Choline chloride-based carbon capture material and method of making same

Abstract

The present application relates to carbon capture material technical field, especially based on a kind of choline chloride carbon capture material and preparation method thereof.The terephthalic acid is dissolved in water, different concentrations of choline chloride are added and stirred uniformly, then chromium nitrate is added, then it is placed in ultrasonic oscillator and shaken for 30min, 40% concentration hydrofluoric acid is dropped while stirring, then the reactant is added into reaction kettle, and based on choline chloride carbon capture material n-ChCl-MIL-101(Cr) is prepared by reacting at 220 DEG C for 8h.The present application studies the influence of the concentration of choline chloride on the structure of material and CO2 adsorption performance, and the results show that, with the increase of the concentration of choline chloride, the change trend of CO2 adsorption capacity is volcano-shaped, and the CO2 adsorption capacity of 0.075-ChCl-MIL-101(Cr) is best, and the unique pore cage structure of MIL-101(Cr) can well adsorb CO2.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture materials, and in particular to a choline chloride-based carbon capture material and a preparation method thereof. Background Art

[0002] Along with industrialization, greenhouse gas emissions, primarily carbon dioxide, have caused global warming, posing a serious threat to human development. CO2 capture is a key technology for addressing this challenge. CO2 capture has four application scenarios: pre-combustion capture, oxyfuel combustion, post-combustion capture, and direct air capture. These scenarios correspond to CO2 concentrations of 15% to 60%, 75% to 90%, 4% to 15%, and 0.02% to 0.04%, respectively.

[0003] Currently, absorption is the most widely used decarbonization technology for high-concentration CO2 capture. Its core materials are inorganic alkali or organic amine solutions. However, this technology suffers from significant issues such as high regeneration energy consumption and pipeline corrosion, resulting in high decarbonization costs. In recent years, adsorption has gained widespread favor due to its high overall stability and low regeneration energy consumption. It is particularly favored for low-concentration (≤15%) CO2 capture and is considered a promising new generation of CO2 capture technology. The key to adsorption lies in the development of adsorption materials with high adsorption capacity, high selectivity, and high stability.

[0004] Currently commonly used adsorption materials include carbon-based materials, zeolites, silica and MOFs-type porous adsorption materials. Among them, MOFs materials have high crystallinity, high specific surface area and adjustable pore structure, and have shown considerable potential in the field of CO2 capture. However, when these existing carbon-based materials are used as carbon capture materials, they can only capture CO2 according to the physical structural characteristics of the materials, such as the pores of the materials. This method cannot bring out the best capture performance of the materials. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing a carbon capture material based on choline chloride, so as to obtain a carbon capture material with better capture performance.

[0006] To achieve the above object, the application provides the following technical scheme: a preparation method of a choline chloride-based carbon capture material is as follows: 0.996 g of terephthalic acid is dissolved in water, different concentrations of choline chloride are added and stirred uniformly, then 2.4 g of chromium nitrate is added, and then the mixture is put into an ultrasonic oscillator and shaken for 30 min, 0.26 ml of 40% hydrofluoric acid is added dropwise while stirring, the reaction mixture is put into a reaction kettle and placed in an oven at 220 DEG C for 8 h; after cooling, a green product is obtained, solid-liquid separation is carried out by using a centrifuge, then N, N-dimethylformamide and anhydrous ethanol are used for washing respectively until the liquid color does not change, and after suction filtration, the product is placed in an 80 DEG C oven and dried for 8 h to obtain the choline chloride-based carbon capture material, which is marked as n-ChCl-MIL-101(Cr), wherein n represents the concentration of choline chloride.

[0007] The addition amount of choline chloride is 0.005 mol-0.4 mol.

