Multifunctional catalyst for regenerating carbon capture absorbent as well as preparation method and application of multifunctional catalyst

Abstract

The invention discloses a multifunctional catalyst for regeneration of a carbon capture absorbent and a preparation method and application thereof, and belongs to the technical field of catalysts.The preparation method comprises the following steps that a mixed solution of cobalt salt and inorganic transition metal salt and a 2-methylimidazole solution are mixed and then subjected to a hydrothermal reaction, then the obtained hydrothermal reaction product is subjected to heat treatment, and the multifunctional catalyst for regeneration of the carbon capture absorbent is obtained. The multifunctional catalyst is obtained. According to the present invention, the obtained multifunctional catalyst has the high specific surface area, the absorption and desorption cyclic loading amount of the absorbed CO2 can be increased by 28.9-68.6%, the activity regeneration of the SO2 poisoning absorbent can be achieved, the Fe ions in the absorbent can be removed by the prepared multifunctional catalyst, and the preparation method is simple, easy to operate and convenient to popularize and apply.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and in particular relates to a multifunctional catalyst for regenerating a carbon capture absorbent, and a preparation method and application thereof. Background Art

[0002] Chemical absorption, represented by alcoholamines, is the most technologically mature and adaptable CO2 capture technology for coal-fired flue gas. However, due to the large flue gas volume, traditional technologies have difficulty achieving deep removal of flue gas pollutants. Flue gas contains residual impurities such as SO2. Acidic SO2 combines with the absorbent to form highly stable, heat-stable sulfates, rendering the absorbent unable to regenerate. Furthermore, the absorbent is highly corrosive, etching the equipment and causing Fe ions to enter the absorbent. Furthermore, Fe ions, under the influence of O2 in the flue gas, accelerate the degradation of the absorbent into components such as acid and inorganic ammonia. Therefore, under the influence of impurities such as SO2 and Fe ions, the absorbent will gradually become poisoned or degrade and inactivate, making traditional alcoholamine-based carbon capture technology face the problem of poor stability. There is an urgent need to develop advanced SO2 and Fe ion removal processes to achieve highly stable CO2 capture.

[0003] In order to solve the problem of SO2 and coexisting Fe ions causing absorbent deactivation, the existing technology has focused a lot of research on the development of deep removal processes for flue gas pollutants and activated carbon adsorption processes. The deep removal process for flue gas pollutants mainly reduces the SO2 content entering the carbon capture system by optimizing the desulfurization process and installing an alkaline washing tower before the carbon capture system. However, due to the large amount of coal-fired flue gas, SO2 will inevitably accumulate gradually under long-term operation conditions, leading to absorbent poisoning and deactivation. The activated carbon adsorption process utilizes the adsorption characteristics of activated carbon for Fe ions to reduce the Fe content in the absorbent. However, the functional sites of traditional activated carbon are single and are easily affected by other substances in the absorbent, such as heat-stable salts and organic components, making it impossible to achieve efficient and rapid Fe ion removal. The above methods still have certain defects in improving the poisoning effect of SO2 and Fe ion impurities on the absorbent. From the current research point of view, developing bifunctional catalytic materials with catalytic activity and adsorption activity, utilizing catalytic sites to catalytically crack thermally stable sulfate to desorb SO2 and release amine active sites, and utilizing adsorption sites to remove Fe ions, is an effective way to simultaneously improve the stable operation of carbon capture absorbents.

[0004] Transition metal-modified acid catalysts can reduce the energy barrier of the absorbent's regeneration reaction. At the same time, by functionalizing the catalyst, using transition metal-modified acid catalysts to regenerate sulfur-poisoned absorbents and remove Fe ions is currently an effective means of improving absorbent stability. Patent CN116747857A proposes a catalytic regeneration material for sulfur-resistant carbon capture amine absorbents, as well as its preparation method and use. The regeneration of sulfur-poisoned absorbents is achieved by utilizing a core-shell Mn3O4 material. The paper (Sep. Purif. Technol. 2025, 362: 131607) proposes a sepiolite-modified Zr-Sep catalyst for efficient Fe ion removal from the absorbent. These research results demonstrate that the use of acid catalysts can achieve regeneration of poisoned absorbents and removal of Fe ions, improving absorbent operational stability. However, the metals in the above acid catalysts exist in the form of oxides or supports. Under the strong alkaline etching of the absorbent, the catalytic active sites will gradually deactivate and the catalyst stability is poor. In addition, the carriers mainly composed of metal oxides and sepiolite have small porosity and low activity.

