Method for removing trace amounts of water from carbon dioxide

Abstract

The application discloses a method for removing trace water from carbon dioxide, which comprises the following steps: firstly, mixing tetrapropylammonium hydroxide and deionized water uniformly to obtain solution A; dissolving potassium aluminate in the solution A to obtain solution B; adding tetraethyl orthosilicate into the solution B drop by drop, stirring and mixing; transferring the solution C into a hydrothermal kettle to react for at least 2 hours; after the reaction is completed, taking out the reaction product, washing with water, centrifugal separation and drying; continuously heating to 550 DEG C, calcining for at least 2 hours to obtain K-ZSM-5; preparing an ethanol solution of potassium ethoxide, immersing the K-ZSM-5 in the ethanol solution of potassium ethoxide, removing ethanol from the immersed K-ZSM-5 under vacuum, and obtaining an adsorbent; filling the adsorbent into an adsorption column, passing carbon dioxide into the adsorption column, and removing water in the carbon dioxide by using a chemical adsorption method. The preparation method of the adsorbent is simple, the material is easy to obtain, the whole impurity removal stage does not need high temperature, the impurity removal method is simple, the efficiency is relatively high, and the water content can be reduced to below 20 ppb.

Description

Technical Field

[0001] This invention relates to the field of specialty gas purification technology, specifically to a method for removing trace amounts of moisture from carbon dioxide. Background Technology

[0002] Due to its extremely low surface tension, scCO2 will not cause damage when cleaning precision electronic components. After cleaning or etching, simply releasing the pressure allows the CO2 to evaporate from the microporous structure without leaving any residue, achieving simultaneous etching, cleaning, and drying. Furthermore, CO2 is inexpensive, readily available, non-toxic, chemically stable, and non-flammable; therefore, it is considered a safe and environmentally friendly cleaning medium.

[0003] CO2 is a nonpolar solvent with a zero dipole moment. Therefore, CO2 can effectively remove nonpolar and weakly polar organic contaminants from wafers, such as silicones, aliphatic hydrocarbons with few carbon atoms, and oils. The physicochemical properties of scCO2 near its critical point, such as viscosity, diffusion coefficient, and solubility, are highly sensitive to changes in temperature and pressure. Based on these characteristics, the solubility of some contaminants on the wafer in the scCO2 medium can be controlled by adjusting temperature and pressure. By reducing pressure, CO2 can carry away the contaminants, achieving the purpose of cleaning the wafer. However, the solubility of polar substances on wafers in the scCO2 medium is low, usually requiring the addition of co-solvents, such as propylene carbonate, acetylacetone, and acetic acid, to increase their solubility and achieve the cleaning purpose. When scCO2 is used as a cleaning agent, the water content is critical, needing to be below 50 ppb. However, conventional adsorption and distillation methods often struggle to achieve this level of moisture content.

[0004] In response, this application provides a method for removing trace amounts of moisture from carbon dioxide, which effectively reduces the moisture content in carbon dioxide to 20 ppb through chemical adsorption, making it suitable for wafer cleaning and selective etching, and thus has practical significance. Summary of the Invention

[0005] The purpose of this invention is to provide a method for removing trace amounts of moisture from carbon dioxide. This method involves preparing an adsorbent and filling it into an adsorption column to effectively reduce the moisture content in carbon dioxide through chemical adsorption.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a method for removing trace amounts of moisture from carbon dioxide, comprising the following steps:

[0007] Preparation of S1 and K-ZSM-5: First, mix tetrapropylammonium hydroxide and deionized water evenly to obtain solution A; dissolve potassium aluminate in solution A to obtain solution B; add tetraethyl orthosilicate dropwise to solution B, stir and mix; transfer solution C to a hydrothermal reactor and react for at least 2 hours. After the reaction is complete, remove the reactants, wash with water, centrifuge, and dry; continue heating to 550℃ and calcine for at least 2 hours to obtain K-ZSM-5.

[0008] S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide, immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide, and remove the ethanol from the immersed K-ZSM-5 under vacuum to obtain the adsorbent.

[0009] S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove water from the carbon dioxide by chemical adsorption.

[0010] Preferably, in step S1, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:25 to 100.

[0011] Preferably, in step S1, the amount of potassium aluminate added is 0.005 mol to 0.02 mol, and the amount of tetraethyl orthosilicate added is 1 mol.

