washed with deionized water until the pH of the filtrate is about 7, then washed with anhydrous ethanol for 3 times, and dried in a 60°C drying box for 4 hours to obtain a layered double metal hydroxide material; Take 6 g of sodium citrate and dissolve it in 50 mL of deionized water, and stir until completely dissolved; take 5 g of the above double metal hydroxide material and slowly add it to the sodium citrate aqueous solution, and stir at room temperature for 10 hours. After stirring, the product is washed with deionized water and anhydrous ethanol alternately for 3 times, and dried in a 60°C drying box for 4 hours to obtain a double metal hydroxide loaded sodium citrate material; The material obtained in the above step is placed in a porcelain boat and heated at a temperature increasing rate of 5 ℃ / min from room temperature to 600 ℃ under N2 atmosphere, and then isothermal calcination is performed for 4 hours. Then, the material is cooled to room temperature to obtain a double metal oxide loaded sodium carbonate material, i.e. a carbon dioxide adsorption material. Example 2:

[0046] The present example provides a carbon dioxide adsorption material and a preparation method thereof, the preparation method comprising: 3.1 g of nickel chloride hexahydrate and 5.0 g of iron nitrate nonahydrate are weighed and dissolved in 50 mL of deionized water, and stirred for 1 hour to form a uniform transparent stable mixed solution. Then, 50 mL of 0.75 mol / L sodium carbonate aqueous solution is slowly added to the above solution, and 3 mol / L sodium hydroxide aqueous solution is added dropwise to adjust the pH of the system to 10, and stirred at 60 ℃ for 12 hours. After stirring, the product is washed with deionized water until the pH of the filtrate is about 7, and then washed with anhydrous ethanol for 3 times, and dried in a 60 ℃ drying box for 4 hours to obtain a layered double metal hydroxide material; 6 g of sodium citrate is weighed and dissolved in 50 mL of deionized water, and stirred until completely dissolved; 5 g of the above double metal hydroxide material is slowly added to the sodium citrate aqueous solution, and stirred at room temperature for 10 hours. After stirring, the product is washed with deionized water and anhydrous ethanol alternately for 3 times, and dried in a 60 ℃ drying box for 4 hours to obtain a double metal hydroxide loaded sodium citrate material; The material obtained in the above step is placed in a porcelain boat and heated at a temperature increasing rate of 5 ℃ / min from room temperature to 600 ℃ under N2 atmosphere, and then isothermal calcination is performed for 4 hours. Then, the material is cooled to room temperature to obtain a double metal oxide loaded sodium carbonate material, i.e. a carbon dioxide adsorption material. Example 3:

[0047] The present example provides a carbon dioxide adsorption material and a preparation method thereof, the preparation method comprising: 3.1 g of nickel chloride hexahydrate and 5.0 g of iron nitrate nonahydrate are weighed and dissolved in 50 mL of deionized water, and stirred for 1 hour to form a uniform transparent stable mixed solution. Then, 50 mL of 0.75 mol / L sodium carbonate aqueous solution is slowly added to the above solution, and 3 mol / L sodium hydroxide aqueous solution is added dropwise to adjust the pH of the system to 10, and stirred at 60 ℃ for 12 hours. After stirring, the product is washed with deionized water until the pH of the filtrate is about 7, and then washed with anhydrous ethanol for 3 times, and dried in a 60 ℃ drying box for 4 hours to obtain a layered double metal hydroxide material; Take 6 g of sodium citrate and dissolve it in 50 mL of deionized water, and stir until completely dissolved; take 5 g of the above bimetallic hydroxide material and slowly add it to the sodium citrate aqueous solution, and stir at room temperature for 10 hours. After stirring is completed, the product is washed with deionized water and anhydrous ethanol alternately for 3 times, and dried in a 60°C drying oven for 4 hours to obtain a bimetallic hydroxide loaded sodium citrate material; Place the material obtained in the above step flat in a porcelain boat, and under N2 atmosphere, increase the temperature from room temperature to 550°C at a rate of 5°C / min, and keep the temperature constant for 4 hours. Then cool to room temperature to obtain a bimetallic oxide loaded sodium carbonate material, which is a carbon dioxide adsorption material.

