Intelligent adsorption and desorption integrated carbon capture material as well as preparation method and application thereof

Abstract

The invention provides an intelligent adsorption and desorption integrated carbon capture material as well as a preparation method and application thereof. The carbon capture material comprises: a composite aerogel fiber, which comprises aramid nanofibers and carbon nanotubes, the aramid nanofibers and the carbon nanotubes are mutually lapped to form a three-dimensional porous structure, and the three-dimensional porous structure comprises mesopores and macropores; the mesopores of the three-dimensional porous structure of the composite aerogel fiber are at least filled with the liquid carbon absorbent, and the surface of the composite aerogel fiber is coated with the liquid carbon absorbent. According to the carbon capture material provided by the invention, the confined and loaded liquid carbon absorbent provides richer active adsorption sites for CO2, and macropores at the fiber lap joint in the composite aerogel fiber provide effective channels for CO2 diffusion, so that the carbon capture material has excellent carbon adsorption performance; wherein the carbon nanotube can endow the carbon capture material with excellent photo-thermal performance, so that photo-thermal desorption of the carbon capture material is realized.

Description

Technical Field

[0001] This invention belongs to the field of carbon capture material technology, specifically relating to an intelligent adsorption-desorption integrated carbon capture material, its preparation method, and its application. Background Technology

[0002] With the continuous growth of the global population and the ongoing industrialization process, carbon dioxide emissions are rising year by year, and the greenhouse effect is intensifying. Carbon reduction has become a core issue of widespread international concern. Direct air carbon capture (DAC) technology can directly capture carbon dioxide from the atmosphere, and then permanently convert or store the captured CO2 to achieve carbon reduction targets. Compared to traditional coal-fired power plants or industrial flue gas capture methods, DAC does not need to consider nitrogen oxides (NOx). x ) and sulfur oxides (SO x Due to the influence of gaseous impurities such as carbon dioxide, the device is relatively small in scale and supports modular construction. Its location is not limited by the location and type of emission sources, thus possessing greater flexibility and broad deployment potential. In addition, DAC devices can be combined with low-carbon energy sources such as solar energy, industrial waste heat, and geothermal energy. If renewable energy and CO2 storage or utilization facilities can be located nearby, carbon emission reduction efficiency can be maximized and CO2 transportation costs can be reduced.

[0003] Currently, carbon dioxide capture technologies can be categorized into liquid absorption and solid adsorption methods based on material type. In solid adsorption methods, porous solid materials such as activated carbon, zeolite molecular sieves, metal-organic frameworks, and aerogels are used. The capture mechanism relies on physical adsorption through weak van der Waals forces between the material surface and CO2 molecules, or chemical adsorption through the formation of chemical bonds at higher temperatures. Although solid adsorption methods exhibit advantages such as low cost, low energy consumption, and low corrosivity, their adsorption capacity is limited, severely restricting their performance in practical applications. Meanwhile, liquid absorption methods based on liquid absorbent materials, while possessing high CO2 absorption capacity, are highly corrosive and limited by a diffusion-dominated mass transfer mechanism, resulting in limited effective contact sites between the target ions and CO2 molecules and low mass transfer efficiency. Summary of the Invention

[0004] To solve all or part of the above-mentioned technical problems, the present invention provides the following technical solutions: A first aspect of the present invention provides a smart adsorption-desorption integrated carbon capture material, comprising: Composite aerogel fiber, comprising aramid nanofibers and carbon nanotubes, wherein the aramid nanofibers and carbon nanotubes overlap to form a three-dimensional porous structure, and the three-dimensional porous structure includes mesopores and macropores. Liquid carbon absorbent is at least filled in the mesopores of the three-dimensional porous structure of the composite aerogel fiber and coats the surface of the composite aerogel fiber.

[0005] In the carbon capture material provided by this invention, a liquid carbon absorbent (which can react with CO2 through chemisorption) is filled at least through capillary action within the mesopores of the three-dimensional porous structure of the composite aerogel fibers. This confined loading of liquid carbon absorbent provides more abundant active adsorption sites for CO2. Furthermore, the macropores at the fiber overlaps in the composite aerogel fibers provide effective channels for CO2 diffusion, thereby improving mass transfer efficiency. Therefore, compared to a simple liquid carbon absorbent, this carbon capture material exhibits superior carbon adsorption performance. Additionally, the carbon nanotubes in the composite aerogel fibers endow the carbon capture material with excellent photothermal properties, enabling photothermal desorption.

[0006] In some embodiments, the total mass percentage of aramid nanofibers and carbon nanotubes in the carbon trapping material is 25 wt.% to 70 wt.%.

[0007] In some embodiments, the mass ratio of aramid nanofibers to carbon nanotubes is 10:1 to 10:5. Excessive carbon nanotube content leads to excessively high viscosity of the spinning solution, while insufficient carbon nanotube content results in inadequate photothermal performance during subsequent photothermal desorption, increasing desorption energy consumption. Therefore, controlling the mass ratio of aramid nanofibers to carbon nanotubes within the range of 10:1 to 10:5 is a preferred embodiment.