[0012] Preferably, in step S1, the mass ratio of tetrapropylammonium hydroxide to deionized water is 1:1 to 4:1.

[0013] Preferably, in step S1, the specific preparation method of solution C is to add tetraethyl orthosilicate dropwise to solution B at a rate of 1 mL / min, while stirring in an ice-water bath during the process. After the dropwise addition is completed, stirring is continued for 2 hours to obtain solution C.

[0014] Preferably, in step S1, the temperature of the hydrothermal reaction in the hydrothermal reactor is 150℃~190℃, and the hydrothermal reaction time is 12h~36h.

[0015] Preferably, in step S1, the specific method of calcination is as follows: continue heating at a heating rate of 1℃ / min, and calcine at 550℃ for 6 hours.

[0016] Preferably, in step S2, the concentration of potassium ethoxide in the ethanol solution is 6% to 24%.

[0017] Preferably, in step S3, the carbon dioxide introduced into the adsorption column is carbon dioxide that has been adsorbed by a 5A molecular sieve and has a moisture content of 1 ppm.

[0018] Preferably, in step S3, the carbon dioxide gas is used at a concentration of 200 h⁻¹ -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

[0019] In the above text, when the moisture content of the carbon dioxide after passing through the adsorption column is less than 50 ppb, the adsorption is considered complete.

[0020] The principle by which the prepared adsorbent can absorb water, as described above, is that the microporous structure of ZSM-5 can adsorb water; potassium ethoxide can react with water to produce potassium hydroxide and ethanol, and the ethanol can be adsorbed by the microporous structure of ZSM-5.

[0021] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0022] 1. This invention prepares an adsorbent by reacting tetrapropylammonium hydroxide, potassium aluminate and tetraethyl orthosilicate, and by controlling the raw material ratio and hydrothermal reaction conditions, it can reduce the moisture content in carbon dioxide through chemical adsorption to below 20 ppb, thus ensuring the application of critical carbon dioxide medium in wafer cleaning and selective etching.

[0023] 2. The adsorbent preparation method disclosed in this invention is simple, the materials are readily available, the entire impurity removal stage does not require high temperature, the impurity removal method is simple and efficient, and it is suitable for promotion and use. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] This embodiment relates to a method for removing trace amounts of moisture from carbon dioxide, and the specific method includes the following steps:

[0027] Preparation of S1 and K-ZSM-5: First, mix 200g of tetrapropylammonium hydroxide and 50g of deionized water evenly to obtain solution A; dissolve 0.49g of potassium aluminate in solution A to obtain solution B; add 104g of tetraethyl orthosilicate dropwise to solution B at a rate of 1mL / min, stirring in an ice-water bath during the process. After the dropwise addition is complete, continue stirring for 2 hours to obtain mixed solution C; transfer mixed solution C to a 300mL hydrothermal reactor and incubate at 170℃ for 24 hours; after the reaction is complete, remove the reactants, wash with water, centrifuge, and dry at 100℃; calcine at 550℃ for 6 hours at a rate of 1℃ / min to obtain K-ZSM-5;

[0028] S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide with a concentration of 24%. Immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide. Remove the ethanol from the immersed K-ZSM-5 under vacuum at 70°C to obtain the adsorbent.

[0029] S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove water from the carbon dioxide by chemical adsorption.

[0030] In step S1 above, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:100.

[0031] In the above text, the carbon dioxide introduced into the adsorption column is the carbon dioxide after it has been adsorbed by 5A molecular sieve, and the moisture content is 1 ppm.

[0032] Preferably, in step S3, the carbon dioxide gas is used at a concentration of 200 h⁻¹ -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

[0033] Example 2

[0034] This embodiment relates to a method for removing trace amounts of moisture from carbon dioxide, and the specific method includes the following steps:

[0035] Preparation of S1 and K-ZSM-5: First, mix 200g of tetrapropylammonium hydroxide and 50g of deionized water evenly to obtain solution A; dissolve 0.98g of potassium aluminate in solution A to obtain solution B; add 104g of tetraethyl orthosilicate dropwise to solution B at a rate of 1mL / min, stirring in an ice-water bath during the process. After the dropwise addition is complete, continue stirring for 2 hours to obtain mixed solution C; transfer mixed solution C to a 300mL hydrothermal reactor and incubate at 170℃ for 24 hours; after the reaction is complete, remove the reactants, wash with water, centrifuge, and dry at 100℃; calcine at 550℃ for 6 hours at a rate of 1℃ / min to obtain K-ZSM-5;

[0036] S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide with a concentration of 24%. Immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide. Remove the ethanol from the immersed K-ZSM-5 under vacuum at 70°C to obtain the adsorbent.