[0048] Comparative Example 1: This example provides a carbon dioxide adsorption material and a preparation method thereof, which comprises: Take 3.7 g of nickel nitrate hexahydrate and 5.0 g of iron nitrate nonahydrate, and dissolve them in 50 mL of deionized water, and stir for 1 hour until a uniform transparent stable mixed solution is formed. Then, slowly add 50 mL of a 0.75 mol / L sodium carbonate aqueous solution to the above solution, and drop 3 mol / L sodium hydroxide aqueous solution to adjust the pH of the system to 10, and stir at 60°C for 12 hours. After stirring is completed, the product is washed with deionized water until the pH of the filtrate is about 7, and then washed with anhydrous ethanol for 3 times, and dried in a 60°C drying oven for 4 hours to obtain a bimetallic hydroxide material; Place the bimetallic hydroxide material flat in a porcelain boat, and under N2 atmosphere, increase the temperature from room temperature to 600°C at a rate of 5°C / min, and keep the temperature constant for 4 hours. Then cool to room temperature to obtain a bimetallic oxide material; Finally, an organic amine is loaded onto the bimetallic oxide material prepared according to the above method by using an impregnation method: dissolve 6 g of polyethyleneimine (PEI) in 50 mL of ethanol, and after stirring uniformly, add 5 g of the fully dried adsorption material intermediate-bimetallic oxide material prepared according to the above method, and stir at room temperature for 10 hours. After stirring is completed, wash with anhydrous ethanol for 3 times, and dry in a 60°C drying oven for 4 hours to obtain an amine functionalized bimetallic oxide carbon dioxide adsorption material, which is referred to as a carbon dioxide adsorption material.

[0049] Comparative Example 2: This example provides a carbon dioxide adsorption material and a preparation method thereof, which comprises: Weigh 6 g of sodium citrate and dissolve it in 50 mL of deionized water, stirring until completely dissolved. Slowly add 5 g of activated alumina powder to the sodium citrate solution and stir at room temperature for 10 hours. After stirring, wash the product three times alternately with deionized water and anhydrous ethanol, and dry it in a 60℃ drying oven for 4 hours to obtain alumina-supported sodium citrate material. The material obtained in the previous step was spread evenly and placed in a ceramic boat. Under a nitrogen atmosphere, the temperature was increased from room temperature to 600 °C at a rate of 5 °C / min, and calcined at this temperature for 4 hours. Then, it was cooled to room temperature to obtain alumina-supported sodium carbonate carbon dioxide adsorbent material, or simply carbon dioxide adsorbent material.

[0050] Comparative Example 3: This example provides a carbon dioxide adsorption material and its preparation method, which includes: Weigh 3.7 g of nickel nitrate hexahydrate and 5.0 g of ferric nitrate nonahydrate, dissolve them in 50 mL of deionized water, and stir for 1 hour until a homogeneous, transparent, and stable mixed solution is formed. Then, slowly add 50 mL of 0.75 mol / L sodium carbonate aqueous solution to the above solution, while simultaneously adding 3 mol / L sodium hydroxide aqueous solution dropwise to adjust the pH of the system to 10. Stir at 60 °C for 12 hours. After stirring, wash the product with deionized water until the pH of the filtrate is approximately 7, then wash three times with anhydrous ethanol, and dry in a drying oven at 60 °C for 4 hours to obtain the bimetallic hydroxide material. Weigh 6 g of sodium carbonate and dissolve it in 50 mL of deionized water, stirring until completely dissolved. Slowly add 5 g of the above bimetallic hydroxide material to the sodium carbonate aqueous solution and stir at room temperature for 10 hours. After stirring, wash the product three times alternately with deionized water and anhydrous ethanol, and dry it in a drying oven at 60℃ for 4 hours to obtain the bimetallic hydroxide directly supported sodium carbonate material. The material obtained in the previous step was spread evenly and placed in a ceramic boat. Under a N2 atmosphere, the temperature was increased from room temperature to 600 °C at a rate of 5 °C / min, and calcined at this temperature for 4 hours. Then, it was cooled to room temperature to obtain a bimetallic oxide-supported sodium carbonate carbon dioxide adsorbent material, or simply a carbon dioxide adsorbent material.

