An adsorbent, its preparation method and application, and a method for carbon dioxide hydration adsorption

Abstract

The present invention belongs to the field of carbon dioxide capture, and relates to an adsorbent, a preparation method and application thereof, and a method for carbon dioxide hydration adsorption. The preparation method of the adsorbent comprises the following steps: S1. Hydrothermally reacting graphene oxide and a nitrogen-containing compound in water, and the conditions of the hydrothermal reaction enable the graphene oxide to be nitrogen-doped and cut into quantum dots to obtain nitrogen-doped graphene oxide quantum dots; S2. Mixing the nitrogen-doped graphene oxide quantum dots, tetrabutylammonium fluoride and cyclopentane to obtain the adsorbent. The key of the present invention lies in using a nitrogen-containing compound as a cutting agent and a doping agent to prepare graphene oxide quantum dots. On this basis, the obtained nitrogen-doped graphene oxide quantum dots are used in combination with tetrabutylammonium fluoride and cyclopentane as a carbon dioxide hydration adsorbent, which can effectively improve the separation efficiency of carbon dioxide.

Description

Technical Field

[0001] The present invention belongs to the field of carbon dioxide capture, and particularly relates to an adsorbent, a preparation method and application thereof, and a method for carbon dioxide hydration adsorption. Background Art

[0002] Hydrate-based carbon dioxide capture is a technology that can rapidly capture carbon dioxide gas through hydrate formation under mild conditions, and can also release the captured carbon dioxide gas through hydrate decomposition. The successful practical application of this technology is hindered by some technical difficulties in hydrate formation, such as insufficient storage capacity and slow formation rate.

[0003] Currently, methods for accelerating hydrate formation include physical methods and chemical methods. Physical methods include stirring, bubbling, atomization and external field methods, the purpose of which is to expand the contact area between the gas and liquid phases in the hydrate formation process, enhance the heat and mass transfer of hydrates, and thus accelerate the formation rate of hydrates. Chemical methods can be divided into thermodynamic promotion and kinetic promotion. Thermodynamic promotion requires the use of thermodynamic promoters, aiming to reduce the hydrate phase equilibrium conditions and adjust the reaction conditions. Thermodynamic promoters usually include tetrahydrofuran (THF), tetrabutylammonium bromide (TBAB), acetone and gas additives, etc. Kinetic promotion requires the use of kinetic promoters, which are mainly surfactants and mainly play the role of reducing the liquid surface tension, reducing the diffusion resistance of gas molecules to the liquid phase, and increasing the solubility of gas molecules. Kinetic promoters include sodium dodecylbenzenesulfonate (SDBS), sodium dodecyl sulfate (SDS), etc. However, in the currently commonly used methods for accelerating hydrate formation, the separation efficiency of physical methods is low, and due to the complex equipment, additional energy is usually required, resulting in higher costs in industrial production; the separation efficiency of chemical methods is low, and the recovery rate of kinetic promoters such as surfactants used in the kinetic promotion process is low, and some surfactants are even toxic and harmful to the environment, which are restricted in practical applications. Summary of the Invention

[0004] The first object of the present invention is to provide a preparation method of an adsorbent capable of improving the carbon dioxide separation efficiency.

[0005] Specifically, the preparation method of the adsorbent provided by the present invention includes the following steps:

[0006] S1. Hydrothermally react graphene oxide and a nitrogen-containing compound in water under hydrothermal reaction conditions such that the graphene oxide is nitrogen-doped and cut into quantum dots to obtain nitrogen-doped graphene oxide quantum dots;

[0007] S2. Mix the nitrogen-doped graphene oxide quantum dots, tetrabutylammonium fluoride and cyclopentane to obtain the adsorbent.

[0008] The second object of the present invention is to provide an adsorbent prepared by the above method.

[0009] The third object of the present invention is to provide the application of the above adsorbent as a carbon dioxide hydration adsorbent.

[0010] The fourth object of the present invention is to provide a method for carbon dioxide hydration adsorption, which includes subjecting a mixed gas containing carbon dioxide to a hydration adsorption treatment using the above adsorbent to capture carbon dioxide in the mixed gas.

