CN-121988278-A - Zeolite molecular sieve adsorbent and preparation method and application thereof

Abstract

The invention relates to a zeolite molecular sieve adsorbent, a preparation method and application thereof, and belongs to the technical field of molecular sieves. The preparation method of the zeolite molecular sieve adsorbent comprises the following steps of (1) preparing a solution A containing a silicon source, an acid source and rare earth metal salt, preparing a solution B containing an aluminum source and an alkali source, (2) mixing the solution A obtained in the step (1) with the solution B, performing ultrasonic aging to obtain aged slurry, and (3) performing microwave crystallization, washing and drying on the aged slurry obtained in the step (2) to obtain the zeolite molecular sieve adsorbent. The preparation method adopts rare earth elements for doping to obtain the rare earth element doped zeolite molecular sieve, and the pore diameter of the zeolite molecular sieve can be accurately regulated and controlled by the introduction of the rare earth elements, so that the difficult-to-divide accurate and efficient screening of carbon dioxide/acetylene, carbon dioxide/nitrogen, carbon dioxide/methane, methane/nitrogen and the like is realized.

Inventors

• HU GUOPING
• LIU CHENGHAO

Assignees

• 中国科学院赣江创新研究院

Dates

Publication Date

20260508

Application Date

20260121

Claims (10)

1. 1. A method for preparing a zeolite molecular sieve adsorbent, comprising the steps of: (1) Preparing a solution A containing a silicon source, an acid source and rare earth metal salt, and preparing a solution B containing an aluminum source and an alkali source; (2) Mixing the solution A and the solution B obtained in the step (1), and performing ultrasonic aging to obtain aged slurry; (3) And (3) carrying out microwave crystallization, washing and drying on the aged slurry obtained in the step (2) to obtain the zeolite molecular sieve adsorbent.
2. 2. The method for preparing a zeolite molecular sieve adsorbent according to claim 1, wherein in the step (1), the molar ratio of the silicon element in the silicon source to the rare earth element in the rare earth metal salt in the solution a is 1 (0.0001-0.2).
3. 3. The method of claim 1, wherein in step (1), the molar ratio of the silicon element in the silicon source to the acid source in the solution a is 1 (0.01-2.5).
4. 4. The method of preparing a zeolite molecular sieve adsorbent according to claim 1, wherein in step (1), the molar ratio of the aluminum element in the aluminum source to the alkali source in the solution B is 1 (1-20).
5. 5. The method of claim 1, wherein in step (1), the molar ratio of the silicon element in the silicon source to the aluminum element in the aluminum source is 1 (0.1-1).
6. 6. The method according to claim 1, wherein in the step (1), the silicon source comprises at least one of sodium silicate, tetraethyl silicate, and silica sol, and/or the acid source comprises hydrochloric acid, and/or the rare earth metal in the rare earth metal salt comprises at least one of cerium, praseodymium, neodymium, samarium, europium, and terbium, and/or the aluminum source comprises at least one of aluminum sulfate, aluminum hydroxide, aluminum chloride, and aluminum nitrate, and/or the alkali source comprises sodium hydroxide.
7. 7. The method for preparing zeolite molecular sieve adsorbent according to claim 1, wherein in the step (3), the temperature of the microwave crystallization is 110 ℃ to 220 ℃ for 1 day to 16 days.
8. 8. The method according to claim 1, wherein in the step (2), the ultrasonic aging is performed for a time of 1h to 24h, and/or in the step (3), the washing is performed with water until a washing liquid is neutral, and/or in the step (3), the drying is performed at a temperature of 50 ℃ to 150 ℃ for a time of 2h to 24h.
9. 9. A zeolite molecular sieve adsorbent produced by the process for producing a zeolite molecular sieve adsorbent according to any one of claims 1 to 8.
10. 10. Use of the zeolite molecular sieve adsorbent of claim 9 in gas separation.