[0051] Comparative Example 4: This example provides a carbon dioxide adsorption material and its preparation method, which includes: Take 3.7 g of nickel nitrate hexahydrate and 5.0 g of iron nitrate nonahydrate, dissolve them in 50 mL of deionized water, and stir for 1 hour to form a uniform transparent stable mixed solution. Then, slowly add 50 mL of 0.75 mol / L aqueous sodium carbonate solution to the above solution, while adding 3 mol / L aqueous sodium hydroxide solution to adjust the pH of the system to 10, and stir at 60℃ for 12 hours. After stirring, the product is washed with deionized water until the pH of the filtrate is about 7, and then washed with anhydrous ethanol 3 times, and dried in a 60℃ drying oven for 4 hours to obtain a bimetallic hydroxide material; Place the bimetallic hydroxide material flat in a porcelain boat, and heat it from room temperature to 600℃ at a rate of 5℃ / min under N2 atmosphere, and calcine at 600℃ for 4 hours. Then cool to room temperature to obtain a bimetallic oxide material; Take 6 g of sodium citrate and dissolve it in 50 mL of deionized water, and stir until completely dissolved; take 5 g of the above bimetallic oxide material and slowly add it to the aqueous sodium citrate solution, and stir at room temperature for 10 hours. After stirring, the product is washed with deionized water and anhydrous ethanol alternately 3 times, and dried in a 60℃ drying oven for 4 hours to obtain a step-by-step bimetallic oxide loaded sodium citrate material; Place the material obtained in the above step flat in a porcelain boat, and heat it from room temperature to 600℃ at a rate of 5℃ / min under N2 atmosphere, and calcine at 600℃ for 4 hours. Then cool to room temperature to obtain a step-by-step bimetallic oxide loaded sodium carbonate carbon dioxide adsorption material, which is referred to as carbon dioxide adsorption material.

[0052] Performance test: Place the material obtained above into a fixed bed adsorption device for carbon dioxide adsorption and desorption performance test. 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 arranged outside. The reaction temperature deviation is less than ±0.5℃, and the reactor is filled with ultra-fine glass wool at both ends to reduce the loss of adsorbent during the test.

[0053] Take 1.2 g of the material obtained in Examples 1-3 and Comparative Examples 1-4, and uniformly fill into a fixed bed reactor. First, the adsorbent is heated and pretreated at 373 K for 1 hour under a high-purity N2 atmosphere at 100 mL / min, so as to remove impurities in the adsorbent by blowing. After the reactor is cooled to the required experimental temperature (333 K) and stabilized, the gas circuit is switched to a simulated flue gas containing 10% CO2 at 100 mL / min, and a CO2 adsorption experiment is performed. The CO2 concentration at the outlet of the fixed bed is measured by a CO2 analyzer, and when the outlet CO2 concentration is equal to the inlet concentration, it is proved that the adsorption is saturated. According to the change of the CO2 concentration at the outlet of the fixed bed at different times, the breakthrough curve is drawn. The CO2 adsorption amount can be obtained by integrating the area of the breakthrough curve under the conditions of CO2 inlet concentration, flow rate, etc., and the integral calculation formula is as follows.

[0054]

[0055] wherein in the formula, Q is the CO2 adsorption amount of the adsorbent (mmol / g), m is the mass of the adsorbent (g), v is the flow rate of the inlet gas (mL / min), C0 is the CO2 concentration at the inlet of the fixed bed reactor (vol.%), C is the CO2 concentration at the outlet of the fixed bed reactor (vol.%), t is the adsorption time (s), P is the experimental operating pressure (kPa), T is the experimental temperature (K), R is the gas constant (8.314 J mol -1 K -1 ).