[0011] The key of the present invention lies in preparing graphene oxide quantum dots using a nitrogen-containing compound as a cutting agent and a doping agent. On this basis, the obtained nitrogen-doped graphene oxide quantum dots are used in combination with tetrabutylammonium fluoride (TBAF) and cyclopentane (CP) as a carbon dioxide hydration adsorbent, which can effectively improve the separation efficiency of carbon dioxide. Presumably, the reasons are as follows: on the one hand, when preparing graphene oxide quantum dots using a nitrogen-containing compound as a cutting agent and a doping agent, nitrogen atoms can be effectively incorporated into the graphene oxide quantum dots. The introduction of nitrogen atoms can more effectively reduce the liquid surface tension, increase the solubility of gas molecules, improve the heat and mass transfer ability of the system, and shorten the induction time, thus better promoting the formation of hydrates; on the other hand, graphene quantum dots are nanoparticles, and the nanoparticles themselves can improve the thermal conductivity of the system, while the combined use of tetrabutylammonium fluoride and cyclopentane is conducive to the formation of a thermal conduction network of nanoparticles, thereby endowing the system with good heat and mass transfer ability and being more conducive to promoting the formation of hydrates. That is to say, the present invention synergistically promotes the synthesis of hydrates from both internal and external dimensions, thereby achieving the effective capture of carbon dioxide. Detailed implementation mode

[0012] The preparation method of the adsorbent provided by the present invention includes the following steps:

[0013] S1. Hydrothermally react graphene oxide and a nitrogen-containing compound in water under hydrothermal reaction conditions such that the graphene oxide is nitrogen-doped and cut into quantum dots to obtain nitrogen-doped graphene oxide quantum dots;

[0014] S2. Mix the nitrogen-doped graphene oxide quantum dots, tetrabutylammonium fluoride, and cyclopentane to obtain the adsorbent.

[0015] In the present invention, the hydrothermal reaction method in step S1 generally includes stirring and mixing graphene oxide, a nitrogen-containing compound and water evenly, and then reacting the obtained mixture under hydrothermal reaction conditions. Among them, the mixing method can be to first add graphene oxide into water and stir and mix, then add the nitrogen-containing compound and continue to stir and mix, or to first add the nitrogen-containing compound into water and stir and mix, then add graphene oxide and continue to stir and mix, or to add graphene oxide and the nitrogen-containing compound into water at the same time and stir and mix. The present invention synthesizes graphene oxide quantum dots by a one-step hydrothermal reaction, the required conditions are mild and controllable, and after the reaction, impurities are easy to remove and the yield is high. The nitrogen-doped graphene oxide quantum dots obtained by the hydrothermal reaction are a kind of tiny nanoparticles, the lateral size of which is generally below 100 nm, the longitudinal size is below a few nanometers, and it has a graphene structure of one or several layers, which are very small graphene fragments. The nitrogen-doped graphene oxide quantum dots have the inherent properties of graphene oxide, and due to their ultra-small size and chemical activity, they have potential application prospects in catalysis. Applying the nitrogen-doped graphene oxide quantum dots to the hydration adsorption of carbon dioxide can not only reduce the liquid surface tension and increase the solubility of gas molecules, but also improve the heat and mass transfer ability of the system, so as to achieve the effect of promoting the formation of hydrates and shortening the induction time.

[0016] In the present invention, the mass ratio of graphene oxide to the nitrogen-containing compound is preferably 10:(1-55). On the one hand, the nitrogen-containing compound is relatively mild, and graphene oxide quantum dots can be better prepared under this ratio. On the other hand, nitrogen doping under this ratio can further improve the affinity for carbon dioxide gas, enabling the gas to enter the liquid phase faster and in greater quantity during carbon capture in subsequent step S2, and thus having better carbon dioxide capture ability. The mass ratio of graphene oxide to the nitrogen-containing compound can specifically be 10:1, 10:5, 10:10, 10:15, 10:20, 10:25, 10:30, 10:35, 10:40, 10:45, 10:50 or any value therebetween. Graphene oxide (GO) is a carbon material with a layered structure, having excellent properties such as a large specific surface area and good dispersibility in water. At the same time, the surface of graphene oxide has abundant functional groups to endow it with good hydrophilicity and lipophilicity (amphiphilicity). The amphiphilic property of graphene oxide enables it to act as a surfactant and can also be used to promote hydrate formation. Graphene oxide has a layered structure, and the sheet diameter is preferably 10-200 μm, which can specifically be 10 nm, 30 nm, 50 nm, 80 nm, 100 nm, 120 nm, 150 nm, 180 nm, 200 nm or any value therebetween. The type of the nitrogen-containing compound is not particularly limited as long as it can be used as a cleavage agent to prepare graphene oxide quantum dots and can be used as a doping agent to improve the carbon dioxide separation efficiency. It is preferably ammonia water, urea or a mixture of ammonia water and urea, and particularly preferably ammonia water. In addition, when the dosage of the nitrogen-containing compound can just adjust the pH value of the hydrothermal reaction system to the target range, there is no need to additionally add other pH regulators to adjust the pH value.