[0008] In some embodiments, the mass percentage of liquid carbon absorbent in the carbon capture material is 30 wt.% to 75 wt.%.

[0009] In some embodiments, the liquid carbon absorbent includes one or more of organic amine absorbents and / or piperazine absorbents.

[0010] In some embodiments, the organic amine absorbent includes one or more of polyethyleneimine, branched polyethyleneimine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, ethylenediamine, and hydroxyethylethylenediamine, but is not limited thereto.

[0011] In some embodiments, the piperazine absorbent includes one or more of aminoethylpiperazine and piperazine.

[0012] In some embodiments, the porosity of the composite aerogel fiber is above 80%, for example, 80% to 99%.

[0013] In some embodiments, the pore volume of the composite aerogel fiber is 0.1 cm³. 3 / g or more, for example, 0.1cm 3 / g~1cm 3 / g.

[0014] In some embodiments, the composite aerogel fiber contains macropores (pore size, for example, 50 nm to 100 nm) accounting for 5% to 15% of the volume, and mesopores (pore size, for example, 1 nm to 50 nm) accounting for 85% to 95% of the volume. Thus, the abundant mesopores provide capillary confinement for the liquid carbon absorbent, while the abundant macropores provide an effective channel for carbon dioxide diffusion.

[0015] In some embodiments, the composite aerogel fiber contains fibers with a diameter of 200µm to 5 mm.

[0016] In some embodiments, the aspect ratio of the fibers contained in the composite aerogel fiber is 10~10. 7 .

[0017] In some embodiments, the specific surface area of ​​the composite aerogel fiber is 1 m². 2 / g~200 m 2 / g.

[0018] A second aspect of the present invention provides a method for preparing an intelligent adsorption-desorption integrated carbon capture material, the method comprising: Composite hydrogel fibers were prepared by using wet spinning technology to produce a dispersion containing aramid nanofibers and carbon nanotubes. The composite hydrogel fibers were then subjected to solvent replacement and drying in sequence to obtain composite aerogel fibers; Liquid carbon absorbent is filled into the three-dimensional porous structure of the composite aerogel fiber, and the liquid carbon absorbent is coated on the surface of the composite aerogel fiber to obtain a carbon capture material.

[0019] In some embodiments, the preparation method includes: dissolving the liquid carbon absorbent in tert-butanol to prepare an absorbent solution, wherein the mass ratio of the liquid carbon absorbent to tert-butanol is 1:10~30; impregnating the composite aerogel fiber with the absorbent solution to fill the three-dimensional porous structure of the composite aerogel fiber with the liquid carbon absorbent and coat its surface, thereby obtaining a carbon trapping material. Using tert-butanol to prepare the liquid carbon absorbent solution can reduce the viscosity of the liquid carbon absorbent and improve its wetting effect with the solid substrate. Systematic studies have found that when the mass ratio of the liquid carbon absorbent to tert-butanol is within the above range, it exhibits good wetting properties and solid-liquid composite kinetics.

[0020] In some embodiments, the preparation method specifically includes: impregnating the composite aerogel fiber in the absorbent solution, then applying a force of a preset intensity to the composite aerogel fiber impregnated with the absorbent solution to cause it to aggregate into a fiber aggregate, purging the fiber aggregate to remove excess absorbent solution, and then drying to obtain the carbon capture material.

[0021] In some embodiments, the immersion time is 0.1 h to 1 h.

[0022] In some embodiments, the preset force is 0.01 N to 2 N, so that pores are retained between the overlapping aramid nanofibers and carbon nanotubes. If the force is too strong, the pores between the overlapping aramid nanofibers and carbon nanotubes will be excessively eliminated, making it difficult for carbon dioxide to diffuse into the fiber interior, thus affecting its air permeability and adsorption performance.

[0023] In some embodiments, the fiber aggregate is placed between two sheets of filter paper and then purged until no residual liquid layer remains on the surface of the filter paper, thereby completing the removal of excess absorbent solution.

[0024] In some embodiments, the purging rate is 1 mL / min to 10 mL / min, and the purging time is 0.1 min to 2 min.

[0025] In some embodiments, the fiber aggregates are purged to remove excess absorbent solution, and then dried at atmospheric pressure at 80°C to 120°C or freeze-dried under vacuum.

[0026] In some embodiments, the impregnation and drying steps may be repeated multiple times to ensure that the liquid carbon absorbent is fully filled and coated. The number of impregnations may be, for example, 1 to 10 times, and the number of drying cycles may be, for example, 1 to 10 times.

[0027] In some embodiments, the content of aramid nanofibers in the dispersion is 0.1 wt.% to 2 wt.%, and the content of carbon nanotubes is 0.01 wt.% to 0.5 wt.%.

