LU502475B1

LU502475B1 - Cu(I) LOADED MOLECULAR SIEVE ADSORBENT, PREPARATION METHOD THEREFOR, AND APPLICATIONS THEREOF

Info

Publication number: LU502475B1
Application number: LU502475A
Authority: LU
Inventors: Yonghou Xiao; Xu Liu; Shuohan Yang; Zhengqi Liang; Yushan Li
Original assignee: Dalian Univ Of Technology Panjin Institute Of Industrial Technology
Priority date: 2022-03-30
Filing date: 2022-07-07
Publication date: 2023-01-11
Also published as: CN114558546A; CN114558546B

Abstract

The present invention provides a Cu(I) loaded molecular sieve adsorbent, a preparation method therefor, and applications thereof. The preparation method includes the following steps: selecting a molecular sieve and drying the molecular sieve; adding the molecular sieve into an alcohol solvent and stirring at room temperature until the two are evenly mixed; slowly adding a monovalent copper salt powder and stirring at room temperature to obtain a mixture; and filtering, drying, molding, and grinding the mixture, to obtain a Cu(I) loaded molecular sieve adsorbent. The whole preparation process is safe and simple without synthesizing in a harsh environment such as a dry inert atmosphere or vacuum, and is environmentally friendly and saves energy consumption. The Cu(I) loaded molecular sieve adsorbent provided in the present invention is modified by introducing copper ions through a one-step method, which can increase an adsorption capacity for carbon monoxide of the molecular sieve. The adsorption capacity for CO reaches 4.1 mmol/g at a temperature of 25oC and a pressure of 1000 mbar.

Description

Cu(D) LOADED MOLECULAR SIEVE ADSORBENT, PREPARATION METHOD THEREFOR, AND APPLICATIONS

THEREOF TECHNICAL FIELD

[0001] The present invention relates to the field of adsorption technologies and adsorption materials, and in particular, to a Cu(I) loaded molecular sieve adsorbent, a preparation method therefor, and applications thereof.

BACKGROUND

[0002] As an important clean and renewable energy, hydrogen is still difficult to be utilized efficiently. Methanol to hydrogen is considered to be one of the most promising applications of the hydrogen production technologies for use in hydrogen fuel cells, but hydrogen produced by this method often contains gas impurities such as carbon monoxide (CO). A trace of CO may poison a catalyst in fuel cell, so that normal operation of the cell is affected. Especially for a hydrogen fuel cell with a platinum-based catalyst, the content of CO needs to be as low as 0.2 ppmv. Therefore, hydrogen produced from methanol reforming needs to be purified. The adsorption separation method is a method to achieve efficient separation through adsorption, enrichment, and desorption of an adsorption bed by using differences in adsorption capacities and selectivity of an adsorbent to different gas components. Different desorption regeneration methods can be classified into temperature swing adsorption (TSA) and pressure swing adsorption (PSA). The TSA realizes regeneration and separation based on differences in adsorption capacities of an adsorbent at different temperatures, and the PSA realizes regeneration and separation based on differences in adsorption capacities of the adsorbent at different pressures. Obviously, a heating and cooling process through variable temperatures is extremely energy consuming. In contrast, the PSA process has a faster regeneration rate, low energy consumption, simple equipment, and high degree of automation, and is easy for large-scale industrial production. At present, many types of adsorbents, such as porous carbon, porous organic polymers, and metal organic skeletons, are being widely studied with obvious 1 performance effects. Therefore, the adsorption separation technology is expected to replace the | LU502475 cryogenic separation technology in the near future.

[0003] Patent CN1103816A discloses a method for preparing a zeolite adsorbent for adsorbing carbon monoxide with high selectivity, in which an ion exchange and impregnation method is used to load cupric ions on NaY zeolite. However, zeolite, kaolin clay, and a pore expanding agent need to be mixed and extruded first, then a composite carrier is prepared by treating with a NaOH aqueous solution containing SiO», then Cu(II )-Y zeolite is exchanged with Cu?" ions, and finally a finished product is prepared by reducing with CO or Hy. The process is complicated with high costs. Patent CN112705180A discloses a method for preparing an adsorbent for CO pressure swing adsorption, in which gas-solid phase treatment is carried out on a modified carrier by using organic amine, and then the modified carrier is mixed with a copper source and is molded, to obtain an adsorbent precursor. In this case, problems that a conventional adsorbent is low in mechanical strength and low in CO adsorption efficiency are resolved. However, the carrier still needs to be modified by using an aluminum source and a phosphoric acid first, and dispersion of copper ions is low.