[0008] The choline chloride-based carbon capture material prepared by the above method is used for CO2 adsorption, and the CO2 adsorption breakthrough experiment includes the following steps:

[0009] S401, before starting the adsorption experiment, 1 g of n-ChCl-MIL-101(Cr) is put into a quartz glass tube, and cotton balls are used to fix both ends;

[0010] S402, the whole pipeline is purged with N2 until no CO2 concentration is detected by a CO2 gas analyzer, and then the adsorption experiment is started;

[0011] S403, two valves into the quartz glass tube are closed, and CO2 gas and N2 gas are introduced, preliminary calibration is carried out through a glass rotameter, and then secondary calibration is carried out through a soap bubble flowmeter, wherein the flow ratio of CO2 to N2 is 1:85;

[0012] S404, when the calibration is completed, the two valves into the glass quartz tube are opened, and the two valves into the soap bubble flowmeter are closed, and the fixed bed adsorption experiment is started, the CO2 concentration overflowing after the adsorption reaction is completed is monitored online, and the CO2 concentration at different times is obtained, and the monitoring is ended when the outlet CO2 concentration is equal to the CO2 concentration in the inlet mixed gas;

[0013] S405, the device and the whole gas pipeline are closed, the adsorption experiment is ended, and the adsorption breakthrough curve is drawn.

[0014] The application has the following technical effects and advantages:

[0015] This paper studies the effect of choline chloride concentration on material structure and CO2 adsorption performance. By establishing comparative samples and using adsorption experiments to analyze the adsorption behavior of composite materials for CO2, the results show that with the increase of choline chloride concentration, the change trend of CO2 adsorption capacity is volcanic, and the CO2 adsorption capacity of 0.075-ChCl-MIL-101(Cr) is the best. In addition, the unique pore cage structure of MIL-101(Cr) can adsorb CO2 well. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is an X-ray diffraction analysis diagram of the carbon capture material prepared in the present invention.

[0017] Figure 2 Scanning electron microscope analysis of the carbon capture material prepared in the present invention (wherein a is MIL-101(Cr), b is 0.075-ChCl-MIL-101(Cr), c is 0.1-ChCl-MIL-101(Cr), and d is 0.125-ChCl-MIL-101(Cr)).

[0018] Figure 3 This is a graph showing the N2 adsorption breakthrough curve of the carbon capture material prepared in the present invention (where a is MIL-101(Cr), b is 0.075-ChCl-MIL-101(Cr), c is 0.1-ChCl-MIL-101(Cr), and d is 0.125-ChCl-MIL-101(Cr)).

[0019] Figure 4 This is an infrared spectrum curve of the carbon capture material prepared in the present invention.

[0020] Figure 5 This is a thermogravimetric analysis diagram of the carbon capture material prepared in the present invention (wherein, a is MIL-101(Cr), b is 0.075-ChCl-MIL-101(Cr), c is 0.1-ChCl-MIL-101(Cr), and d is 0.125-ChCl-MIL-101(Cr)).

[0021] Figure 6 This is a comparison chart of the adsorption capacity of the carbon capture materials prepared in the present invention (where a is MIL-101(Cr), b is 0.075-ChCl-MIL-101(Cr), c is 0.1-ChCl-MIL-101(Cr), and d is 0.125-ChCl-MIL-101(Cr)).

[0022] Figure 7Elemental composition analysis diagram of the carbon capture material prepared in the present invention (wherein a is MIL-101(Cr), b is 0.075-ChCl-MIL-101(Cr), c is 0.1-ChCl-MIL-101(Cr), and d is 0.125-ChCl-MIL-101(Cr)).

[0023] Figure 8 This is an analysis chart of the CO2 adsorption capacity of the carbon capture material prepared in the present invention (where a is MIL-101(Cr), b is 0.075-ChCl-MIL-101(Cr), c is 0.1-ChCl-MIL-101(Cr), and d is 0.125-ChCl-MIL-101(Cr)).

[0024] Figure 9 This is the adsorption breakthrough curve of the carbon capture material prepared in the present invention.

[0025] Figure 10 This is an analysis diagram of the adsorption-desorption cycle of the carbon capture material prepared in the present invention.

[0026] Figure 11 This is a fitting curve diagram of the carbon capture material prepared in the present invention at different temperatures and pressures (where a is the adsorption amount of different materials under increasing pressure, and b is a comparison of the adsorption amount of 0.075-ChCl-MIL-101 at different temperatures).