[0037] S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove water from the carbon dioxide by chemical adsorption.

[0038] In step S1 above, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:50.

[0039] In the above text, the carbon dioxide introduced into the adsorption column is the carbon dioxide after it has been adsorbed by 5A molecular sieve, and the moisture content is 1 ppm.

[0040] Preferably, in step S3, the carbon dioxide gas is used at a concentration of 200 h⁻¹ -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

[0041] Example 3

[0042] This embodiment relates to a method for removing trace amounts of moisture from carbon dioxide, and the specific method includes the following steps:

[0043] Preparation of S1 and K-ZSM-5: First, mix 200g of tetrapropylammonium hydroxide and 50g of deionized water evenly to obtain solution A; dissolve 0.98g of potassium aluminate in solution A to obtain solution B; add 104g of tetraethyl orthosilicate dropwise to solution B at a rate of 1mL / min, stirring in an ice-water bath during the process. After the dropwise addition is complete, continue stirring for 2 hours to obtain mixed solution C; transfer mixed solution C to a 300mL hydrothermal reactor and incubate at 150℃ for 24 hours; after the reaction is complete, remove the reactants, wash with water, centrifuge, and dry at 100℃; calcine at 550℃ for 6 hours at a rate of 1℃ / min to obtain K-ZSM-5;

[0044] S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide with a concentration of 24%. Immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide. Remove the ethanol from the immersed K-ZSM-5 under vacuum at 70°C to obtain the adsorbent.

[0045] S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove water from the carbon dioxide by chemical adsorption.

[0046] In step S1 above, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:50.

[0047] In the above text, the carbon dioxide introduced into the adsorption column is the carbon dioxide after it has been adsorbed by 5A molecular sieve, and the moisture content is 1 ppm.

[0048] Preferably, in step S3, the carbon dioxide gas is used at a concentration of 200 h⁻¹ -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

[0049] Example 4

[0050] This embodiment relates to a method for removing trace amounts of moisture from carbon dioxide, and the specific method includes the following steps:

[0051] Preparation of S1 and K-ZSM-5: First, mix 200g of tetrapropylammonium hydroxide and 50g of deionized water evenly to obtain solution A; dissolve 0.98g of potassium aluminate in solution A to obtain solution B; add 104g of tetraethyl orthosilicate dropwise to solution B at a rate of 1mL / min, stirring in an ice-water bath during the process. After the dropwise addition is complete, continue stirring for 2 hours to obtain mixed solution C; transfer mixed solution C to a 300mL hydrothermal reactor and incubate at 190℃ for 24 hours; after the reaction is complete, remove the reactants, wash with water, centrifuge, and dry at 100℃; calcine at 550℃ for 6 hours at a rate of 1℃ / min to obtain K-ZSM-5;

[0052] S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide with a concentration of 24%. Immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide. Remove the ethanol from the immersed K-ZSM-5 under vacuum at 70°C to obtain the adsorbent.

[0053] S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove water from the carbon dioxide by chemical adsorption.

[0054] In step S1 above, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:50.

[0055] In the above text, the carbon dioxide introduced into the adsorption column is the carbon dioxide after it has been adsorbed by 5A molecular sieve, and the moisture content is 1 ppm.

[0056] Preferably, in step S3, the carbon dioxide gas is used at a concentration of 200 h⁻¹ -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

[0057] Example 5

[0058] This embodiment relates to a method for removing trace amounts of moisture from carbon dioxide, and the specific method includes the following steps:

[0059] Preparation of S1 and K-ZSM-5: First, mix 200g of tetrapropylammonium hydroxide and 50g of deionized water evenly to obtain solution A; dissolve 1.96g of potassium aluminate in solution A to obtain solution B; add 104g of tetraethyl orthosilicate dropwise to solution B at a rate of 1mL / min, stirring in an ice-water bath during the process. After the dropwise addition is complete, continue stirring for 2 hours to obtain mixed solution C; transfer mixed solution C to a 300mL hydrothermal reactor and incubate at 170℃ for 24 hours; after the reaction is complete, remove the reactants, wash with water, centrifuge, and dry at 100℃; calcine at 550℃ for 6 hours at a rate of 1℃ / min to obtain K-ZSM-5;

[0060] S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide with a concentration of 24%. Immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide. Remove the ethanol from the immersed K-ZSM-5 under vacuum at 70°C to obtain the adsorbent.