[0004] In view of the above, although some methods for preparing an adsorbent for adsorbing carbon monoxide have been reported in previous literature, the methods all have problems of a complicated preparation process and high costs. A technical problem that needs to be resolved at present is how to find a simple and fast adsorbent preparation method and meanwhile achieve: a. high pore volume, high specific surface area, and high adsorption capacity of the adsorbent; b. high selectivity to carbon monoxide, an obvious separation effect in a separation system of hydrogen and carbon monoxide; and c. high dispersion of copper ions.

SUMMARY

[0005] To resolve the problems existing in the background technology, the present invention proposes a novel carbon monoxide adsorbent that is rapidly synthesized in one step. For problems of low adsorption capacity, low adsorption rate, low adsorption selectivity, and complicated preparation of an existing CO adsorbent, the preparation method has simple steps and is easy to be implemented. The novel carbon monoxide adsorbent has advantages of large adsorption capacity and high selectivity. 2

[0006] First, the present invention provides a method for preparing a Cu(I) loaded molecular | LU502475 sieve adsorbent, including the following steps:

[0007] selecting a molecular sieve, and drying the molecular sieve;

[0008] adding the molecular sieve into an alcohol solvent and stirring at room temperature until the two are evenly mixed;

[0009] slowly adding a monovalent copper salt powder and stirring at room temperature to obtain a mixture; and

[0010] filtering, drying, compressing to mold, and grinding the mixture, to obtain a Cu(l) loaded molecular sieve adsorbent.

[0011] Preferably, the molecular sieve is one or more of a 5A molecular sieve, a ZSM-5 molecular sieve, a 13X molecular sieve, or a NaY molecular sieve.

[0012] Preferably, the monovalent copper salt is one or more of cuprous chloride or cuprous sulfate.

[0013] Preferably, the alcohol solvent is one or more of ethanol, methanol, propanol, or butanol.

[0014] Preferably, a mole ratio of the molecular sieve, the monovalent copper salt, and the alcohol solvent is (0.8-1.2):(0.1-0.4):(20-50).

[0015] Preferably, a temperature for drying the molecular sieve is 80-120°C, and drying time is 8-16 h.

[0016] Preferably, the temperature for drying is 80-120°C, and the drying time is 8-16 h.

[0017] Preferably, a pressure for compression molding is 1.0-2.5 MPa, and a grinding mesh quantity of the grinding is 20-80 meshes.

[0018] Further, the present invention also provides a Cu(I) loaded molecular sieve adsorbent prepared by the preparation method of Cu(I) loaded molecular sieve adsorbent.

[0019] The present invention also provides a Cu(l) loaded molecular sieve adsorbent for adsorbing carbon monoxide.

[0020] Beneficial effects:

[0021] 1) In the present invention, different molecular sieves are used as the carriers, cuprous chloride is used as a copper source, and the two are mixed in an ethanol solution by using a one-step method, so as to directly prepare the Cu(I) loaded molecular sieve adsorbent. The use 3 of an alcohol solvent can significantly improve the dispersion of cuprous ions. Liquid-phase | LU502475 reduction conditions are provided in the preparation process to effectively protect monovalent Cu(I), which avoids the monovalent Cu(l) from being oxidized to Cu** due to contact with air, so as to ensure that a surface and pores of the molecular sieves are more evenly loaded with monovalent copper ions. Existing adsorbent preparation methods are mostly ion exchange methods, through which copper ions cannot be uniformly loaded in pores of the molecular sieve and a Cu load also cannot be controlled. Compared with the ion exchange method, the solutions of the present invention have advantages of low costs, simple process, and environmental friendliness.