[0028] In some embodiments, the dispersion is injected into a coagulation bath using a needle with an inner diameter of 200 µm to 5 mm to obtain the composite aerogel fibers containing fibers with a diameter of 200 µm to 5 mm.

[0029] In some embodiments, the coagulation bath includes one or more of the following: calcium chloride solution, aniline hydrochloride solution, hydrochloric acid solution, sulfuric acid solution, a mixture of sodium hydroxide in water and ethanol, a mixture of sodium hydroxide in water and tert-butanol, and a reducing agent solution, but is not limited thereto.

[0030] In some embodiments, the solvent replacement includes: replacing the obtained composite hydrogel fiber with deionized water 2-3 times, and then replacing it with a mixed solution of tert-butanol and water 2-3 times until the pores of the gel fiber are uniformly filled with the mixed solution of tert-butanol and water, and then drying it.

[0031] In some embodiments, the product after solvent replacement is dried, for example, by special drying methods such as supercritical drying or freeze drying.

[0032] In some embodiments, the liquid carbon absorbent includes one or more of organic amine absorbents and / or piperazine absorbents.

[0033] In some embodiments, the organic amine absorbent includes one or more of polyethyleneimine, branched polyethyleneimine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, ethylenediamine, and hydroxyethylethylenediamine, but is not limited thereto.

[0034] In some embodiments, the piperazine absorbent includes one or more of aminoethylpiperazine and piperazine.

[0035] The "intelligent adsorption-desorption integrated carbon capture material" described in the first aspect of this invention can be prepared by the "preparation method of an intelligent adsorption-desorption integrated carbon capture material" described in the second aspect of this invention.

[0036] A third aspect of the present invention provides a smart adsorption-desorption integrated carbon capture material prepared by the preparation method described in any of the technical solutions.

[0037] In some embodiments, the carbon dioxide adsorption capacity of the prepared carbon capture material is 0.1 mmol / g to 2 mmol / g.

[0038] The fourth aspect of the present invention provides the application of the intelligent adsorption-desorption integrated carbon capture material described in any of the technical solutions in direct CO2 air capture, flue gas capture, preparation of woven carbon adsorbent materials or wearable carbon adsorbent materials.

[0039] A fifth aspect of the present invention provides a carbon capture method, comprising: adsorbing carbon dioxide using a smart adsorption-desorption integrated carbon capture material as described in any of the technical solutions of the present invention.

[0040] In some embodiments, the carbon capture method is direct air capture.

[0041] In some embodiments, the direct air capture method includes: placing the carbon capture material in an adsorption tower, introducing air into the adsorption tower, so that the air comes into full contact with the carbon capture material, thereby allowing the carbon capture material to adsorb carbon dioxide.

[0042] In some embodiments, an air compressor or air cylinder is used to introduce air into the adsorption tower, with the gas flow rate set to 1~100 mL / min and the carbon dioxide concentration to 380~400 ppm.

[0043] The sixth aspect of the present invention provides a method for photothermal desorption of carbon dioxide from a carbon capture material, comprising: irradiating the intelligent adsorption-desorption integrated carbon capture material of any of the technical solutions of the present invention, which has adsorbed carbon dioxide, with light to achieve carbon dioxide desorption.

[0044] In some embodiments, the intensity of the light is 1000 W / m². 2 ~2000 W / m 2 The illumination time only needs to be sufficient to achieve desorption, for example, more than 1 minute, such as 1 minute to 90 minutes.

[0045] For example, the photothermal desorption method for carbon dioxide specifically includes: after adsorption is completed in the adsorption tower, irradiating the carbon capture material adsorbed with carbon dioxide with light, and introducing nitrogen gas into the adsorption tower, with a gas flow rate of 0.1 mL / min to 30 mL / min.

[0046] Compared with the prior art, the present invention has at least some or all of the following beneficial effects: (1) In the carbon capture material provided by the present invention, the liquid carbon absorbent (which can react with CO2 through chemisorption) is filled at least through capillary action in the mesopores of the three-dimensional porous structure of the composite aerogel fiber, and the confined liquid carbon absorbent provides more abundant active adsorption sites for CO2; and the macropores at the fiber overlaps in the composite aerogel fiber provide effective channels for CO2 diffusion to improve mass transfer efficiency. Therefore, compared with the simple liquid carbon absorbent, this carbon capture material exhibits superior carbon adsorption performance. In addition, the carbon nanotubes in the composite aerogel fiber can endow the carbon capture material with excellent photothermal properties, thereby enabling it to achieve photothermal desorption.

[0047] (2) The carbon capture material preparation process provided by the present invention is simple, the reaction conditions are mild, and it is suitable for large-scale production.