[0061] S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove water from the carbon dioxide by chemical adsorption.

[0062] In step S1 above, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:25.

[0063] In the above text, the carbon dioxide introduced into the adsorption column is the carbon dioxide after it has been adsorbed by 5A molecular sieve, and the moisture content is 1 ppm.

[0064] Preferably, in step S3, the carbon dioxide gas is used at a concentration of 200 h⁻¹ -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

[0065] Example 6

[0066] This embodiment relates to a method for removing trace amounts of moisture from carbon dioxide, and the specific method includes the following steps:

[0067] Preparation of S1 and K-ZSM-5: First, mix 200g of tetrapropylammonium hydroxide and 50g of deionized water evenly to obtain solution A; dissolve 0.98g of potassium aluminate in solution A to obtain solution B; add 104g of tetraethyl orthosilicate dropwise to solution B at a rate of 1mL / min, stirring in an ice-water bath during the process. After the dropwise addition is complete, continue stirring for 2 hours to obtain mixed solution C; transfer mixed solution C to a 300mL hydrothermal reactor and incubate at 150℃ for 24 hours; after the reaction is complete, remove the reactants, wash with water, centrifuge, and dry at 100℃; calcine at 550℃ for 6 hours at a rate of 1℃ / min to obtain K-ZSM-5;

[0068] S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide with a concentration of 6%. Immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide. Remove the ethanol from the immersed K-ZSM-5 under vacuum at 70°C to obtain the adsorbent.

[0069] S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove water from the carbon dioxide by chemical adsorption.

[0070] In step S1 above, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:50.

[0071] In the above text, the carbon dioxide introduced into the adsorption column is the carbon dioxide after it has been adsorbed by 5A molecular sieve, and the moisture content is 1 ppm.

[0072] Preferably, in step S3, the carbon dioxide gas is used at a concentration of 200 h⁻¹ -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

[0073] Example 7

[0074] This embodiment relates to a method for removing trace amounts of moisture from carbon dioxide, and the specific method includes the following steps:

[0075] Preparation of S1 and K-ZSM-5: First, mix 200g of tetrapropylammonium hydroxide and 50g of deionized water evenly to obtain solution A; dissolve 0.98g of potassium aluminate in solution A to obtain solution B; add 104g of tetraethyl orthosilicate dropwise to solution B at a rate of 1mL / min, stirring in an ice-water bath during the process. After the dropwise addition is complete, continue stirring for 2 hours to obtain mixed solution C; transfer mixed solution C to a 300mL hydrothermal reactor and incubate at 150℃ for 24 hours; after the reaction is complete, remove the reactants, wash with water, centrifuge, and dry at 100℃; calcine at 550℃ for 6 hours at a rate of 1℃ / min to obtain K-ZSM-5;

[0076] S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide with a concentration of 12%. Immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide. Remove the ethanol from the immersed K-ZSM-5 under vacuum at 70°C to obtain the adsorbent.

[0077] S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove water from the carbon dioxide by chemical adsorption.

[0078] In step S1 above, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:50.

[0079] In the above text, the carbon dioxide introduced into the adsorption column is the carbon dioxide after it has been adsorbed by 5A molecular sieve, and the moisture content is 1 ppm.

[0080] Preferably, in step S3, the carbon dioxide gas is used at a concentration of 200 h⁻¹ -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

[0081] Example 8

[0082] This embodiment relates to a method for removing trace amounts of moisture from carbon dioxide, and the specific method includes the following steps:

[0083] Preparation of S1 and K-ZSM-5: First, mix 200g of tetrapropylammonium hydroxide and 50g of deionized water evenly to obtain solution A; dissolve 0.98g of potassium aluminate in solution A to obtain solution B; add 104g of tetraethyl orthosilicate dropwise to solution B at a rate of 1mL / min, stirring in an ice-water bath during the process. After the dropwise addition is complete, continue stirring for 2 hours to obtain mixed solution C; transfer mixed solution C to a 300mL hydrothermal reactor and incubate at 150℃ for 24 hours; after the reaction is complete, remove the reactants, wash with water, centrifuge, and dry at 100℃; calcine at 550℃ for 6 hours at a rate of 1℃ / min to obtain K-ZSM-5;

[0084] S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide with a concentration of 18%. Immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide. Remove the ethanol from the immersed K-ZSM-5 under vacuum at 70°C to obtain the adsorbent.