[0017] In the present invention, the conditions of the hydrothermal reaction preferably include a temperature of 70-200 °C, such as 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, 200 °C or any value therebetween; a pH value of 10-12, such as 10, 10.5, 11, 11.5, 12 or any value therebetween; and a time of 3-10 h, such as 3 h, 4 h, 6 h, 8 h, 10 h or any value therebetween. In addition, in order to improve the efficiency and effect of the hydrothermal reaction, the conditions of the hydrothermal reaction are most preferably a temperature of 120-150 °C, a pH value of 10-12, and a time of 5-8 h.

[0018] In the present invention, the preparation method of the adsorbent provided by the present invention further includes a purification step after the hydrothermal reaction in step S1. The purification method only needs to be able to remove impurities in the hydrothermal product (such as unreacted graphene oxide and / or nitrogen-containing compounds), and there is no particular limitation. In a preferred embodiment, the purification method includes allowing the hydrothermal reaction product to stand and cool to room temperature, then centrifuging to collect the supernatant, heating the supernatant, and then performing dialysis separation using a dialysis bag with a molecular weight cut-off of 300 Da. After that, the obtained retentate is freeze-dried to obtain nitrogen-doped graphene oxide quantum dots. Among them, the rotation speed of centrifugation is preferably 9000 - 10000 rpm / min, such as 9000, 9200, 9400, 9600, 9800, 10000 rpm / min. The temperature of the heat treatment is preferably 40 - 120 °C, such as 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C or any value between them; the time is preferably 1 - 8 h, such as 1 h, 2 h, 4 h, 6 h, 8 h or any value between them. The main purpose of dialysis separation is to remove excess nitrogen-containing compounds.

[0019] In the present invention, in step S2, the ratio of nitrogen-doped graphene oxide quantum dots to tetrabutylammonium fluoride is preferably 100 mg : (0.3 - 2) mol, such as 100 mg : 0.3 mol, 100 mg : 0.5 mol, 100 mg : 0.8 mol, 100 mg : 1 mol, 100 mg : 1.2 mol, 100 mg : 1.5 mol, 100 mg : 1.8 mol, 100 mg : 2 mol or any value between them. The ratio of nitrogen-doped graphene oxide quantum dots to cyclopentane is preferably 100 mg : (1 - 10) mL, such as 100 mg : 1 mL, 100 mg : 2 mL, 100 mg : 4 mL, 100 mg : 6 mL, 100 mg : 8 mL, 100 mg : 10 mL or any value between them. In addition, the mixing of nitrogen-doped graphene oxide quantum dots, tetrabutylammonium fluoride and cyclopentane and their subsequent compound use can be carried out in the presence of water.

[0020] The present invention also provides an adsorbent prepared by the above method. This adsorbent can be used as a kinetic promoter for carbon dioxide hydration adsorption. Through the amphiphilic and nanoparticle characteristics of nitrogen-doped graphene oxide quantum dots and the compound action of nitrogen-doped graphene oxide quantum dots, tetrabutylammonium fluoride and cyclopentane, during the hydration adsorption process, it can not only reduce the liquid surface tension, increase the solubility of gas molecules, but also improve the mass transfer and heat transfer ability of the system, promote the formation of hydrates, and shorten the induction time.

[0021] The present invention also provides the application of the above adsorbent as a carbon dioxide hydration adsorbent.

[0022] The method for hydrate adsorption of carbon dioxide provided by the present invention includes subjecting the mixed gas containing carbon dioxide to hydrate adsorption treatment using the above-mentioned adsorbent to capture carbon dioxide in the mixed gas.

[0023] In the present invention, the process of hydrate adsorption treatment is not particularly limited as long as it can achieve the capture of carbon dioxide in the mixed gas. In a preferred embodiment, the process of hydrate adsorption treatment includes placing the hydrate adsorbent inside a hydrate adsorption reactor, pressurizing the inside of the hydrate adsorption reactor to above 0.2 MPa, then decompressing to remove the air present inside the hydrate adsorption reactor, pre-cooling the hydrate adsorbent placed inside the hydrate adsorption reactor to 2 - 5 °C, introducing the mixed gas until the pressure reaches above 2 MPa after the temperature reaches the pre-cooling temperature, stopping the introduction of the mixed gas, turning on the stirring during the gas introduction process, turning off the stirring when the pressure change amplitude inside the hydrate adsorption reactor drops below 0.01 MPa / min, continuing the reaction for 1 - 5 h after stopping the introduction of the mixed gas, and then opening the gas outlet valve to collect the remaining gas. In the present invention, the pressure refers to the gauge pressure.