[0022] 2) Compared with the common impregnation method and double solvent method for carbon monoxide adsorption, in the present invention, the monovalent cuprous ions loaded more uniformly on the surface and in the pores provide x complexation, which greatly improves the adsorption capacity, and thus the present invention has advantages of high activity, high stability, and high reproducibility. Meanwhile, compared with the existing technology in which the monovalent cuprous salt is loaded on the molecular sieves, generally grinding is required first and then heating at a high temperature in an inert gas is carried out. Inert gas protection is not required during the preparation process in this application, and no harsh conditions such as high temperature and high pressure are required. Therefore, this method is safe, simple, environmentally friendly, and energy saving. In addition, the method in this application can enable the surface and the pores of the molecular sieve to load the monovalent cuprous ions more uniformly. Through monovalent copper modification of the molecular sieve, CO forms a x complexation bond with monovalent copper, where the x complexation bond is stronger than van the der Waals force. Therefore, the prepared molecular sieve adsorbent on one hand can improve the selectivity to CO, and resolve a problem that a separation effect in a separation system of hydrogen and carbon monoxide is not obvious; and on the other hand, can improve the adsorption capacity for CO. Therefore, the molecular sieve adsorbent prepared by using this method can maintain excellent adsorption performance and selectivity at room temperature and good regeneration performance, and is suitable for a carbon monoxide adsorption and separation process.

[0023] 3) In the present invention, the adsorbent selects 5A, ZSM-5, 13X, and NaY molecular 4 sieves with more appropriate pore sizes as a matrix, where the pore sizes are 1.33-2.5 times of | LU502475 the kinetic diameter of carbon monoxide; and has a good adsorption effect and is easy for operation.

BRIEF DESCRIPTION OF DRAWINGS

[0024] Contents expressed in the accompanying drawings in the specification are briefly described below:

[0025] FIG 1 is a flowchart of a method for preparing a Cu(l) loaded molecular sieve adsorbent according to this application;

[0026] FIG 2 is a carbon monoxide adsorption isotherm test chart of a Cu(I) loaded molecular sieve adsorbent prepared in Embodiments 1 to 5 in this application;

[0027] FIG 3 is a carbon monoxide adsorption isotherm test chart of a Cu(I) loaded molecular sieve adsorbent prepared in Embodiment 3 and Comparative Examples 1 to 5 in this application;

[0028] FIG 4 is a carbon monoxide adsorption isotherm test chart of a Cu(I) loaded molecular sieve adsorbent prepared in Embodiment 1 and Comparative Examples 6 to 10 in this application; and

[0029] FIG 5 is a carbon monoxide adsorption isotherm test chart of a Cu(I) loaded molecular sieve adsorbent according to Comparative Examples 11 to 14 in this application.

DESCRIPTION OF EMBODIMENTS

[0030] The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are merely some embodiments of the present invention and are not all embodiments. According to the embodiments of the present invention, all other embodiments derived by persons of ordinary skills in the art without an effective effort fall within the protection scope of the present invention.

[0031] The embodiment section of this application provides a Cu(I) loaded molecular sieve adsorbent and a preparation method therefor. As shown in FIG 1, the following steps are included: 5

[0032] S1: Select a molecular sieve, and dry the molecular sieve; LU502475

[0033] S2: Add the molecular sieve into an alcohol solvent and stir at room temperature until the two are evenly mixed:

[0034] S3: Slowly add a monovalent copper salt powder and stir at room temperature to obtain a mixture; and

[0035] S4: Filter, dry, compress to mold, and grind the mixture, to obtain a Cu(l) loaded molecular sieve adsorbent.

[0036] Embodiment 1

[0037] 1 g 5A molecular sieve was dried and was mixed evenly with 30 mL ethanol. The two were stirred at temperature room temperature for 10 min, then 0.1 g cuprous sulfate was slowly added therein, and stirring was carried out at room temperature for 3 h. The produced mixture was filtered, was dried at 75°C for 12 h, and was performed with compression molding after being pretreated, where a pressure was 1.5 MPa, and a grinding mesh quantity was 60 meshes. In this way, a Cu(I) loaded 5A adsorbent was obtained.