[0005] Therefore, how to provide an efficient multifunctional catalyst for the regeneration of sulfur-poisoned absorbent and the Fe ion removal process in the carbon capture process is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention proposes a multifunctional catalyst for regeneration of carbon capture absorbent, and a preparation method and application thereof.

[0007] To achieve the above objectives, the present invention provides the following technical solutions:

[0008] A method for preparing a multifunctional catalyst for regenerating a carbon capture absorbent comprises the following steps:

[0009] The multifunctional catalyst is obtained by mixing a mixed solution of cobalt salt and inorganic transition metal salt with a 2-methylimidazole solution, performing a hydrothermal reaction, and then performing a heat treatment on the product of the hydrothermal reaction.

[0010] Beneficial effect: The present invention mixes cobalt and different transition metal salts. The introduction of transition metals (Mn / Fe / Ni / Zr) changes the electron cloud distribution of Co through d orbital hybridization, thereby enhancing the activation ability of CO2.

[0011] Preferably, the molar ratio of the cobalt element in the cobalt salt to the metal element M in the transition metal salt is 1:(0.2-0.5).

[0012] More preferably, the molar ratio of the cobalt element in the cobalt salt to 2-methylimidazole is (1-1.5):(1-1.5).

[0013] Beneficial effects: 2-methylimidazole is both a ligand and a structure-directing agent. When the molar ratio of cobalt in the cobalt salt to 2-methylimidazole is 1:1, a standard ZIF-67 dodecahedral structure is formed; when the molar ratio of cobalt in the cobalt salt to 2-methylimidazole is 1.5:1, the excess Co 2+ It can induce the formation of surface defect sites and increase the surface area.

[0014] More preferably, in the mixed solution, the concentration of the cobalt salt is 0.6-1.5 mmol / mL, and the concentration of the inorganic transition metal salt is 0.1-0.5 mmol / mL.

[0015] The concentration of the 2-methylimidazole solution is 0.3-0.75 mmol / mL.

[0016] Beneficial effects: The diffusion rate of cobalt ions is accelerated at high concentrations, shortening the nucleation induction period. However, concentrations greater than 1.5 mmol / mL can lead to particle agglomeration. The low concentration region of transition metal salts (0.1-0.5 mmol / mL) ensures uniform doping of heterogeneous atoms.

[0017] Preferably, the cobalt salt is one or more of cobalt nitrate, cobalt sulfate, cobalt carbonate and cobalt acetate.

[0018] More preferably, the cobalt nitrate is cobalt nitrate hexahydrate.

[0019] Preferably, the inorganic transition metal salt is a soluble metal salt, and the inorganic transition metal salt is one or more of manganese salt, iron salt, nickel salt and zirconium salt.

[0020] Optionally, the manganese salt is selected from manganese nitrate or manganese chloride; the iron salt is selected from iron sulfate, iron nitrate or iron chloride; the nickel salt includes nickel nitrate; and the zirconium salt includes zirconium nitrate.

[0021] Preferably, the temperature of the hydrothermal reaction is 120-150° C., and the time is 10-12 h.

[0022] Beneficial effects: When the reaction temperature is less than 120°C, the MOF crystallinity is insufficient, and the reaction temperature greater than 150°C leads to the decomposition of the organic ligand.

[0023] Preferably, the heat treatment temperature is 450-500° C. and the time is 1-2 hours.

[0024] Beneficial effects: At the above calcination temperature, the MOF skeleton is carbonized to generate a graphitized carbon layer, while the metal node is converted into a CoO heterojunction. At the same time, the carbon layer coating effectively inhibits metal sintering.

[0025] The present invention also provides a multifunctional catalyst prepared by the above preparation method.