[0056] Subsequently, the desorption performance and cycle stability test are carried out. After the adsorption is completed, the gas flow is switched to N2 at 100 mL / min, and the temperature is raised to 423 K for desorption experiment, and when the CO2 gas concentration at the outlet of the fixed bed is 0, it is proved that the adsorbent has been regenerated. The CO2 adsorption / desorption experiment is repeated several times to investigate the cycle stability of the adsorbent.

[0057] (1) Figs. 1-2 The scanning electron microscope (SEM) images of the sodium carbonate dioxide adsorption material prepared by the double metal oxide supported on carbon at different magnifications are shown in the figure. The images clearly show the composite structure of the double metal oxide skeleton and the highly dispersed nano active sites. Under low magnification, open and interconnected sheet-shaped pore networks are visible, which provide good channels for gas diffusion. Under high magnification, dozens of nanometer sodium carbonate particles are uniformly embedded on the surface of the carrier and the inner wall of the pore, showing a strong interface coupling state, and there is no obvious agglomeration or blockage. The morphology effectively realizes the nanometerization of the active component and the strong interface combination, which is the key structural basis for its high adsorption capacity and excellent cycle stability; (2) The specific surface area data of different adsorption materials are shown in Table 1.

[0058]

[0059] From Table 1, in addition to the specific surface area of Comparative Example 2 being larger due to the particle size of 30 nm of the alumina, Examples 1-3 all exhibit excellent specific surface areas, which is due to the synergistic regulation of the carrier structure according to the application. It is believed that the specific surface area of Comparative Example 1 is the worst, which is probably due to the pore blockage caused by the organic amine (PEI) covering the surface of the double metal oxide and the high-temperature treatment, significantly reducing the porosity; Comparative Example 3 is easy to partially dissolve and lose in the washing process due to the direct loading of sodium carbonate, and the large particles of sodium carbonate block the carrier pores; the step-by-step calcination process of Comparative Example 4 is easy to make the double metal oxide skeleton densification, and it is difficult to penetrate the internal pores when loading sodium citrate later, and the active component is only attached to the surface of the particles after calcination, causing the pore volume to collapse. In contrast, the present application realizes the uniform loading of nano-sodium carbonate while constructing hierarchical pores through the molecular-level dispersion of sodium citrate between the double metal hydroxide layers and in-situ calcination conversion, so that the high specific surface area and the effectiveness of the active sites reach the best balance.

[0060] (3) The adsorption capacity and cycle stability data of different adsorption materials are shown in Table 2.

[0061]

[0062] From the data in Table 2, the CO2 adsorption performance and cycle stability of Examples 1-3 and Comparative Examples 1-4 show significant differences, and the specific analysis is as follows: Example 1: The initial adsorption capacity is 3.7 mmol / g, and after 10 cycles, it remains at 3.2 mmol / g (retention rate of about 86.5%). It is believed that its advantage should be due to the directional anchoring of sodium citrate between the double metal hydroxide layers, and the formation of a strong chemical bonding interface between the nano-sodium carbonate and the double metal oxide through in-situ calcination, which synergistically guarantees the stability of the highly dispersed active sites.

[0063] Example 2: The initial adsorption capacity is 3.6 mmol / g, and after 10 cycles, it remains at 3.0 mmol / g (retention rate of about 83.3%). Its performance is slightly lower than that of Example 1, which is believed to be mainly due to the use of nickel chloride hexahydrate as the nickel source, and the possible partial retention of chloride ions (Cl - ) during the calcination process, which may slightly affect the formation of the double metal oxide carrier structure, and may result in a lower dispersion of active sites or a lower optimization of the carrier pore structure than the nickel nitrate precursor of Example 1, but the core "sodium citrate-carrier synergistic in-situ conversion" still guarantees excellent cycle stability, and the performance is significantly better than all the comparative examples.