[0038] Embodiment 2

[0039] 1 g 5A molecular sieve was dried and was mixed evenly with 30 mL ethanol. The two were stirred at temperature room temperature for 10 min, then 0.2 g cuprous chloride was slowly added therein, and stirring was carried out at room temperature for 3 h. The produced mixture was filtered, was dried at 75°C for 12 h, and was performed with compression molding after being pretreated, where a pressure was 1.5 MPa, and a grinding mesh quantity was 60 meshes. In this way, a Cu(I) loaded 5A adsorbent was obtained.

[0040] Embodiment 3

[0041] 1 g 5A molecular sieve was dried and was mixed evenly with 30 mL ethanol. The two were stirred at temperature room temperature for 10 min, then 0.3 g cuprous chloride was slowly added therein, and stirring was carried out at room temperature for 3 h. The produced mixture was filtered, was dried at 75°C for 12 h, and was performed with compression molding after being pretreated, where a pressure was 1.5 MPa, and a grinding mesh quantity was 60 meshes. In this way, a Cu(I) loaded 5A adsorbent was obtained.

[0042] Embodiment 4

[0043] 1 g 13X molecular sieve was dried and was mixed evenly with 30 mL ethanol. The 6 two were stirred at temperature room temperature for 10 min, then 0.4 g cuprous chloride was | LU502475 slowly added therein, and stirring was carried out at room temperature for 3 h. The produced mixture was filtered, was dried at 75°C for 12 h, and was performed with compression molding after being pretreated, where a pressure was 1.5 MPa, and a grinding mesh quantity was 60 meshes. In this way, a Cu(I) loaded 13X adsorbent was obtained.

[0044] Embodiment 5

[0045] 1 g NaY molecular sieve was dried and was mixed evenly with 30 mL ethanol. The two were stirred at temperature room temperature for 10 min, then 0.5 g cuprous chloride was slowly added therein, and stirring was carried out at room temperature for 3 h. The produced mixture was filtered, was dried at 75°C for 12 h, and was performed with compression molding after being pretreated, where a pressure was 1.5 MPa, and a grinding mesh quantity was 60 meshes. In this way, a Cu(I) loaded NaY adsorbent was obtained.

[0046] Carbon monoxide adsorption tests were carried out on an IGA intelligent gravimetric analyzer by using the adsorbents prepared as described in Embodiments 1 to 5. Purity of carbon monoxide in a gas is 99.9%, and experimental conditions of an activity test of the adsorbent are as follows: a temperature is 25°C, and a pressure range is 0—1000 mbar. After filling the Cu(I) loaded molecular sieve adsorbent, a static adsorption test is carried out on the IGA intelligent gravimetric analyzer, to detect a mass change in a sample tube and obtain a static adsorption capacity. Results are shown in FIG 2. It can be seen that the adsorbents prepared according to the solutions in this application all have ideal adsorption effects for CO, where a maximum adsorption capacity is up to 4.12 mmol/g (25°C, and 1000 mbar).

[0047] Comparative Example 1

[0048] 1 g 5A molecular sieve was dried and was mixed evenly with 30 mL water. The two were stirred at temperature room temperature for 10 min, then 0.1 g cuprous chloride was slowly added therein, and stirring was carried out at room temperature for 3 h. The produced mixture was filtered, was dried at 75°C for 12 h, and was performed with compression molding after being pretreated, where a pressure was 1.5 MPa, and a grinding mesh quantity was 60 meshes. In this way, a Cu(I) loaded 5A adsorbent was obtained.

[0049] Comparative Examples 2 to 5

[0050] The Cu(l)/5A adsorbent was prepared according to the steps and the conditions 7 described in Comparative Example 1 and adsorption tests were carried out. Only the addition =~ LU502475 amount of cuprous chloride was changed, and the conditions for changing were listed in Table

1.

[0051] Carbon monoxide adsorption tests were carried out on an IGA intelligent gravimetric 5S analyzer by using the adsorbent prepared as described in Comparative Examples 1 to 5. Purity of carbon monoxide in a gas is 99.9%, and experimental conditions of an activity test of the adsorbent are as follows: a temperature is 25°C, and a pressure range is 0—1000 mbar. After filling the Cu(I)loaded molecular sieve adsorbent, a static adsorption test is carried out on the IGA intelligent gravimetric analyzer, to detect a mass change in a sample tube and obtain a static adsorption capacity. Results are shown in FIG 3. By comparing with the test results of Embodiment 3, it can be seen that when water is used instead of alcohol solvent in the preparation process, an adsorption effect for CO of the prepared adsorbent is not as good as the solution provided in this application.