[0026] Preferably, the multifunctional catalyst is a sphere assembled from a layered structure, and transition metal nanoparticles are attached to the surface of the layered structure, with a specific surface area greater than 20 m 2 / g.

[0027] Beneficial effects: The lamellar structure is beneficial to increasing the specific surface area of the catalyst and providing sufficient sites for the attachment of transition metal nanoparticles.

[0028] More preferably, the thickness of the sheet structure is 100 to 200 nm, and has a multi-level pore structure of metal-NC coordination;

[0029] The diameter of the sphere is 30 to 50 μm.

[0030] The size of the transition metal nanoparticle structure is 200-500 nm, and it is a metal oxide structure.

[0031] A multifunctional catalyst for the regeneration of sulfur-poisoned absorbent and the removal of Fe ions in carbon capture processes.

[0032] Beneficial effects: The multifunctional catalyst provided by the present invention can catalyze the cracking of the heat-stable sulfate formed by the absorbent and SO2, and has a large specific surface area and can adsorb Fe impurities.

[0033] Compared with the prior art, the present invention has the following advantages and technical effects:

[0034] The preparation method provided by the present invention can obtain a spherical multifunctional catalyst formed by stacking a layer structure, and the cobalt element in the catalyst is mainly present in the layer structure in the form of cobalt-nitrogen-carbon coordination. Part of the cobalt and other metals in the present invention are present on the surface of the layer structure in the form of metal oxides. The strong interaction between the two makes the multifunctional catalyst have strong stability. In addition, the multifunctional catalyst obtained by the present invention has a high specific surface area, greater than 20m 2 / g, the absorbed CO2 absorption and desorption cycle loading can be increased by 28.9-68.6%, achieving active regeneration of SO2-poisoned absorbents. Furthermore, the multifunctional catalyst prepared by the present invention can remove Fe ions from the absorbent, with a removal rate of up to 60-80%. Finally, the preparation method provided by the present invention is simple and easy to operate, making it easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0036] Figure 1 This is a SEM image of the multifunctional catalyst obtained in Example 2;

[0037] Among them, (a) is the magnification Mag is 170X; (b) is the magnification Mag is 1k X; (c) is the magnification Mag is 5k X; (d) is the magnification Mag is 50k X;

[0038] Figure 2 is a N2 adsorption-desorption curve of the MnCo-0.3 / ZIF-67 catalyst obtained in Example 2;

[0039] Figure 3 is the XRD curve of the MnCo-0.3 / ZIF-67 catalyst obtained in Example 2;

[0040] Figure 4 is the FT-IR curve of the MnCo-0.3 / ZIF-67 catalyst obtained in Example 2;

[0041] Figure 5 The effect of the MnCo-x / ZIF-67 catalysts obtained in Examples 1-3 and Comparative Examples 1-2 on the CO2 desorption activity of the SO2-poisoned ethanolamine absorbent;

[0042] Figure 6 The effect of the MnCo-0.3 / ZIF-67 catalyst obtained in Example 2 on the CO2 cycle loading of the SO2-poisoned ethanolamine absorbent;

[0043] Figure 7 The removal efficiency of Fe ions by the MnCo-0.3 / ZIF-67 catalyst obtained in Example 2. DETAILED DESCRIPTION

[0044] 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.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0047] Unless otherwise specified, room temperature or normal temperature in the embodiments of the present invention refers to 25±3°C.

[0048] Example 1

[0049] A method for preparing a multifunctional catalyst for improving the stability of a carbon capture absorbent comprises the following steps:

[0050] 0.01 mol of inorganic cobalt salt (cobalt nitrate hexahydrate) and 0.005 mol of inorganic transition metal salt (manganese nitrate tetrahydrate) were added to 10 mL of deionized water and stirred until dissolved to obtain solution A. 0.015 mol of 2-methylimidazole was added to 20 mL of deionized water to obtain solution B. Solution B was then slowly added to solution A. After stirring for 10 minutes, the solution was transferred to a polytetrafluoroethylene reactor and heated at 150°C for 12 hours. After the reaction was completed, it was cooled to room temperature and filtered. The obtained solid was dried at 60°C for 12 hours, placed in a nitrogen atmosphere and heated to 500°C for heat treatment for 2 hours to obtain a multifunctional catalyst named MnCo-0.5 / ZIF-67.