[0024] In the present invention, the mixed gas is carbon dioxide and nitrogen. The volume ratio of carbon dioxide in the mixed gas is preferably 5 - 30%, such as 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30% or any value between them.

[0025] The present invention will be described in detail below through examples.

[0026] Example 1

[0027] S1. Mix 10 g of graphene oxide powder with 90 mL of ammonia water (concentration 28 wt%) and 410 mL of deionized water evenly in a glass beaker. Adjust the pH of the solution to about 12, stir for 30 min, transfer the mixture to a 1 L polytetrafluoroethylene-lined autoclave, heat it to 150 °C in an oven and keep it for 5 h for hydrothermal reaction. After the hydrothermal reaction is completed, let the reaction solution stand and cool to room temperature, and centrifuge and collect the supernatant at a rotation speed of 10000 rpm / min. Heat the supernatant to 100 °C for 1 h, and then perform dialysis using a dialysis bag with a molecular weight of 300 Da to remove the unreacted ammonia water. After dialysis is completed, subject the liquid on the retention side obtained to freeze-drying to obtain nitrogen-doped graphene oxide quantum dot powder.

[0028] S2. Dissolve the nitrogen-doped graphene oxide quantum dot powder, 0.3 mol% TBAF and 2.5% vol CP in 600 mL of water, with the addition amount of graphene oxide quantum dots being 50 mg / L. After the reaction solution is stirred and ultrasonically dispersed and mixed evenly for 20 min, an adsorbent is obtained.

[0029] Example 2

[0030] S1. Mix 10 g of graphene oxide powder, 1 g of urea and 500 mL of deionized water evenly in a glass beaker. Adjust the pH of the solution to about 12, stir for 30 min, transfer the mixture to a 1 L polytetrafluoroethylene-lined autoclave, heat it to 150 °C in an oven and keep it for 5 h for hydrothermal reaction. After the hydrothermal reaction is completed, let the reaction solution stand and cool to room temperature, centrifuge and collect the supernatant at a speed of 9000 rpm / min. Heat the supernatant to 40 °C for 8 h, and then dialyze it with a dialysis bag with a molecular weight of 300 Da to remove unreacted urea. After dialysis is completed, freeze-dry the liquid on the retentate side to obtain nitrogen-doped graphene oxide quantum dot powder.

[0031] S2. Dissolve the nitrogen-doped graphene oxide quantum dot powder, 0.3 mol% TBAF and 2.5% vol CP in 600 mL of water, where the addition amount of graphene oxide quantum dots is 50 mg / L. After the reaction solution is stirred and ultrasonically dispersed for 20 min to be evenly mixed, an adsorbent is obtained.

[0032] Example 3

[0033] S1. Mix 10 g of graphene oxide powder, 90 mL of ammonia water (concentration 28 wt%) and 410 mL of deionized water evenly in a glass beaker. Adjust the pH of the solution to about 12, stir for 30 min, transfer the mixture to a 1 L polytetrafluoroethylene-lined autoclave, heat it to 120 °C in an oven and keep it for 8 h for hydrothermal reaction. After the hydrothermal reaction is completed, let the reaction solution stand and cool to room temperature, centrifuge and collect the supernatant at a speed of 10000 rpm / min. Heat the supernatant to 70 °C for 8 h, and then dialyze it with a dialysis bag with a molecular weight of 300 Da to remove unreacted ammonia water. After dialysis is completed, freeze-dry the liquid on the retentate side to obtain nitrogen-doped graphene oxide quantum dot powder.

[0034] S2. Dissolve the nitrogen-doped graphene oxide quantum dot powder, 0.3 mol% TBAF and 2.5% vol CP in 600 mL of water, where the addition amount of graphene oxide quantum dots is 80 mg / L. After the reaction solution is stirred and ultrasonically dispersed for 20 min to be evenly mixed, an adsorbent is obtained.