[0048] (3) The carbon capture material provided by the present invention can be applied to direct air capture of carbon dioxide and low-energy photothermal desorption, and intelligent integrated adsorption and desorption, and has a wide range of application prospects. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic flowchart of the preparation method of Embodiment 1 of the present invention; Figure 2a This is an electron microscope image of the cross-section of the composite aerogel fiber in Example 1; Figure 2b This is an electron microscope image of the cross-section of the composite aerogel fiber in Example 1; Figure 2c This is an electron microscope image of the cross-section of the carbon capture material prepared in Example 1; Figure 2d This is an electron microscope image of the cross-section of the carbon capture material prepared in Example 1; Figure 3 This is a comparison chart of the viscosity of absorbent solutions with different mass ratios of branched polyethyleneimine to tert-butanol in Examples 3 and 7-11; Figure 4a The initial contact angle and the contact angle after 10 seconds of immersion between the absorbent solution and the composite aerogel fiber in Example 11 are shown. Figure 4b The initial contact angle and the contact angle after 10 seconds of immersion between the absorbent solution and the composite aerogel fiber in Example 3 are shown. Figure 4c These are the initial contact angles between the absorbent solution and the composite aerogel fiber in Example 8, and the contact angles after 10 seconds of immersion. Figure 5 The surface tension of absorbent solutions with different ratios of BPEI and tert-butanol in Examples 3 and 7-11 was characterized by the pendant drop method using a contact angle meter. Figure 6 These are the stress-strain curves of the composite aerogel fibers in Examples 1-6, obtained by measuring with a tensile testing machine. Figure 7 It is a woven material obtained by weaving the composite aerogel fiber of Example 3 in a warp and weft manner; Figure 8a The nitrogen adsorption-desorption isotherm of the composite aerogel fiber prepared in Example 3; Figure 8b This is a pore size distribution diagram of the composite aerogel fiber prepared in Example 3; Figure 9 These are thermogravimetric analysis diagrams of the composite aerogel fiber in Example 3 and the carbon capture material in Examples 3-11; Figure 10 The graph shows the change in adsorption capacity of the composite aerogel fiber in Example 3 and the carbon capture material in Examples 3-11 over time in a dry environment. Figure 11a This is a desorption heat test diagram of the carbon capture material in Example 15; Figure 11b This is a desorption heat test diagram of the carbon capture material in Example 8; Figure 12 This is a comparison graph showing the change in adsorption capacity of the carbon trapping materials in Examples 8 and 12-14 as a function of fiber diameter in a dry environment; Figure 13 The composite aerogel material in Example 3, and the carbon capture materials in Examples 3 and 7-10, are temperature change curves over time under simulated sunlight. Figure 14a These are images of a carbon capture material undergoing photothermal desorption performance testing under simulated sunlight conditions. Figure 14b This is a graph showing the change in carbon dioxide concentration at the inlet and outlet of the adsorption tower over time under simulated sunlight irradiation conditions using the carbon capture material of Example 8. Figure 15a These are images of the photothermal desorption performance test of carbon capture materials under outdoor natural light conditions; Figure 15b This is a graph showing the change in carbon dioxide concentration at the inlet and outlet of the adsorption tower over time under outdoor natural light irradiation conditions for the carbon capture material of Example 8. Figure 16 This is a cyclic adsorption stability diagram of the carbon capture material in Example 8; Figure 17 This is a schematic diagram illustrating the principle of direct CO2 air capture and intelligent desorption of the carbon capture material in this embodiment of the invention. Detailed Implementation

[0051] The invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as intended to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0052] In addition, unless otherwise specified, all raw materials used in the following embodiments can be purchased from the market or other sources, and all production and testing equipment used are known in the art, as are the testing methods used.

[0053] Example 1 This embodiment provides a smart adsorption-desorption integrated carbon capture material and its preparation method. Figure 1 This is a schematic flowchart of the preparation method in this embodiment, which specifically includes the following steps: (1) Single-walled carbon nanotubes were added to dimethyl sulfoxide to prepare a 0.2 wt.% single-walled carbon nanotube (CNT) dispersion; aramid nanofibers (ANF) and potassium tert-butoxide were added to dimethyl sulfoxide at a mass ratio of 1:1 to prepare an aramid nanofiber dispersion with a concentration of 2 wt.%; then the above single-walled carbon nanotube dispersion and aramid dispersion were mixed at a mass ratio of 1:1 and stirred evenly to obtain a mixed dispersion (containing 0.1 wt.% CNT and 1 wt.% ANF). (2) Using wet spinning technology, the above mixed dispersion was injected into a coagulation bath (pure water) through a needle with an inner diameter of 300 μm to obtain composite hydrogel fibers, and then freeze-dried to obtain composite aerogel fibers. (3) Using branched polyethyleneimine (BPEI) as a liquid carbon absorbent, 1 g of branched polyethyleneimine and 10 g of tert-butanol were mixed and stirred until uniform to form an absorbent solution. The composite aerogel fiber prepared above was immersed in the absorbent solution and completely wetted for 30 min. Then the fiber clump was picked up with tweezers, repeatedly wiped dry with qualitative filter paper, and a force of 2 N was applied to it and its shape was fixed as a disc. It was continuously blown three times with an air compressor at a flow rate of 10 mL / min until no liquid appeared on the filter paper. The liquid that was blown out was the liquid overlapping between the composite aerogel fibers, leaving the liquid in the fiber pores and a thin layer of liquid on the surface. Then it was placed in a freeze dryer for drying to obtain the carbon capture material.