[0051] Example 2

[0052] A method for preparing a multifunctional catalyst for improving the stability of a carbon capture absorbent comprises the following steps:

[0053] 0.01 mol of inorganic cobalt salt (cobalt nitrate hexahydrate) and 0.003 mol of inorganic transition metal salt (manganese nitrate tetrahydrate) were added to 10 mL of deionized water and stirred until dissolved to obtain solution A. 0.015 mol of 2-methylimidazole was added to 20 mL of deionized water to obtain solution B. Solution B was then slowly added to solution A. After stirring for 10 minutes, the solution was transferred to a polytetrafluoroethylene reactor and heated at 150°C for 12 hours. After the reaction was completed, it was cooled to room temperature and filtered. The obtained solid was dried at 60°C for 12 hours, placed in a nitrogen atmosphere and heated to 500°C for heat treatment for 2 hours to obtain a multifunctional catalyst named MnCo-0.3 / ZIF-67.

[0054] Example 3

[0055] A method for preparing a multifunctional catalyst for improving the stability of a carbon capture absorbent comprises the following steps:

[0056] 0.01 mol of inorganic cobalt salt (cobalt nitrate hexahydrate) and 0.002 mol of inorganic transition metal salt (manganese nitrate tetrahydrate) were added to 10 mL of deionized water and stirred until dissolved to obtain solution A. 0.015 mol of 2-methylimidazole was added to 20 mL of deionized water to obtain solution B. Solution B was then slowly added to solution A. After stirring for 10 minutes, the solution was transferred to a polytetrafluoroethylene reactor and heated at 150°C for 12 hours. After the reaction was completed, it was cooled to room temperature and filtered. The obtained solid was dried at 60°C for 12 hours, placed in a nitrogen atmosphere and heated to 500°C for heat treatment for 2 hours to obtain a multifunctional catalyst named MnCo-0.2 / ZIF-67.

[0057] Example 4

[0058] A method for preparing a multifunctional catalyst for improving the stability of a carbon capture absorbent is provided. The method differs from Example 2 only in that the manganese salt is replaced with an iron salt (ferric nitrate nonahydrate) of equal molar mass. The remaining process steps and parameters are the same as those of Example 2.

[0059] Example 5

[0060] A method for preparing a multifunctional catalyst for improving the stability of a carbon capture absorbent is provided. The method differs from Example 2 only in that the manganese salt is replaced with an equimolar nickel salt (nickel nitrate hexahydrate). The remaining process steps and parameters are the same as those in Example 2.

[0061] Example 6

[0062] A method for preparing a multifunctional catalyst for improving the stability of a carbon capture absorbent is provided. The method differs from Example 2 only in that the manganese salt is replaced with a zirconium salt (zirconium nitrate pentahydrate) of equal molar mass. The remaining process steps and parameters are the same as those in Example 2.

[0063] Comparative Example 1

[0064] A method for preparing a multifunctional catalyst, which differs from Example 2 only in that an inorganic transition metal manganese salt is not included, that is, the method comprises the following steps:

[0065] 0.01 mol of inorganic cobalt salt (cobalt nitrate hexahydrate) was added to 10 mL of deionized water and stirred until dissolved to obtain solution A. 0.015 mol of 2-methylimidazole was added to 20 mL of deionized water to obtain solution B. Solution B was then slowly added to solution A. After stirring for 10 minutes, the solution was transferred to a polytetrafluoroethylene reactor and heated at 150°C for 12 hours. After the reaction was completed, it was cooled to room temperature and filtered. The obtained solid was dried at 60°C for 12 hours, placed in a nitrogen atmosphere and heated to 500°C for heat treatment for 2 hours to obtain a multifunctional catalyst named Co / ZIF-67.