[0064] Example 3: The initial adsorption capacity is 3.2 mmol / g, and remains at 2.7 mmol / g after 10 cycles (retention rate of about 84.4%). Its adsorption capacity is the lowest among the three, but the cycle retention rate is slightly higher than that of Example 2. Analysis suggests that its performance characteristics may be caused by two process adjustments: one is the use of nickel chloride precursor, which brings similar structural effects as Example 2; the other is the reduction of the calcination temperature to 550°C. Lower calcination temperature may not fully convert the double metal hydroxide to oxide (support solidification), resulting in insufficient mechanical strength and stability of the support skeleton; but at the same time, low temperature is more conducive to inhibiting the sintering and growth of sodium carbonate nanocrystals, making them more dispersed. The trade-off between these two effects ultimately results in a lower capacity but still good cycle stability.

[0065] Comparative Example 1 (amine functionalization): The adsorption capacity drops to 1.4 mmol / g after 10 cycles (retention rate of about 50%). Analysis suggests that the performance decline may be mainly due to the oxidative decomposition and volatilization of polyethyleneimine (PEI) during regeneration, resulting in irreversible loss of active sites.

[0066] Comparative Example 2 (alumina support): Although the support itself has good stability (about 83.3% retention rate after 10 cycles), the adsorption performance is poor (initial adsorption capacity of 3.0 mmol / g, lower than 3.7 mmol / g of Example 1). Analysis suggests that Al2O3 may not be able to anchor sodium citrate through Ni 2+ , Fe 3+ coordination as double metal hydroxide, resulting in easy slight agglomeration of sodium carbonate generated by calcination and weak combination with the support; although its specific surface area reaches 200 m 2 / g, the pores are disordered, part of the sodium carbonate blocks the pores or is difficult to contact CO2, and Al2O3 has no active sites to assist in activating CO2, so the performance is limited by single adsorption of sodium carbonate.

[0067] Comparative Example 3 (direct loading of sodium carbonate): The adsorption capacity drops to 1.4 mmol / g after 10 cycles (retention rate of about 45.2%). Its performance has declined seriously, and analysis suggests that this may be due to the partial dissolution and loss of sodium carbonate during washing caused by direct addition of sodium carbonate; and sodium carbonate is easy to recrystallize, forming large particles that block the pores after calcination; the physical adsorption interface is easy to peel off.

[0068] Comparative Example 4 (step calcination): The adsorption capacity drops to 2.0 mmol / g after 10 cycles (retention rate of about 69.0%). Its performance is not good, and analysis suggests that this may be due to the densification of the double metal oxide skeleton caused by the first calcination, and the active components loaded subsequently are only physically attached to the surface without strong interaction force, which is severely detached under thermal stress.

[0069] In summary, the composite structure with nanodispersed active interface and stable hierarchical pores is successfully constructed by in-situ anchoring and synergistic temperature control calcination strategy of sodium organic acid as precursor in layered double hydroxide, which makes the material exhibit high CO2 adsorption capacity (3.7 mmol / g) and excellent cycle stability (about 86.5% retention rate after 10 cycles), significantly better than traditional impregnation method and step-by-step loading process, confirming the key role of the synergistic mechanism of "precursor molecular dispersion-in-situ conversion" in improving the adsorption performance and material stability.

[0070] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

[0071] The endpoints of the ranges and any values disclosed in this document are not limited to the precise values recited as exactly that endpoint point, but rather to also be understood as including values approximately around or close to that value as if stated in the specification. For ranges, the endpoints are included between each respective range, between the respective range endpoints and the individual points, and between the individual points, as if stated in the specification.

Claims

1. A carbon dioxide adsorbent material, characterized by, The raw material of the carbon dioxide adsorption material comprises a double-metal hydroxide loaded organic acid sodium material, the double-metal hydroxide loaded organic acid sodium material comprises a layered double-metal hydroxide and organic acid sodium dispersed at a molecular level and loaded on the double-metal hydroxide; The carbon dioxide adsorption material comprises a double-metal oxide loaded sodium carbonate material, and the raw material is subjected to a chemical conversion treatment to generate the double-metal oxide loaded sodium carbonate material.