[0027] Figure 12 Schematic diagram of the CO2 adsorption and penetration experimental device of the present invention. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] Example 1

[0030] 0.996 g of terephthalic acid was dissolved in 28.6 ml of deionized water, and 0.075 mol of choline chloride was added and stirred evenly. Then, 2.4 g of chromium nitrate nonahydrate was added and the mixture was placed in an ultrasonic oscillator and shaken for 30 minutes. 0.26 ml of 40% hydrofluoric acid was added dropwise while stirring. The reactants were then added to a reactor and placed in an oven at 220° C. for 8 hours. After cooling, a green product was obtained. The solid-liquid separation was performed by centrifuge and the product was washed several times with N,N-dimethylformamide and anhydrous ethanol until the liquid color did not change. After filtration, the product was dried in an 80° C. oven for 8 hours. Finally, the green product was placed in a sealed bag and labeled as 0.075-ChCl-MIL-101(Cr) for storage.

[0031] The crystal structures of MIL-101(Cr) and n-ChCl-MIL-101(Cr) were determined by X-ray diffractometer, and phase analysis was performed on the adsorbent samples, including analyzing the diffraction patterns and determining the peak positions of the samples, thereby understanding the composition, internal atomic or molecular structure and morphology of the samples. The X-ray diffractometer test conditions included a Cu target, Kα rays, a tube voltage and current of 40 kV and 40 mA, respectively, a scanning speed of 0.5° / min, and a scanning 2θ range of 5° to 80°.

[0032] The X-ray diffraction patterns of adsorbents MIL-101(Cr), 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) are shown in Figure 2. Figure 1 As shown, compared with the standard diffraction peaks of MIL-101(Cr), the diffraction peaks 2θ of MIL-101(Cr) are 8.4°, 9.04° and 16.48°, confirming the reconstruction of MIL-101(Cr). After modification with choline chloride, the diffraction peak at 8.4° weakened, and showed a volcano-shaped trend with increasing concentration and was inversely proportional to the carbon dioxide adsorption content. The diffraction peak near 16.8° enhanced, and showed a volcano-shaped trend with increasing concentration and was proportional to the carbon dioxide adsorption content. As the concentration increased, a new diffraction peak appeared at 27.5° in 0.125-ChCl-MIL-101, but its relationship with the carbon dioxide adsorption amount could not be directly determined. It was preliminarily judged that the addition of choline chloride to modify MIL-101(Cr) mainly affected the two diffraction peaks of 8.4° and 16.8°, and was inversely proportional to the increase of the diffraction peak at 8.4° and directly proportional to the increase of the diffraction peak at 16.8°. Both diffraction peaks showed a volcano-shaped trend with concentration.

[0033] The prepared MIL-101(Cr) and n-ChCl-MIL-101(Cr) were dissolved in anhydrous ethanol and then ultrasonicated. The samples were then dropped onto a conductive copper plate and finally gold-sprayed for characterization to observe the morphological characteristics of different adsorbents.

[0034] Scanning electron microscopy images of adsorbents MIL-101(Cr), 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) are shown in Figure 2. Figure 2 As shown. Figure 2 In (a), MIL-101(Cr) has a regular octahedral structure; Figure 2 (b) It can be seen that after the two are combined, the skeleton structure of MIL-101(Cr) begins to change from smooth to rough because ChCl is attached to the surface of MIL-101(Cr). The crystalline morphology can also be observed from the internal pores of 0.075-ChCl-MIL-101(Cr) after magnification, which is consistent with the results of FT-IR analysis. In addition, with the continuous attachment of ChCl, the uniform channels inside MIL-101(Cr) begin to fold and bend, which may be because ChCl filling the MIL-101(Cr) channels slightly changes the surface morphology of MIL-101(Cr). Comparison Figure 2 As shown in (b), (c), and (d), after ChCl loading, the skeleton structure of MIL-101(Cr) becomes rougher and more defective, and the curvature of its internal channels deepens, indicating that the ChCl load acts on the surface and internal channel structure of MIL-101(Cr). At the same time, the morphology of MIL-101(Cr) also undergoes distortion and agglomeration, indicating that ChCl has also been successfully loaded into MIL-101(Cr). With the increase of ChCl loading, the structure of MIL-101(Cr) becomes rougher and the distortion deepens, indicating that more ChCl molecules are filled in the pores of the MIL-101(Cr) skeleton.