[0066] Comparative Example 2

[0067] A method for preparing a multifunctional catalyst (MnO2) differs from Example 2 only in that it does not include an inorganic transition metal cobalt salt, that is, it comprises the following steps:

[0068] 0.003 mol of inorganic transition metal salt (manganese nitrate tetrahydrate) was added to 10 mL of deionized water and stirred until dissolved to obtain solution A. 0.015 mol of 2-methylimidazole was added to 20 mL of deionized water to obtain solution B. Solution B was then slowly added to solution A. After stirring for 10 minutes, the mixture was heated to 50°C in an oil bath and continued to stir for 6 hours. The mixture was cooled and aged for 20 minutes. The resulting solid was then dried at 60°C for 12 hours, placed in a nitrogen atmosphere, heated to 500°C, and heat treated for 2 hours to obtain a multifunctional catalyst MnO2.

[0069] Technical effect:

[0070] 1. Material structure analysis:

[0071] Taking the MnCo-0.3 / ZIF-67 catalyst obtained in Example 2 as an example, the structure of the MnCo-0.3 / ZIF-67 catalyst was analyzed by SEM, N2 adsorption and desorption, XRD and FT-IR. The test results are as follows: Figure 1-4 shown.

[0072] like Figure 1 SEM images at different magnifications show that the MnCo-0.3 / ZIF-67 catalyst is a spherical structure with a size of 30 to 50 μm. The spherical structure is composed of a stack of 100 to 200 nm thick lamellar structures, and nanoparticles with a size of 200 to 500 nm adhere to the surface of the lamellar structures. SEM results show that due to the stacking of the lamellar structure, the catalyst has a high porosity and specific surface area, which helps the mass transfer of reactants and improves the reaction efficiency. Figure 2 The N2 adsorption-desorption curves further demonstrate that the prepared MnCo-0.3 / ZIF-67 catalyst has a higher specific surface area and mesopore diameter than metal oxides, which are 24.592 m 2 / g and 19.86nm, which is conducive to the mass transfer of reactants and has a high porosity (0.12cm 3 / g).

[0073] like Figure 3 As shown in the XRD curve of the catalyst, a clear characteristic peak of carbon material can be observed at the 26° position. Therefore, in the MnCo-0.3 / ZIF-67 catalyst prepared by the present invention, Co is mainly dispersed in the catalyst in the form of cobalt-nitrogen-carbon (Co-NC). The Co-NC structure can provide the catalyst with a large number of unsaturated metal centers as acid sites, thereby improving the CO2 desorption activity of the catalyst. Part of the cobalt element exists in the form of CoO on the surface of the Co-NC layer structure, and the Mn element mainly exists in the form of MnO2, which can be used as a regeneration effect of the SO2 poisoning absorbent. In addition, by Figure 4From the FT-IR curves, it can be seen that there are abundant -OH functional groups on the surfaces of Co-NC and MnO2 structures, which can serve as adsorption sites to efficiently capture Fe ions.

[0074] 2.CO2 catalytic desorption test:

[0075] The CO2 desorption capacity of SO2 poisoned absorbent was tested using MnCo-x / ZIF-67 catalysts with different Mn doping ratios (catalysts obtained in Examples 1-3 and Comparative Examples 1-2). Specifically, a simulated flue gas containing 12% (volume concentration) CO2 and 0-1000ppm SO2 was first passed into a 150mL ethanolamine solution to prepare a SO2 poisoned absorbent. Then, a catalyst accounting for 0.1wt.% of the saturated liquid mass fraction was added, and the absorbent liquid was heated to 90°C to examine the CO2 catalytic desorption performance of the catalyst on the SO2 poisoned absorbent. The results of CO2 desorption capacity under different conditions are shown in FIG. Figure 5 As shown, Co / ZIF-67 is the catalyst obtained in Comparative Example 1, and MnO2 is the catalyst obtained in Comparative Example 2.

[0076] Depend on Figure 5 It can be seen that compared with the blank (non-catalytic) conditions, the addition of the catalyst prepared in the present invention can improve the CO2 desorption capacity of the absorbent, and in the presence of SO2, the doping of the Mn element significantly improves the CO2 desorption amount of the absorbent, indicating that the Mn element is a key component for achieving the regeneration of the SO2 poisoned absorbent. However, when the doping amount of the Mn component is too much, it will cause the lamellar structure to be converted into a nanoparticle structure, thereby making it impossible to prepare a spherical catalyst with a high specific surface area and porosity, which will lead to a decrease in performance. Therefore, the molar ratio of Mn and other transition metal salts and inorganic cobalt salts in the present invention should be controlled at 0.2-0.5 to achieve a higher catalytic desorption activity.