Description

Zeolite molecular sieve adsorbent and preparation method and application thereof Technical Field The invention belongs to the technical field of molecular sieves, and particularly relates to a zeolite molecular sieve adsorbent, a preparation method and application thereof. Background For the separation of many critical industrial gas mixtures (e.g., CO2/C2H2、CO2/N2、CO2/CH4、CH4/N2, etc.), since the molecular size and physicochemical properties of the components are very close, the efficient separation relies on precise sub-angstrom scale control of the pore size of the separation material. Zeolite as a porous crystalline material with regular pore channels exhibits potential in this field, but its separation selectivity is highly dependent on precise control of pore channel dimensions. Currently, achieving precise, controllable pore modification at the sub-angstrom level remains a key challenge. The existing pore diameter regulating strategy is mostly dependent on indirect physical or chemical modification, and is often difficult to balance between precision, controllability and structural stability. For example, the method of pore shrinkage of zeolite by calcination is often accompanied by uncontrollable partial collapse of the framework, the strategy of realizing a "gating effect" by cation oscillation depending on temperature change, the performance of which is strictly limited by an operating temperature window, the method of pore shrinkage by reducing framework silica-alumina ratio and introducing more extra-framework cations, the method of cation position randomization caused by aluminum maldistribution is easy to predict, and the method of ion exchange or introducing non-framework species, the control accuracy of which is limited by the size of the ion or the species itself and limited available sites in the framework. These methods often have difficulty achieving continuous, precise pore size adjustment, often resulting in an excessively wide or narrow effective pore size distribution, thereby affecting separation selectivity. Therefore, a new universal method capable of accurately, flexibly and structurally stably regulating and controlling the pore diameter of zeolite is developed, and is very important to promote the application of the zeolite in various high-difficulty gas separations. Disclosure of Invention The invention aims to overcome the problems in the prior art and provide a zeolite molecular sieve adsorbent, a preparation method and application thereof. The invention is realized by the following technical scheme: in a first aspect, the present invention provides a method for preparing a zeolite molecular sieve adsorbent comprising the steps of: (1) Preparing a solution A containing a silicon source, an acid source and rare earth metal salt, and preparing a solution B containing an aluminum source and an alkali source; (2) Mixing the solution A and the solution B obtained in the step (1), and performing ultrasonic aging to obtain aged slurry; (3) And (3) carrying out microwave crystallization, washing and drying on the aged slurry obtained in the step (2) to obtain the zeolite molecular sieve adsorbent. The preparation method adopts rare earth elements for doping to obtain the rare earth element doped zeolite molecular sieve, and the pore diameter of the zeolite molecular sieve can be accurately regulated and controlled by the introduction of the rare earth elements, so that the difficult-to-divide accurate and efficient screening of carbon dioxide/acetylene, carbon dioxide/nitrogen, carbon dioxide/methane, methane/nitrogen and the like is realized. The microwave crystallization is a process of dissolving and recrystallizing insoluble substances to form dispersed nanocrystal cores in a closed high-pressure reactor by taking aqueous solution as a medium and adopting a high-temperature high-pressure environment and microwaves. Preferably, in the step (1), the silicon source includes at least one of sodium silicate, tetraethyl silicate, and silica sol. The zeolite molecular sieve obtained by adopting different silicon sources has good cleanliness, wide synthesis conditions and high molecular sieve stability. Preferably, in the step (1), the acid source includes hydrochloric acid. Preferably, in the step (1), the rare earth metal in the rare earth metal salt includes at least one of cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), terbium (Tb). The research of the invention discovers that the rare earth elements can realize good methane and nitrogen separation effect when being doped. Specifically, in the step (1), the rare earth metal salt includes a rare earth metal nitrate. Preferably, in the step (1), the molar ratio of the silicon element in the silicon source to the rare earth element in the rare earth metal salt is 1 (0.0001-0.2), and more preferably, in the step (1), the molar ratio of the silicon element in the silicon source to the rare earth element in