[0035] N2 adsorption analysis was performed using a N2 adsorption instrument to determine the N2 adsorption or desorption isotherms of MIL-101(Cr) and n-ChCl-MIL-101(Cr) at a liquid nitrogen temperature of 77K, and the samples were degassed at 100°C for 6 hours before testing.

[0036] The adsorption breakthrough curves of adsorbents MIL-101(Cr), 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) are shown in Figure 2. Figure 3As shown in Figure 1, the isothermal trend lines show that MIL-101(Cr), 0.1-ChCl-MIL-101(Cr), and 0.125-ChCl-MIL-101(Cr) all belong to Type I isotherms, while 0.075-ChCl-MIL-101(Cr) belongs to Type II isotherms. The N2 adsorption / desorption isotherms of these four different adsorbents appear similar, yet there are significant differences. Figure (a) shows that the adsorption / desorption curves are almost identical, demonstrating that the adsorption / desorption process does not produce a hysteresis loop. This indicates that the pore structure of this adsorbent is relatively small and contains a large number of micropores, resulting in an adsorption capacity of 610.2472 cc / g. As can be seen in Figure (b), there is an inflection point at approximately P / P0 = 0.2, which is the first steep point of the isotherm and represents the saturated adsorption capacity of the single molecule, indicating that the adsorption capacity is complete. However, the adsorption capacity still exceeds that of the unmodified MIL-101(Cr), reaching 641.8073cc / g. As can be seen in Figure (c), although the 0.1 mol / l choline chloride modification has the best nitrogen adsorption and desorption effect, reaching 830.8252cc / g, a narrow hysteresis loop appears at approximately P / P0 = 0.18, indicating that the 0.1-ChCl-MIL-101(Cr) sample contains a large number of mesopores and relatively few micropores. As can be seen from Figure (d), the adsorption and desorption curves basically overlap, and only when P / P0 is 0.17 and P / P0 is 0.97, a narrow hysteresis loop appears, indicating that there are a large number of mesopores and relatively few micropores. Its adsorption capacity is 582.5392cc / g.

[0037] Fourier transform infrared spectrometer was used to analyze MIL-101(Cr) and n-ChCl-MIL-101(Cr). MIL-101(Cr) and n-ChCl-MIL-101(Cr) were dried to remove water, mixed with potassium bromide, pressed into pellets, and fixed in a sample cell to record infrared spectra. The wavenumber range was set to 4000 cm' to 500 cm'.

[0038] The infrared spectra of adsorbents MIL-101(Cr), 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) are shown in Figure 2. Figure 4 As shown. At 586cm -1 There is a Cr-O vibration absorption peak at 740 cm -1 and 827cm -1 The CH vibration peak adjacent to the benzene ring appears at 1279cm -1 It is proved to be aromatic acid at 1400cm -1 C=O vibration on the symmetrical carboxylate, 1549.6 cm-1 The characteristic peak of benzene ring is at 3409cm -1 The characteristic peaks of carboxylate indicate that MIL-101(Cr) was successfully synthesized. Moreover, after adding different concentrations of ChCl, the peak at 3000 cm -1 -3400cm -1 The characteristic peak showed a large pure peak, proving that a large number of hydroxyl groups were introduced. This result further proved that the ChCl modification was successful.

[0039] The thermal stability of MIL-101(Cr) and n-ChCl-MIL-101(Cr) was analyzed using a thermogravimetric analyzer, and the relationship between heat change and temperature was recorded. The heating rate of the experiment was 5°C / min, and the temperature was increased to 700°C.