2. The carbon dioxide adsorbent material of claim 1, wherein, The chemical conversion treatment comprises a calcination treatment; further, the calcination temperature of the calcination treatment is 450-600°C.

3. The carbon dioxide adsorbent material of claim 1, wherein, In the double-metal oxide loaded sodium carbonate material, the sodium carbonate exists in the form of nanoparticles with an average particle size of 10-100 nm; and / or, the double-metal oxide loaded sodium carbonate material forms an open, interconnected pore network structure; and / or, the specific surface area of the double-metal oxide loaded sodium carbonate material is greater than or equal to 150 m 2 / g, and further 150-200 m 2 / g. In the double-metal oxide loaded sodium carbonate material, the sodium carbonate exists in the form of nanoparticles with an average particle size of 10-100 nm; and / or, the double-metal oxide loaded sodium carbonate material forms an open, interconnected pore network structure; and / or, the specific surface area of the double-metal oxide loaded sodium carbonate material is greater than or equal to 150 m 2 / g, and further 150-200 m 2 / g.

4. A method for producing a carbon dioxide adsorbing material, characterized by, The preparation method of the carbon dioxide adsorption material comprises: adding a layered double-metal hydroxide into an organic acid sodium solution, stirring and dispersing, separating, obtaining a double-metal hydroxide loaded organic acid sodium material, and then performing a calcination treatment under a protective atmosphere.

5. The method of claim 4, wherein the carbon dioxide adsorbent material is prepared by a process comprising: The feeding mass ratio of the double-metal hydroxide to the organic acid sodium is controlled to be 1:1-3; and / or, the mass concentration of the organic acid sodium solution is controlled to be 0.05-0.25 g / mL; and / or, the organic acid sodium solution is prepared by dispersing organic acid sodium in water.

6. The method of claim 4, wherein the carbon dioxide adsorbent material is prepared by a process comprising: The double-metal hydroxide is a nickel-iron hydroxide; and / or, the organic acid sodium comprises one or more selected from a combination of sodium citrate, sodium malate and sodium acetate.

7. The method of claim 4, wherein the carbon dioxide adsorbent material is prepared by a process comprising: The calcination temperature of the calcination treatment is controlled to be 450-600°C; and / or, the calcination time of the calcination treatment is controlled to be 2-6 hours; and / or, the temperature rising rate of the calcination treatment is controlled to be 4-8°C / min; and / or, the protective atmosphere is formed by introducing nitrogen and / or inert gas.

8. The method of claim 4, wherein the carbon dioxide adsorbent material is prepared by a process comprising: The layered double-metal hydroxide is prepared by the following method: The nickel salt and the iron salt are dispersed in water to obtain a nickel-iron solution, then a sodium carbonate aqueous solution with a volume difference of less than 5% from the nickel-iron solution is added, sodium hydroxide or an aqueous solution thereof is used to adjust the pH value of the system to be 9.5-10.5, and the layered double-metal hydroxide is generated under a heating condition with stirring.

9. The method of claim 8, wherein the carbon dioxide adsorbent material is prepared by a process comprising: The nickel salt is one or more selected from a combination of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate; and / or, the iron salt is one or more selected from a combination of iron chloride, iron sulfate and iron nitrate; and / or, the mass ratio of the nickel salt to the iron salt is 1-4:1; and / or, the total concentration of the nickel salt and the iron salt in the nickel-iron solution is 0.5-1 mol / L; and / or, the concentration of the sodium carbonate aqueous solution is 0.5-1 mol / L; and / or, when the aqueous sodium hydroxide solution is used to adjust the pH value of the system, the concentration of the aqueous sodium hydroxide solution is 2-4 mol / L; and / or, the heating condition is controlled to make the stirring be performed at a temperature of 40-80°C, and further, the stirring time is controlled to be 8-12 hours.

10. Application of the carbon dioxide adsorption material in any one of claims 1-4 or the carbon dioxide adsorption material prepared by the preparation method in any one of claims 5-9 in a carbon dioxide adsorption device.

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