[0035] Example 4

[0036] S1. Mix 10 g of graphene oxide powder with 1 g of urea and 500 mL of deionized water evenly in a glass beaker. Adjust the pH of the solution to about 10. After stirring for 30 min, transfer the mixture to a 1-L polytetrafluoroethylene-lined autoclave, heat it to 150 °C in an oven and keep it for 5 h for hydrothermal reaction. After the hydrothermal reaction is completed, let the reaction solution stand and cool to room temperature, and centrifuge at 9000 rpm / min to collect the supernatant. Heat the supernatant to 70 °C for 4 h, and then dialyze it with a dialysis bag with a molecular weight of 300 Da to remove unreacted urea. After dialysis is completed, freeze-dry the liquid on the retentate side to obtain nitrogen-doped graphene oxide quantum dot powder.

[0037] S2. Dissolve the nitrogen-doped graphene oxide quantum dot powder, 0.3 mol% TBAF and 2.5% vol CP in 600 mL of water, where the addition amount of graphene oxide quantum dots is 80 mg / L. After the reaction solution is stirred and ultrasonically dispersed for 20 min to be evenly mixed, an adsorbent is obtained.

[0038] Comparative Example 1

[0039] Prepare the adsorbent according to the method of Example 2, except that the preparation step of nitrogen-doped graphene oxide quantum dot powder is not included and nitrogen-doped graphene oxide quantum dot powder is not added to the adsorbent. Specifically, dissolve 0.3 mol% TBAF and 2.5% vol CP in 600 mL of water, and after stirring and ultrasonically dispersing for 20 min to be evenly mixed, a reference adsorbent is obtained.

[0040] Comparative Example 2

[0041] Prepare the adsorbent according to the method of Example 2, except that urea is not added during the preparation process of graphene oxide quantum dots, and the other conditions are the same as those in Example 2. The specific steps are as follows:

[0042] S1. Mix 10 g of graphene oxide powder and 500 mL of deionized water evenly in a glass beaker, then adjust the pH of the solution to 12 with sodium hydroxide, stir for 30 min, transfer the mixture to a 1-L polytetrafluoroethylene-lined autoclave, heat it to 150 °C in an oven and keep it for 5 h for hydrothermal reaction. After the hydrothermal reaction is completed, let the reaction solution stand and cool to room temperature, and centrifuge at 9000 rpm / min to collect the supernatant. Heat the supernatant to 40 °C for 8 h, and then dialyze it with a dialysis bag. After dialysis is completed, freeze-dry the liquid on the retentate side to obtain graphene oxide quantum dot powder.

[0043] S2. Dissolve graphene oxide quantum dot powder, 0.3 mol% TBAF, and 2.5 vol% CP in 600 mL of water, with the addition amount of graphene oxide quantum dots being 50 mg / L. After the reaction solution is stirred and ultrasonically dispersed for 20 min and mixed evenly, an adsorbent is obtained.

[0044] Comparative Example 3

[0045] Prepare the adsorbent according to the method of Example 2. The difference is that TBAF is replaced with CP of the same weight portion, and the other conditions are the same as those in Example 1, obtaining a reference adsorbent.

[0046] Comparative Example 4

[0047] Prepare the adsorbent according to the method of Example 2. The difference is that CP is replaced with TBAF of the same weight portion, and the other conditions are the same as those in Example 1, obtaining a reference adsorbent.

[0048] Test Example

[0049] Add the adsorbents obtained in each of the above examples and the reference adsorbents obtained in each of the comparative examples into the hydration adsorption reactor from the feeding port respectively. Pressurize the inside of the hydration adsorption reactor to 0.2 MPa, and then reduce the pressure to remove the initial air existing inside the hydration adsorption reactor. Use a circulating cooler to pre-cool the hydration adsorbent to 2 °C. After the temperature reaches the pre-cooling temperature, introduce a mixed gas until the pressure reaches 2 MPa, and then stop introducing the mixed gas. Turn on the stirrer during the gas introduction process and stir at a speed of 600 rpm / min. When the pressure change amplitude inside the hydration adsorption reactor drops below 0.01 MPa / min, turn off the stirrer, stop the reaction after 2 h, open the gas outlet valve to collect the remaining gas, and measure the contents of carbon dioxide and nitrogen in the remaining gas. Among them, the contents of carbon dioxide (CO 2 ) and nitrogen (N 2 ) in the initial mixed gas and the remaining gas, as well as the CO 2 separation efficiency are shown in Table 1. Among them, the CO 2 separation efficiency = (the amount of substance of CO 2 in the gas before the reaction - the amount of substance of CO 2 in the gas after the reaction) / the amount of substance of CO 2 in the gas before the reaction × 100%.