[0077] 3.CO2 catalytic cycle loading test:

[0078] The effect of the MnCo-0.3 / ZIF-67 catalyst obtained in Example 2 on the CO2 cycling capacity was further evaluated under the action of 100 ppm SO2. Specifically, the absorbent was 150 mL of ethanolamine solution, the initial CO2 loading was 2.48 mol / L, the reaction temperature was 90°C, and the reaction time was 30 min. The results are shown in Figure 2. Figure 6 shown.

[0079] It can be seen that the MnCo-0.3 / ZIF-67 catalytic material of the present invention has the best activity. The temperature at which CO2 desorption begins can be reduced from 70.2°C to 60.7°C, and the desorption energy barrier is greatly reduced. In addition, the catalyst greatly increases the CO2 desorption amount of the SO2-poisoned ethanolamine absorbent, realizing the active regeneration of the SO2-poisoned absorbent, and the CO2 circulation load is increased from the non-catalytic 0.334 mol / L to 0.563 mol / L, an increase of about 68.6%.

[0080] 4.Fe ion removal performance test:

[0081] The Fe ion removal test in the absorbent was conducted using MnCo-0.3 / ZIF-67 multifunctional catalyst. Specifically, the Fe ion concentration in the initial test solution was 32.7 ppm. The Fe ion concentration in the absorbent within 11 minutes of the test was as follows: Figure 7 shown.

[0082] Depend on Figure 7 It can be seen that within 2 minutes, the MnCo-0.3 / ZIF-67 multifunctional catalyst can reduce the Fe ion concentration of the absorbent from 32.7 ppm to 10.3 ppm, achieving an Fe ion removal effect of 68.5%, indicating that the catalyst of the present invention also has strong adsorption performance for Fe ions, and can achieve efficient and synchronous removal of impurity Fe ions.

[0083] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for preparing a multifunctional catalyst for regenerating a carbon capture absorbent, characterized in that: The following steps are involved: The multifunctional catalyst is obtained by mixing a mixed solution of cobalt salt and inorganic transition metal salt with a 2-methylimidazole solution, performing a hydrothermal reaction, and then performing a heat treatment on the product of the hydrothermal reaction.

2. The method for preparing a multifunctional catalyst for regeneration of carbon capture absorbent according to claim 1, characterized in that: The molar ratio of the cobalt element in the cobalt salt to the metal element M in the transition metal salt is 1:(0.2-0.5).

3. The method for preparing a multifunctional catalyst for regeneration of carbon capture absorbent according to claim 1, characterized in that: The cobalt salt is selected from one or more of cobalt nitrate, cobalt sulfate, cobalt carbonate and cobalt acetate.

4. The method for preparing a multifunctional catalyst for regeneration of carbon capture absorbent according to claim 1, characterized in that: The inorganic transition metal salt is selected from one or more of manganese salts, iron salts, nickel salts and zirconium salts.

5. The method for preparing a multifunctional catalyst for regeneration of carbon capture absorbent according to claim 4, characterized in that: The manganese salt is selected from manganese nitrate or manganese chloride; The iron salt is selected from ferric sulfate, ferric nitrate or ferric chloride; The nickel salt is selected from nickel nitrate; The zirconium salt is selected from zirconium nitrate.

6. The method for preparing a multifunctional catalyst for regeneration of carbon capture absorbent according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 120-150° C., and the time is 10-12 hours.

7. The method for preparing a multifunctional catalyst for regeneration of carbon capture absorbent according to claim 1, characterized in that: The heat treatment temperature is 450-500° C. and the time is 1-2 hours.

8. A multifunctional catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. The multifunctional catalyst according to claim 8, characterized in that The multifunctional catalyst is a sphere assembled from a layered structure, and transition metal nanoparticles are attached to the surface of the layered structure.

10. Use of the multifunctional catalyst according to claim 8 or 9 in regenerating a sulfur-poisoned absorbent and removing Fe ions in a carbon capture process.

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