[0052] Comparative Example 6

[0053] 1 g 5A molecular sieve was dried, and was mixed and ground with 0.1 g cuprous chloride at room temperature. The produced mixture was filtered and was heated at 400°C in inert gas atmosphere for 12 h to obtain a Cu(1)/5A adsorbent.

[0054] Comparative Examples 7 to 10

[0055] The Cu(I)/5A adsorbent was prepared according to the steps and the conditions described in Embodiment 1 and adsorption tests were carried out. Only the addition amount of cuprous chloride was changed, and the conditions for changing were listed in Table 1.

[0056] Carbon monoxide adsorption tests were carried out on an IGA intelligent gravimetric analyzer by using the adsorbent prepared as described in Comparative Examples 6 to 10. Purity of carbon monoxide in a gas is 99.9%, and experimental conditions of an activity test of the adsorbent are as follows: a temperature is 25°C, and a pressure range is 0-1000 mbar. After filling the Cu(I) loaded molecular sieve adsorbent, a static adsorption test is carried out on the IGA intelligent gravimetric analyzer, to detect a mass change in a sample tube and obtain a static adsorption capacity. Results are shown in FIG 4. By comparing with the test results of Embodiment 1, it can be seen that when the molecular sieve is directly ground and mixed with a copper source without a solvent in the preparation process, an adsorption effect for CO of the 8 prepared adsorbent is not as good as the solution provided in this application. LU502475

[0057] Comparative Example 11

[0058] The adsorbent was prepared according to an impregnation method. 1 g SA molecular sieve was mixed evenly with 30 mL water, the two were stirred at room temperature for 10 min, then 0.3 g cuprous chloride was slowly added therein, and stirring was carried out at room temperature for 3 h. The produced mixture was reduced under a vacuum condition at 200°C for 12 h, and was performed with compression molding after being pretreated. In this way, a Cu(I) loaded 5A adsorbent was obtained.

[0059] Comparative Example 12

[0060] The adsorbent was prepared according to an impregnation method. 1 g 5A molecular sieve was mixed evenly with 30 parts of ethanol, the two were stirred at room temperature for 10 min, then 0.3 g copper sulfate was slowly added therein, and stirring was carried out at room temperature for 3 h. The produced mixture reduced under a vacuum condition at 200°C for 12 h, and was performed with compression molding after being pretreated. In this way, a Cu(I)/5A adsorbent was obtained.

[0061] Comparative Example 13

[0062] The adsorbent was synthesized according to a dual-solvent method. 1 g SA molecular sieve was mixed evenly with 200 mL n-hexane. The solution was first sonicated at room temperature for 30 min, and then stirred at room temperature for 10 min. 18 mL aqueous solution containing 0.3 g copper chloride was slowly added to the stirred solution, and was stirred at room temperature for 4 h. The produced mixture was reduced under a vacuum condition at 200°C for 12 h, and was performed with compression molding after being pretreated. In this way, a Cu(I)/SA adsorbent was obtained.

[0063] Comparative Example 14

[0064] The adsorbent was synthesized according to a double-solvent method. 1 g 5A molecular sieve was mixed evenly with 200 mL n-hexane. The solution was first sonicated at room temperature for 30 min, and then stirred at room temperature for 10 min. 18 mL aqueous solution containing 0.3 g copper chloride was slowly added to the stirred solution, and was stirred at room temperature for 4 h. The produced mixture was reduced under a vacuum condition at 200°C for 12 h, and was performed with compression molding after being 9 pretreated. In this way, a Cu(I)/SA adsorbent was obtained. LU502475

[0065] Carbon monoxide adsorption tests were carried out on an IGA intelligent gravimetric analyzer by using the adsorbent prepared as described in Comparative Examples 11 to 14. Purity of carbon monoxide in a gas is 99.9%, and experimental conditions of an activity test of the adsorbent are as follows: a temperature is 25°C, and a pressure range is 0—1000 mbar. After filling the Cu(I) loaded molecular sieve adsorbent, a static adsorption test is carried out on the IGA intelligent gravimetric analyzer, to detect a mass change in a sample tube and obtain a static adsorption capacity. Results are shown in FIG 5. It can be seen that an adsorption effect for CO of the adsorbent prepared according to the conventional impregnation method or dual-solvent method is still not as good as the solution provided in this application.