[0054] Figure 2a , Figure 2b All images are electron microscope images of the cross-section of the composite aerogel fiber obtained by brittle fracture of the composite aerogel fiber in Example 1 in liquid nitrogen. Figure 2c , Figure 2d All images are electron microscope images of the cross-section of the composite aerogel fibers obtained by brittle fracture of the carbon trapping material prepared in Example 1 in liquid nitrogen.

[0055] Examples 2-6 Examples 2-6 are basically the same as Example 1, except that the concentration of single-walled carbon nanotubes in the dispersion is varied according to Table 1 in Examples 2-6. The rest are the same as in Example 1, and will not be described again here.

[0056] Table 1

[0057] Examples 7-11 Examples 7-11 are basically the same as Example 3, except that the mass ratio of branched polyethyleneimine to tert-butanol in the absorbent solutions prepared in Examples 7-11 varies as shown in Table 2. The rest of the procedures are the same as in Example 2 and will not be repeated here.

[0058] Table 2

[0059] Figure 3 This is a viscosity comparison chart of absorbent solutions with different mass ratios of branched polyethyleneimine to tert-butanol in Examples 3 and 7-11. Figure 3 It can be seen that as the mass percentage of tert-butanol increases, the viscosity of the absorbent solution decreases.

[0060] This invention characterizes the interfacial properties between absorbent solutions of different viscosities and composite aerogel fibers. The method includes measuring the change in contact angle between absorbent solutions of different ratios of BPEI and tert-butanol and composite aerogel fibers using a contact angle measuring instrument. Figure 4a , Figure 4b , Figure 4c The figures, in sequence, show the initial contact angle and the contact angle after 10 seconds of immersion between the absorbent solution and the composite aerogel fiber in Examples 11, 3, and 8. (Refer to reference...) Figure 4a , Figure 4b , Figure 4c It can be seen that the viscosity of the absorbent solution decreases with the increase of tert-butanol dosage. When the mass ratio of BPEI to tert-butanol is 1:20, the absorbent solution can completely impregnate the composite aerogel fiber within 10 seconds.

[0061] Figure 5 The surface tension of absorbent solutions with different ratios of BPEI and tert-butanol in Examples 3, 7-11 was characterized using the pendant drop method with a contact angle meter. Figure 5 As shown, as the proportion of BPEI decreases, the surface tension of the absorbent solution decreases, and the liquid can more easily penetrate into the three-dimensional porous structure of the composite aerogel fiber. It can be seen that the use of tert-butanol can significantly improve the composite kinetics between liquid carbon absorbent and solid composite aerogel fiber.

[0062] As can be seen from the above, the viscosity of the absorbent solution affects the liquid loading in the adsorbent. From the perspective of ensuring that the liquid carbon absorbent is fully filled into the composite aerogel fiber, the preferred mass ratio of liquid carbon absorbent to tert-butanol in the absorbent solution is in the range of 1:10 to 1:30.

[0063] Examples 12-14 Examples 12-14 are basically the same as Example 8, except that the inner diameter of the needle used in the wet spinning process of Examples 12-14 is different, as shown in Table 3. The rest are the same as in Example 8, and will not be described again here.

[0064] Table 3

[0065] Examples 15-18 Examples 15-18 are basically the same as Example 8, except that the types of liquid carbon absorbent used in the absorbent solution are varied according to Table 4, and are mixed with 20g of tert-butanol to prepare the absorbent solution. The rest are the same as in Example 8, and will not be described again here.

[0066] Table 4

[0067] The present invention tests the relevant properties of the composite aerogel fiber prepared in the above embodiments and the carbon capture material filled with liquid carbon absorbent.

[0068] 1. Characterization of the mechanical properties of composite aerogel fibers The testing method is as follows: the two ends of the composite aerogel fiber are fixed to the center of a customized "U"-shaped tensile test piece with glue, and the diameter of the fiber is measured using an optical microscope. Figure 6 These are the stress-strain curves of the composite aerogel fibers in Examples 1-6, obtained by measuring with a tensile testing machine. From... Figure 6 It can be seen that the tensile strength of the composite aerogel fibers in Examples 1-6 is in the range of 0.56~1.33 MPa, and the elongation at break is in the range of 3.85~13.32%, indicating that they have good weavability. Among them, the composite aerogel fiber in Example 5 has a tensile strength of 1.43 MPa and an elongation at break of 10%, exhibiting even better weavability. Figure 7 It is a woven material obtained by weaving the composite aerogel fiber of Example 3 in the form of warp and weft threads.