[0040] The thermogravimetric curves of adsorbents MIL-101(Cr), 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) are shown in Figure 2. Figure 5 The thermogravimetric analysis of MIL-101(Cr) mainly consists of three stages. The small amount of weight loss before 100℃ is due to the larger pore cage (approximately ) releases water molecules. The weight loss at 100-200℃ is due to the escape of solvent molecules from the medium pore cage (approx. ); after 200°C, the material rapidly loses weight, and the MIL-101(Cr) framework decomposes. As the hydroxyl groups in the skeleton are removed, the structure begins to collapse. Therefore, MIL-101(Cr) can maintain structural stability at temperatures around 200°C, with a mass loss of 71.71%. After modification with the addition of choline chloride, thermal stability and residual mass are significantly improved. 0.075-ChCl-MIL-101(Cr) can maintain structural stability at temperatures around 400°C, with a mass loss of 52.49%, a 59.54% increase in residual mass compared to the raw material. However, as the concentration of choline chloride increases, the thermal stability and residual mass begin to slowly decrease. This is because choline chloride decomposes under high temperature conditions, resulting in greater mass loss at higher concentrations, but still exceeding that of the raw material.

[0041] EDS analysis uses an incident electron beam to excite the primary X-rays of MIL-101(Cr) and n-ChCl-MIL-101(Cr). The element types are analyzed according to the different wavelengths and energies of the characteristic X-rays. At the same time, the composition of each component in the sample material is determined by comparing the contents of the four elements C, Cr, Cl and N.

[0042] The EDS of adsorbents MIL-101(Cr), 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) are as follows Figure 7 As shown. The final sample material after processing will lose some material during the experiment. The type and specific gravity of the characteristic elements on the surface of the material can be analyzed by energy spectrum to reflect the true composition and proportion of the material. Figure (a) shows the Cr and C elements of the typical MIL-101 (Cr) structure. Cr and Cl can be observed in Figures (b), (c), and (d), indicating that the two materials are successfully composited, which is consistent with the SEM results. In addition, combined with the content in the table, it can be seen that with the increase of the ChCl impregnation amount, the actual amount of ChCl loaded in the sample increases, which is consistent with the results of FT-IR analysis, thermal stability analysis, and SEM analysis.

[0043] The adsorption experiment is to conduct a CO2 adsorption penetration experiment; specifically, the CO2 adsorption penetration experiment includes the following steps:

[0044] S401, before starting the adsorption experiment, 1 g of MIL-101(Cr) or n-ChCl-MIL-101(Cr) was placed in a quartz glass tube and both ends were fixed with cotton balls;

[0045] S402, first purge the entire pipeline with N2 until the CO2 gas analyzer can no longer detect the CO2 concentration and then start the adsorption experiment;

[0046] S403, close the two valves entering the quartz glass tube, and introduce CO2 gas and N2 gas at the same time. First, perform preliminary calibration through the glass rotor flowmeter, and then enter the soap bubble flowmeter for secondary calibration. The flow ratio of CO2 to N2 is 15:85.

[0047] S404: After the calibration is completed, the two valves entering the glass quartz tube are opened, and the two valves entering the soap bubble flowmeter are closed. The fixed bed adsorption experiment is started, and the concentration of CO2 overflowing after the adsorption reaction is completed is monitored online to obtain the CO2 concentration at different times. The monitoring is terminated when the outlet CO2 concentration is monitored to be the same as the CO2 concentration in the inlet mixed gas.

[0048] S405, close the device and the entire gas path, end the adsorption experiment and draw the adsorption breakthrough curve.

[0049] MIL-101 adsorption experimental device for low concentration CO2 Figure 12As shown in the figure, the experimental device mainly consists of four systems: a gas supply system, a flow detection system, a fixed-bed adsorption system, and a data acquisition system. The gas supply system consists of a CO2 gas cylinder, an N2 gas cylinder, a pressure gauge, and a pressure reducing valve. N2 is used for purging pretreatment of the experimental device, mixing CO2 and N2 gases. Both gas flows are controlled by a rotor flowmeter and then corrected by a soap bubble flowmeter. The fixed-bed adsorption system is mainly used for adsorption experiments. The fixed bed size is a high-temperature resistant quartz glass tube with an inner diameter of 5mm, an outer diameter of 8mm, and a length of 120mm. The adsorbent is filled in the tube. The data acquisition system is a CO2 gas analyzer that measures the CO2 concentration.