[0085] S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove water from the carbon dioxide by chemical adsorption.

[0086] In step S1 above, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:50.

[0087] In the above text, the carbon dioxide introduced into the adsorption column is the carbon dioxide after it has been adsorbed by 5A molecular sieve, and the moisture content is 1 ppm.

[0088] Preferably, in step S3, the carbon dioxide gas is used at a concentration of 200 h⁻¹ -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

[0089] The raw material content and reaction conditions used in Examples 1 to 8 are shown in Table 1 below.

[0090] Table 1

[0091]

[0092]

[0093] The carbon dioxide adsorbed in Examples 1 to 8 were tested respectively, and the results are shown in Table 2 below.

[0094] Table 2

[0095]

[0096] It is clear from the table above that, under the same conditions, the adsorbent prepared with a silicon-to-aluminum ratio of 50:1 has the best adsorption capacity.

[0097] Under the same conditions, the adsorbent prepared at a hydrothermal reaction temperature of 170℃ has the best adsorption capacity.

[0098] Under the same conditions, the adsorbent prepared with a silicon-to-aluminum ratio of 50:1 has the best adsorption capacity.

[0099] Under the same conditions, the adsorbent prepared with a potassium ethoxide concentration of 24% exhibited the best adsorption capacity.

[0100] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for removing trace amounts of moisture from carbon dioxide, characterized in that, Includes the following steps: Preparation of S1 and K-ZSM-5: First, mix tetrapropylammonium hydroxide and deionized water evenly to obtain solution A; dissolve potassium aluminate in solution A to obtain solution B; add tetraethyl orthosilicate dropwise to solution B, stir and mix; transfer solution C to a hydrothermal reactor and react for at least 2 hours. After the reaction is complete, remove the reactants, wash with water, centrifuge, and dry; continue heating to 550℃ and calcine for at least 2 hours to obtain K-ZSM-5. S2. Preparation of adsorbent: Prepare an ethanol solution of potassium ethoxide, immerse the K-ZSM-5 prepared in step S1 in the ethanol solution of potassium ethoxide, and remove the ethanol from the immersed K-ZSM-5 under vacuum to obtain the adsorbent. S3. Fill the adsorbent into the adsorption column, pass carbon dioxide into the adsorption column, and remove the water from the carbon dioxide using chemical adsorption. When the water content of the carbon dioxide after passing through the adsorption column is less than 50 ppb, the adsorption is considered complete. In step S1, the molar ratio of potassium aluminate to tetraethyl orthosilicate is 1:25~100; in step S2, the concentration of potassium ethoxide in the ethanol solution is 6%~24%.

2. The method for removing trace amounts of moisture from carbon dioxide according to claim 1, characterized in that, In step S1, the mass ratio of tetrapropylammonium hydroxide to deionized water is 1:1 to 4:

1.

3. The method for removing trace amounts of moisture from carbon dioxide according to claim 1, characterized in that, In step S1, the specific method for preparing solution C is to add tetraethyl orthosilicate dropwise to solution B at a rate of 1 mL / min, while stirring in an ice-water bath during the process. After the dropwise addition is completed, continue stirring for 2 hours to obtain solution C.

4. The method for removing trace amounts of moisture from carbon dioxide according to claim 1, characterized in that, In step S1, the temperature of the hydrothermal reaction in the hydrothermal reactor is 150℃~190℃, and the hydrothermal reaction time is 12h~36h.

5. The method for removing trace amounts of moisture from carbon dioxide according to claim 1, characterized in that, In step S1, the specific method of calcination is as follows: continue to heat at a heating rate of 1℃ / min, and calcine at 550℃ for 6 hours.

6. The method for removing trace amounts of moisture from carbon dioxide according to claim 1, characterized in that, In step S3, the carbon dioxide introduced into the adsorption column is carbon dioxide that has been adsorbed by 5A molecular sieve and contains 1 ppm of water.

7. The method for removing trace amounts of moisture from carbon dioxide according to claim 1, characterized in that, In step S3, carbon dioxide gas is used at a rate of 200 h -1 Space velocity passes through an adsorption column filled with adsorbent, and the carbon dioxide and moisture content after passing through the adsorption column are measured.

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