[0066] Results of carbon monoxide adsorption tests in various embodiments and comparative examples at a temperature of 25°C and a pressure of 1000 mbar are shown in Table 1. Table 1 Component addition amount and adsorption test result in each embodiment and comparative example Molecular Copper Molecular sieve: CO adsorption Number sieve source Copper source (Wt: wt) capacity (mmol/g) Embodiment | Embodiment 2 Embodimen 3 Embodiment 4 Embodimen 5 Comparative 5A CuCl 1:0.1 1.48 example 1 Comparative 5A CuCl 1:0.2 1.64 example 2 Comparative 5A CuCl 1:0.3 1.85 example 3 Comparative 5A CuCl 1:04 1.77 example 4 10

Comparative 5A CuCl 1:0.1 2.35 example 6 Comparative 5A CuCl 1:0.2 2.49 example 7 Comparative 5A CuCl 1:0.3 2.64 example 8 Comparative 5A CuCl 1:04 2.63 example 9 Comparative 5A CuCl 1:0.5 2.52 example 10 Comparative 5A CuCl, 1:0.3 1.29 example 11 Comparative 5A CuSO4 1:0.3 1.37 Example 12 Comparative 5A CuCl, 1:0.3 1.53 example 13 Comparative 5A CuSO4 1:0.3 1.69 example 14

[0067] It can be seen from the comparison results of the examples and the comparative examples that the technical solutions provided in the present invention can well resolve the problems of low adsorption capacity, low adsorption rate, and poor adsorption selectivity, and achieve good technical effects.

[0068] It is obvious to a person skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered in all respects to be exemplary and non-restrictive, and the scope of the present invention is subject to the appended claims other than the descriptions described above, so that all variations falling within the 11 meaning and the scope of the equivalent elements of the claims are intended to be included LU502475 therein. 12

Claims

CLAIMS What is claimed 1s:

1. A method for preparing a Cu(l) loaded molecular sieve adsorbent, which is characterized by comprising the following steps: selecting a molecular sieve, and drying the molecular sieve; adding the molecular sieve into an alcohol solvent and stirring at room temperature until the two are evenly mixed; slowly adding a monovalent copper salt powder and stirring at room temperature to obtain a mixture; and filtering, drying, molding, and grinding the mixture, to obtain a Cu(I) loaded molecular sieve adsorbent.

2. The method for preparing a Cu (I) loaded molecular sieve adsorbent according to claim 1, which is characterized in that the molecular sieve is one or more of a 5A molecular sieve, a ZSM-5 molecular sieve, a 13X molecular sieve, or a NaY molecular sieve.

3. The method for preparing a Cu(I) loaded molecular sieve adsorbent according to claim 1, which is characterized in that the monovalent copper salt is one or more of cuprous chloride or cuprous sulfate.

4. The method for preparing a Cu(I) loaded molecular sieve adsorbent according to claim 1, which is characterized in that the alcohol solvent is one or more of ethanol, methanol, propanol, or butanol.

5. The method for preparing a Cu(I) loaded molecular sieve adsorbent according to claim 1, which is characterized in that a mass ratio of the molecular sieve, the monovalent copper salt, and the alcohol solvent is (0.8-1.2):(0.1-0.4):(20-50).

6. The method for preparing a Cu (I) loaded molecular sieve adsorbent according to claim 1, which is characterized in that a temperature for drying is 60-120°C, and drying time is 8-16 h.

7. The method for preparing a Cu (I) loaded molecular sieve adsorbent according to claim 1, which is characterized in that a pressure for compression molding is 1.0-2.5 MPa, and a grinding mesh quantity of the grinding is 20-80 meshes.

8. A Cu(l) loaded molecular sieve adsorbent, being prepared by using the method according 13 to any one of claims 1 to 7. LU502475

9. The Cu(l) loaded molecular sieve adsorbent according to claim 8 is applied for adsorbing carbon monoxide. 14