[0050] The adsorbent was placed under vacuum conditions at 120°C for 6 h and then the adsorption process was repeated four times. The adsorption amount was compared to determine the adsorbent stability.

[0051] The adsorption performance of n-ChCl-MIL-101(Cr) and MIL-101(Cr) modified with different concentrations of choline chloride is shown in Figure 2. Figure 8 As shown in the figure, under the same experimental conditions, the modification of MIL-101(Cr) and different concentrations of choline chloride is slightly different.

[0052] The adsorption capacities of 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) were 17.8972cc / g, 28.8487cc / g, 20.6239cc / g and 27.4263cc / g, respectively. The maximum CO2 adsorption capacity Q of MIL-101(Cr) modified with choline chloride at different concentrations was 0.075 >Q 0.125 >Q 0.1 >Q MIL-101(Cr) , the carbon dioxide adsorption capacity increased by 61.191%, 15.235% and 53.243% after modification respectively. It can be inferred that its adsorption performance and carbon dioxide adsorption capacity are volcanic, and the maximum adsorption capacity is reached at a concentration of 0.075 mol / l.

[0053] The adsorption breakthrough curves of adsorbents MIL-101(Cr), 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) are shown in Figure 2. Figure 9As shown in the figure, the CO2 adsorption breakthrough curves of the adsorbent materials modified with different concentrations are relatively similar, all changing from steep to gentle; the breakthrough time of MIL-101(Cr) is between 12-17 minutes, the breakthrough time of 0.075-ChCl-MIL-101(Cr) is between 24-31 minutes, the breakthrough time of 0.1-ChCl-MIL-101(Cr) is between 16-22 minutes, and the breakthrough time of 0.125-ChCl-MIL-101(Cr) is between 22-27 minutes. Among them, the breakthrough time of 0.075 mol / l choline chloride modification is the longest, indicating that the choline chloride modification with this concentration has the best adsorption effect on carbon dioxide.

[0054] The adsorption-desorption cycles of adsorbents MIL-101(Cr), 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) were as follows: Figure 10 The results show that the maximum difference in adsorption capacity is less than 4%, indicating that no material decomposition and loss occurred during the cycle. This proves the durability of the synthesized material.

[0055] Adsorbents MIL-101(Cr), 0.075-ChCl-MIL-101(Cr), 0.1-ChCl-MIL-101(Cr) and 0.125-ChCl-MIL-101(Cr) were adsorbed at different pressures. Figure 11 (a) is shown. The adsorption of CO2 by adsorbent 0.075-ChCl-MIL-101(Cr) at different temperatures is shown in Figure 11 (b) shows that the equilibrium amount of carbon dioxide adsorption is inversely proportional to temperature. This is because adsorption is generally exothermic. Therefore, as long as adsorption equilibrium is reached, increasing the temperature will reduce adsorption.

[0056] Using origin fitting, the Freundlich equation better fits the CO2 adsorption isotherm of the modified material than the Langmuir equation, indicating that the adsorption behavior of the choline chloride-modified material on heterogeneous surfaces is more consistent with multilayer non-ideal adsorption. The introduction of choline chloride increases the sample's adsorption capacity for CO2. The composite material with a concentration of 0.075 mol / l exhibits the best CO2 adsorption, reaching an adsorption saturation of 28.8487 cc / g at 293K and 100 kPa, suggesting that it is a promising carbon dioxide adsorbent. Adsorption is an exothermic process, so the material's adsorption capacity decreases with increasing temperature.