[0069] 2. Characterization of the porous structure of composite aerogel fibers The porous structure of the composite aerogel fibers prepared in the relevant embodiments was characterized. Figure 8a This is the nitrogen adsorption-desorption isotherm of the composite aerogel fiber in Example 3. Figure 8b This is a pore size distribution diagram of the composite aerogel fibers in Example 3. (See diagram for example.) Figure 8a , 8b It can be seen that the specific surface area of ​​the composite aerogel fiber is 183 m². 2 / g indicates that the composite aerogel fiber has a porous structure with a porosity of approximately 80% to 99%. Figure 8b The pore size distribution shows that mesopores account for about 5% to 15% and macropores account for about 85% to 95%.

[0070] 3. Thermogravimetric analysis (TG) of composite aerogel fibers and carbon capture materials The test method was as follows: Under a nitrogen atmosphere, the composite aerogel fiber in Example 3 and the carbon trapping material in the corresponding example were heated to 600°C at a heating rate of 10 K / min, and then subjected to thermogravimetric analysis. Figure 9 The results are obtained from thermogravimetric analysis. Due to the excellent thermal stability of solid materials, mass loss below 400 °C is negligible. In contrast, pure BPEI begins to decompose at 250 °C and completely evaporates at 400 °C. Therefore, the liquid loading ratio in the carbon capture material can be determined based on the mass loss within this temperature range. Tests show that the liquid loading ratios in the carbon capture materials of Examples 3, 7, 8, 9, and 10 are 75%, 60%, 52%, 45%, and 41%, respectively.

[0071] 4. Direct air carbon capture performance test of carbon capture materials The carbon capture materials in some of the embodiments were used to test the direct air carbon capture performance, with the composite aerogel fiber in Example 3 and simple BPEI as controls. The specific steps included: the carbon capture materials prepared in Examples 3 and 7-11 were placed in an 85 ℃ oven for 1 h to allow the fibers to be in a completely desorbed state. Then, the carbon capture materials were placed in an adsorption chamber, and simulated air (with a CO2 concentration of 400 ppm in the simulated air) was introduced at a flow rate of 40 ml / min. The changes in carbon dioxide concentration at the inlet and outlet were recorded using a carbon dioxide concentration meter, and the test temperature was 25 ℃. Figure 10 This is a graph showing the adsorption capacity of the carbon trapping materials in Examples 3 and 7-11 under dry conditions as a function of time. From... Figure 10 As can be seen, the carbon capture performance of the above-mentioned carbon capture materials ranges from 0.50 to 2.01 mmol / g, with the carbon capture performance of the carbon capture material in Example 8 being the best among these embodiments, at 2.01 mmol / g.

[0072] The adsorption capacity of pure BPEI is only 0.05 mmol / g. Compared with pure BPEI, the carbon capture performance of the carbon capture material prepared in the embodiments of the present invention is improved. This is because the mesoporous confined functional liquid inside the single fiber provides a large number of adsorption sites for carbon dioxide, and the gaps between the fibers provide diffusion channels for carbon dioxide. The reason why the carbon capture performance of the carbon capture materials of Examples 8 and 9 is better than that of Examples 3, 7, and 11 is that, under low loading, the number of contact sites between carbon dioxide and liquid carbon absorbent increases with the increase of loading, and the carbon dioxide adsorption performance increases. However, with further increase of loading, the thickness of liquid carbon absorbent on the surface of composite fiber increases, making it difficult for carbon dioxide to enter the liquid interior. It only adsorbs on the surface and becomes saturated, thus the adsorption performance relatively decreases. In addition, confining the liquid carbon absorbent in the composite aerogel fiber means that the liquid carbon absorbent does not directly contact the device during use, which can reduce its corrosiveness.

[0073] The present invention also tested the carbon capture performance of carbon capture materials containing different liquid carbon absorbents in Table 3 using the same method described above, and the test results are summarized in Table 5.

[0074] Table 5

[0075] 5. Direct air capture performance tests of carbon capture materials with different diameters The present invention tests the direct air capture performance of carbon capture materials in Examples 8 and 12-14, specifically including the following steps: carbon capture materials of different diameters are placed in an 85 ℃ oven for 1 h to allow them to be in a completely desorbed state. Then, the carbon capture materials are placed in an adsorption chamber, and simulated air (CO2 concentration 400ppm) is introduced at a gas flow rate of 40 ml / min. The changes in carbon dioxide concentration at the inlet and outlet are recorded using a carbon dioxide concentration meter. The test temperature is 25 ℃. Figure 12 This is a comparison chart showing the change in adsorption capacity of carbon-capturing materials with fiber diameter in a dry environment. From Figure 12 It is known that the adsorption performance of carbon capture materials decreases with increasing fiber diameter. This is because the smaller the diameter of the aerogel fibers, the shorter the diffusion path of gas on a single fiber during adsorption, resulting in a larger contact area between gas and liquid, which is more conducive to improving the adsorption kinetics of carbon dioxide. Therefore, the composite aerogel fibers of the carbon capture material of this invention preferably contain fibers with a diameter of 300 μm to 500 μm (which can be obtained by using needles with an inner diameter of 300 μm to 500 μm during wet spinning), which can further improve the adsorption performance of the carbon capture material.