[0050] Table 1

[0051]

[0052] As can be seen from the results in Table 1, in the present invention, nitrogen-containing compounds are used as cutting agents and dopants to prepare graphene oxide quantum dots. On this basis, the obtained nitrogen-doped graphene oxide quantum dots are used in combination with tetrabutylammonium fluoride (TBAF) and cyclopentane (CP) as a carbon dioxide hydration adsorbent, which can effectively improve the separation efficiency of carbon dioxide.

[0053] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for preparing an adsorbent, characterized in that: The method comprises the following steps: S1. performing a hydrothermal reaction of graphene oxide and a nitrogen-containing compound in water, wherein the mass ratio of the graphene oxide to the nitrogen-containing compound is 10:(1-55), and the conditions of the hydrothermal reaction are such that the graphene oxide is doped with nitrogen and cut into quantum dots to obtain nitrogen-doped graphene oxide quantum dots; S2. The nitrogen-doped graphene oxide quantum dots, tetrabutylammonium fluoride and cyclopentane are mixed to obtain the adsorbent; the ratio of the nitrogen-doped graphene oxide quantum dots to tetrabutylammonium fluoride is 100 mg: (0.3~2) mol; the ratio of the nitrogen-doped graphene oxide quantum dots to cyclopentane is 100 mg: (1~10) mL.

2. The method for preparing an adsorbent according to claim 1, characterized in that: In step S1, the hydrothermal reaction comprises stirring and mixing the graphene oxide, the nitrogen-containing compound and water uniformly, and then reacting the obtained mixture under hydrothermal reaction conditions.

3. The method for preparing an adsorbent according to claim 1, characterized in that: In step S1, the graphene oxide has a layered structure, and the sheet diameter is 10-200 μm.

4. The method for preparing an adsorbent according to claim 1, characterized in that: In step S1, the nitrogen-containing compound is ammonia water and / or urea.

5. The method for preparing an adsorbent according to claim 1, characterized in that: In step S1, the hydrothermal reaction conditions include a temperature of 70-200° C., a pH value of 10-12, and a time of 3-10 h.

6. The method for preparing an adsorbent according to any one of claims 1 to 5, characterized in that: The method further comprises a purification step after the hydrothermal reaction in step S1.

7. The method for preparing an adsorbent according to claim 6, characterized in that: The purification method comprises cooling the hydrothermal reaction product to room temperature and then centrifuging and collecting the supernatant, heating the supernatant and then dialyzing it using a dialysis bag with a molecular weight cutoff of 300 Da, and then freeze-drying the obtained retentate to obtain nitrogen-doped graphene oxide quantum dots.

8. The method for preparing an adsorbent according to claim 7, characterized in that: The rotation speed of the centrifugal separation is 9000-10000 rpm / min.

9. The method for preparing an adsorbent according to claim 7, characterized in that: The conditions of the heating treatment include a temperature of 40-120° C. and a time of 1-8 hours.

10. An adsorbent prepared by the method according to any one of claims 1 to 9.

11. Use of the adsorbent according to claim 10 as a carbon dioxide hydration adsorbent.

12. A method for carbon dioxide hydration adsorption, characterized in that: The method comprises subjecting a mixed gas containing carbon dioxide to a hydration adsorption treatment using the adsorbent described in claim 10 to capture the carbon dioxide in the mixed gas.

13. The method for carbon dioxide hydration adsorption according to claim 12, characterized in that: The hydration adsorption treatment process includes placing a hydrated adsorbent inside a hydration adsorption reactor, pressurizing the inside of the hydration adsorption reactor to above 0.2 MPa, and then reducing the pressure to remove the air inside the hydration adsorption reactor, precooling the hydrated adsorbent placed inside the hydration adsorption reactor to 2-5°C, introducing a mixed gas after the temperature reaches the precooling temperature until the pressure reaches above 2 MPa, then stopping the introduction of the mixed gas, turning on stirring during the ventilation process, turning off stirring when the pressure change amplitude inside the hydration adsorption reactor drops below 0.01 MPa / min, continuing the reaction for 1-5 hours after stopping the introduction of the mixed gas, and then opening the gas outlet valve to collect the remaining gas.

14. The method for carbon dioxide hydration adsorption according to claim 13, characterized in that: The mixed gas is carbon dioxide and nitrogen.

15. The method for carbon dioxide hydration adsorption according to claim 13, characterized in that: The volume proportion of carbon dioxide in the mixed gas is 5-30%.

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