[0057] Example 2

[0058] Example 1

[0059] Example 2

[0060] Example 3

[0061] Example 4

[0062] Example 5

[0063] Example 6

[0064] 0.996g of terephthalic acid was dissolved in 28.6ml of deionized water, 0.4mol of choline chloride was added and stirred evenly, followed by 2.4g of chromium nitrate nonahydrate. The mixture was placed in an ultrasonic oscillator and vibrated for 30 minutes. 0.26ml of 40% hydrofluoric acid was then added dropwise while stirring. The reaction mixture was then placed in a reactor and placed in an oven at 220°C for 8 hours. After cooling, a green product was obtained. The product was centrifuged for solid-liquid separation and then washed several times with N,N-dimethylformamide and anhydrous ethanol until the liquid color did not change. After filtration, the product was dried in an 80°C oven for 8 hours. The green product was then placed in a sealed bag and stored as 0.4-ChCl-MIL-101(Cr). The product was used for carbon dioxide adsorption (the specific method was the same as in Example 1), with an adsorption capacity of 0.6cc / g.

[0065] Comparative Example 1

[0066] Dissolve 0.996g of terephthalic acid in 28.6ml of deionized water, add 2.4g of chromium nitrate nonahydrate, and shake in an ultrasonic oscillator for 30 minutes. Then, add 0.26ml of 40% hydrofluoric acid dropwise while stirring. Then, add the reactants to a reactor and place it in an oven at 220°C for 8 hours. After cooling, a green product is obtained. The solid-liquid separation is performed by centrifuge, and then the product is washed multiple times with N,N-dimethylformamide and anhydrous ethanol until the liquid color does not change. After filtration, dry in an 80°C oven for 8 hours. Finally, the green product is placed in a sealed bag and labeled as MIL-101(Cr) for storage.

[0067] Comparative Example 2

[0068] 0.996 g of terephthalic acid was dissolved in 28.6 ml of deionized water, 0.125 mol of choline amino acid was added and stirred evenly, followed by the addition of 2.4 g of chromium nitrate nonahydrate. The mixture was placed in an ultrasonic oscillator and shaken for 30 minutes. 0.26 ml of 40% hydrofluoric acid was then added dropwise with stirring. The reaction mixture was then placed in a reactor and placed in an oven at 220°C for 8 hours. After cooling, a green product was obtained. The solid-liquid separation was performed by centrifuge, followed by multiple washings with N,N-dimethylformamide and anhydrous ethanol until the liquid color did not change. After filtration, the product was dried in an 80°C oven for 8 hours. Finally, the green product was placed in a sealed bag. This product was used for carbon dioxide adsorption (the specific method was the same as in Example 1), with an adsorption capacity of 4.3 cc / g.

Claims

1. A method for preparing a carbon capture material based on choline chloride, characterized in that: The preparation method comprises the following steps: dissolving terephthalic acid in water, adding choline chloride and stirring evenly, then adding chromium nitrate, and then vibrating the mixture in an ultrasonic oscillator for 30 minutes. Then, 40% hydrofluoric acid is added dropwise while stirring. The reactants are then added to a reactor and placed in an oven at 220° C. for reaction for 8 hours. After cooling, a green product is obtained. The product is centrifuged, washed, filtered, and then dried to obtain a choline chloride-based carbon capture material labeled as n-ChCl-MIL-101(Cr).

2. The method for preparing a carbon capture material based on choline chloride according to claim 1, characterized in that: The mass volume ratio of terephthalic acid, chromium nitrate and 40% hydrofluoric acid is: 0.996g:2.4g:0.26mL.

3. The method for preparing a carbon capture material based on choline chloride according to claim 1, characterized in that: The amount of choline chloride added is: 0.005mol-0.4mol.

4. The method for preparing a carbon capture material based on choline chloride according to claim 1, characterized in that: The product was separated by centrifuge, washed with N,N-dimethylformamide and anhydrous ethanol respectively, and dried in an oven at 80°C for 8 h.

5. A choline chloride-based carbon capture material prepared by the method according to any one of claims 1 to 4.

6. An application of a choline chloride-based carbon capture material prepared by the method according to any one of claims 1 to 4, characterized in that: The carbon capture material is used for CO2 adsorption.

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