[0076] 6. Desorption heat test of carbon capture materials containing different types of liquid carbon absorbents The present invention also characterizes the desorption thermal properties of carbon capture materials containing different types of liquid carbon absorbents. Specifically, the carbon capture materials prepared in Examples 15 and 8 are placed in a differential scanning calorimeter, nitrogen gas is introduced, the temperature is raised to 120°C at a heating rate of 10 k / min, stabilized for 10 min and then cooled to obtain DSC curves. Figure 11a This is a desorption heat test diagram of the carbon capture material in Example 15, in which... Figure 11a The ANF / CNT-TEPA in the middle represents the carbon capture material of Example 15; Figure 11b This is a desorption heat test diagram of the carbon capture material in Example 8, in which... Figure 11b ANF / CNT-BPEI represents the carbon capture material of Example 8. For example... Figure 11a , Figure 11b As shown, the heat of desorption of the liquid carbon absorbent in the carbon capture material of Example 15 is 100.6 KJ / mol, and the heat of desorption of the liquid carbon absorbent in the carbon capture material of Example 8 is 64.88 KJ / mol. It is evident that the carbon capture material loaded with BPEI has a low heat of desorption, which meets the requirements for low-temperature desorption.

[0077] 7. Photothermal performance testing of carbon capture materials The present invention also tests the photothermal performance of the carbon capture material, specifically including the following steps: a 30 cm condenser lens is placed under a solar simulator at a distance of 2.5 cm from the solar simulator so that the focused light can just cover the carbon capture material; the carbon capture material prepared in the corresponding embodiment is placed in a sealed acrylic plate, and the composite aerogel material in Example 3 is used as a control. Placing the sample in a sealed acrylic plate can reduce the influence of air convection on temperature; then a multifunctional data logger is used for temperature monitoring. Figure 13 The curves show the temperature change over time under simulated sunlight for the composite aerogel material in Example 3 and the carbon trapping material prepared in the corresponding examples. Figure 13 It can be seen that after the carbon capture material of Example 8 is exposed to light, it can rapidly heat up and the temperature can be stabilized at around 88 °C.

[0078] 8. Photothermal desorption performance test of carbon capture materials The test method was as follows: The carbon capture material of Example 8, which was saturated with adsorption, was placed in an adsorption tower, and the intensity of sunlight (1000 W / m²) was simulated using a solar simulator. 2 Irradiate the carbon capture material for 60 minutes, or irradiate the carbon capture material with outdoor natural light for 60 minutes, and introduce nitrogen gas into the adsorption tower at a gas flow rate of 30 ml / min. Use a carbon dioxide concentration meter to record the changes in carbon dioxide concentration at the inlet and outlet of the adsorption tower. Figure 14aThese images show the photothermal desorption performance of carbon trapping materials under simulated sunlight conditions. Figure 14b This is a graph showing the change in carbon dioxide concentration at the inlet and outlet of the adsorption tower over time under simulated sunlight irradiation conditions using the carbon capture material of Example 8. Calculations show that under a given sunlight intensity, the carbon capture material achieves a carbon dioxide desorption rate of approximately 85% over one hour. Figure 15a These images show the photothermal desorption performance of carbon capture materials under outdoor natural light conditions. Figure 15b The graph shows the change of carbon dioxide concentration at the inlet and outlet of the adsorption tower over time under outdoor natural light conditions for the carbon capture material of Example 8. It can be seen that under outdoor sunlight, the carbon dioxide desorption rate of this carbon capture material is 54% in one hour.

[0079] 9. Adsorption and desorption cycle stability test of carbon capture materials The test method was as follows: The carbon capture material of Example 8 was placed in a sealed chamber, and air was introduced into it at room temperature (humidity 60 RH%). The adsorption capacity was calculated by weighing. Then, the adsorption-saturated carbon capture material was placed in an 80°C oven, desorbed under vacuum, and then adsorbed again. This cycle was repeated multiple times. Figure 16 This is a cyclic adsorption stability diagram of the carbon capture material in Example 8. From... Figure 16 It can be seen that the adsorption cycle stability of this carbon capture material in air is good; after 10 cycles, the adsorption performance only decreases by about 14%.

[0080] Figure 17 This is a schematic diagram illustrating the principle of direct CO2 air capture and intelligent desorption of the intelligent adsorption-desorption integrated carbon capture material provided by this invention. The carbon capture material is placed in an adsorption tower, and air is introduced into the tower to complete the carbon capture process. Furthermore, when the carbon capture material is exposed to natural sunlight during the day, its excellent photothermal properties allow the sunlight to heat the material, causing it to desorb and release the adsorbed carbon dioxide, thus achieving intelligent adsorption-desorption of carbon dioxide.

[0081] In summary, the carbon capture material provided by this invention has excellent carbon adsorption performance, high carbon dioxide adsorption rate and adsorption capacity, as well as excellent flexibility, photothermal properties, and weavability. It has broad application prospects in fields such as direct air capture, photothermal intelligent desorption, or preparation of weavable adsorbent materials.

[0082] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0083] All aspects, embodiments, features, and examples of this invention should be considered illustrative and used to explain and illustrate the invention, but not to limit the invention. The scope of the invention is defined only by the claims.

[0084] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the described embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims.

Claims

1. A smart carbon capture material integrating adsorption and desorption, characterized in that, include: Composite aerogel fiber, comprising aramid nanofibers and carbon nanotubes, wherein the aramid nanofibers and carbon nanotubes overlap to form a three-dimensional porous structure, and the three-dimensional porous structure includes mesopores and macropores. Liquid carbon absorbent is at least filled in the mesopores of the three-dimensional porous structure of the composite aerogel fiber and coats the surface of the composite aerogel fiber.

2. The carbon capture material according to claim 1, characterized in that: The total mass percentage of aramid nanofibers and carbon nanotubes in the carbon trapping material is 25 wt.%~70 wt.%. And / or, the mass ratio of the aramid nanofibers to the carbon nanotubes is 10:1 to 10:5; And / or, the mass percentage of liquid carbon absorbent in the carbon capture material is 30 wt.%~75 wt.%; And / or, the liquid carbon absorbent comprises one or more of organic amine absorbents and / or piperazine absorbents; preferably, the organic amine absorbent comprises one or more of polyethyleneimine, branched polyethyleneimine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, ethylenediamine, and hydroxyethylethylenediamine; preferably, the piperazine absorbent comprises one or more of aminoethylpiperazine and piperazine. And / or, the composite aerogel fiber contains macropores accounting for 5% to 15% of the volume and mesopores accounting for 85% to 95% of the volume; And / or, the diameter of the composite aerogel fiber is 200 µm to 5 mm.

3. A method for preparing an intelligent adsorption-desorption integrated carbon capture material, characterized in that, include: Composite hydrogel fibers were prepared by using wet spinning technology to produce a dispersion containing aramid nanofibers and carbon nanotubes. The composite hydrogel fibers were then subjected to solvent replacement and drying in sequence to obtain composite aerogel fibers; Liquid carbon absorbent is filled into the three-dimensional porous structure of the composite aerogel fiber, and the liquid carbon absorbent is coated on the surface of the composite aerogel fiber to obtain a carbon capture material.

4. The preparation method according to claim 3, characterized in that: The liquid carbon absorbent is dissolved in tert-butanol to prepare an absorbent solution, wherein the mass ratio of the liquid carbon absorbent to tert-butanol is 1:10~30. The composite aerogel fiber is impregnated with the absorbent solution to obtain a carbon capture material. And / or, the dispersion contains aramid nanofibers at a content of 0.1 wt.% to 2 wt.% and carbon nanotubes at a content of 0.01 wt.% to 0.5 wt.%. And / or, the dispersion is injected into the coagulation bath using a needle with an inner diameter of 200 µm to 5 mm; And / or, the liquid carbon absorbent comprises one or more of organic amine absorbents and / or piperazine absorbents; preferably, the organic amine absorbent comprises one or more of polyethyleneimine, branched polyethyleneimine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, ethylenediamine, and hydroxyethylethylenediamine; preferably, the piperazine absorbent comprises one or more of aminoethylpiperazine and piperazine.

5. The preparation method according to claim 4, characterized in that, Specifically, it includes: The composite aerogel fiber is impregnated in the absorbent solution, and then a force of a preset strength is applied to the composite aerogel fiber impregnated with the absorbent solution to cause it to aggregate into a fiber aggregate. The fiber aggregate is then purged to remove excess absorbent solution, and then dried to obtain the carbon capture material.

6. The preparation method according to claim 5, characterized in that: The soaking time is 0.1 h to 1 h; And / or, the preset strength of the force is 0.01N~2N, so that pores are retained between the overlapping aramid nanofibers and carbon nanotubes; And / or, place the fiber aggregate between two sheets of filter paper and then purge it until there is no residual liquid layer on the surface of the filter paper.

7. The intelligent adsorption-desorption integrated carbon capture material prepared by the preparation method according to any one of claims 3 to 6.

8. The application of the intelligent adsorption-desorption integrated carbon capture material according to any one of claims 1, 2, and 7 in direct CO2 air capture, flue gas capture, preparation of woven carbon adsorbent materials or wearable carbon adsorbent materials.

9. A carbon capture method, characterized in that, Carbon dioxide is adsorbed using the intelligent adsorption-desorption integrated carbon capture material as described in any one of claims 1, 2, and 7.

10. A method for photothermal desorption of carbon dioxide from a carbon capture material, characterized in that, include: Irradiate the intelligent adsorption-desorption integrated carbon capture material according to any one of claims 1, 2, and 7, which has adsorbed carbon dioxide, to achieve carbon dioxide desorption.

Images