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CN-117753385-B - Covalent organic framework material for xenon and nitrogen separation and preparation method and application thereof

CN117753385BCN 117753385 BCN117753385 BCN 117753385BCN-117753385-B

Abstract

The invention discloses a covalent organic framework material for xenon nitrogen separation, a preparation method and application thereof, wherein a phenanthroline with high affinity to metal ions is selected, two-dimensional and three-dimensional covalent organic frameworks are respectively prepared by taking the phenanthroline as a monomer, a large number of adsorption sites can be provided for the metal ions by the phenanthroline covalent organic framework structural units which are periodically arranged, meanwhile, the metal ions are introduced on the surface of a covalent organic framework hole by utilizing the stronger adsorption effect of the metal ions on Xe to serve as the contactable polar sites, the capacity of the covalent organic framework hole for inducing Xe polarization is enhanced, the adsorption separation efficiency is improved, the material prepared by the invention has good xenon nitrogen separation performance, the xenon adsorption capacity of the covalent organic framework after nickel ions are adsorbed is improved by 2.24 times, and the xenon adsorption capacity can reach 8.7 cm 3 /g under the conditions of 298K and 1 bar, and the selectivity of IAST can reach 3.8. The organic covalent framework gas separation performance is good, and the organic covalent framework gas separation method has important significance for high-performance xenon nitrogen separation.

Inventors

  • LIU XUE
  • MI LIJIE
  • WANG JIALIN
  • Ding Yehui
  • WANG RUXUAN

Assignees

  • 西安交通大学

Dates

Publication Date
20260508
Application Date
20240103

Claims (8)

  1. 1. A method for preparing a covalent organic framework material for xenon nitrogen separation, characterized by comprising the following steps: firstly, preparing an hydroformylation monomer of phenanthroline; then, synthesizing a covalent organic framework by utilizing an hydroformylation monomer of the phenanthroline; the covalent organic frameworks are respectively a two-dimensional sp 2 carbon-carbon connected phenanthroline covalent organic framework and a three-dimensional imine connected phenanthroline covalent organic framework; And finally, according to the property of the phenanthroline, modifying the surface of the hole by using metal ions, introducing the metal ions on the covalent organic framework to adjust the surface electric field of the covalent organic framework, and promoting the selective adsorption of the covalent organic framework to xenon to obtain the covalent organic framework material for separating xenon from nitrogen.
  2. 2. The method for preparing the covalent organic framework material for xenon nitrogen separation, which is characterized in that the preparation method of the hydroformylation monomer of the phenanthroline is characterized in that 3, 8-dibromo-1, 10-phenanthroline, 4-formylphenyl pinacol ester and potassium carbonate are added into a mixed solvent of tetrahydrofuran and deionized water according to the molar ratio of (0.5-1) (1-3) (1-4), tetra (triphenylphosphine) palladium with the molar amount of 0.05-0.3 times of that of 3, 8-dibromo-1, 10-phenanthroline is added after nitrogen is introduced for a period of time, and the hydroformylation phenanthroline monomer is obtained by reacting 24-72 h in a nitrogen atmosphere at 60-80 ℃.
  3. 3. The method for preparing a covalent organic framework material for xenon nitrogen separation according to claim 1, wherein the preparation method of the two-dimensional sp 2 carbon-linked phenanthroline covalent organic framework is characterized in that an aldehyde phenanthroline monomer, 2,4, 6-trimethyl-1, 3, 5-triazine, benzoic acid and benzoic anhydride are added into a Pyrex tube according to the molar ratio of (1-3): (1-2): (0.1-1): (1-6), the glass tube is sealed by using flame after quick freezing of liquid nitrogen, and the two-dimensional covalent organic framework for xenon nitrogen separation is obtained by reacting 48-72 h at 120-180 ℃.
  4. 4. The method for preparing the covalent organic framework material for xenon nitrogen separation according to claim 1, wherein the preparation method of the three-dimensional imine-linked phenanthroline covalent organic framework is characterized in that aldehyde-linked phenanthroline monomers and tetra (4-aminophenyl) methane are added into a Pyrex tube according to the proportion of (1-4): (0.5-2), then a mixed solution of trimesic acid and 1, 4-dioxane is added, 3-9mol/L acetic acid solution and trimesic acid are added after ultrasonic homogenization, the volume ratio of 1, 4-dioxane and acetic acid solution is (5-9): (1-5): (0.4-1.2), the glass tube is sealed by using flame after liquid nitrogen quick freezing, and the three-dimensional covalent organic framework for xenon nitrogen separation is obtained by reacting 48-72 h at the temperature of 120-180 ℃.
  5. 5. The method for preparing the covalent organic framework material for xenon nitrogen separation according to claim 1, wherein the specific method for modifying the surface of the covalent organic framework hole by using metal ions is to prepare 1-10g/L of metal salt solution, 1-10mg of organic covalent framework is soaked in 10mL of metal salt solution, stirring is carried out for 8-24h, ultrasound is carried out for 10min at the beginning and the end respectively, and solid products are collected by filtration after the end, so that the covalent organic framework material modified by the metal ions is the covalent organic framework material for xenon nitrogen separation.
  6. 6. The method of claim 5, wherein the metal salt is nickel chloride, europium chloride hexahydrate or cobalt chloride.
  7. 7. A covalent organic framework material for xenon nitrogen separation prepared by the preparation method according to any one of claims 1 to 6.
  8. 8. Use of the covalent organic framework material for xenon nitrogen separation as claimed in claim 7 for xenon separation.

Description

Covalent organic framework material for xenon and nitrogen separation and preparation method and application thereof Technical Field The invention belongs to the field of material preparation, relates to a preparation method of a covalent organic framework material, and in particular relates to a covalent organic framework material for xenon-nitrogen separation, and a preparation method and application thereof. Background Xenon (Xe) is an important rare gas in national economy, and is expensive and used in industries such as illumination display, electronic chips, satellite medical treatment, building doors and windows, and the like. As the nuclear energy of clean energy, plays an irreplaceable role in the process of realizing carbon neutralization and carbon peak in China. However, the natural abundance of rare gases decreases with increasing atomic number and directly affects their price in the market. Taking the price on the market as an example, the price per gram of xenon can be comparable to, or even higher than, the price of gold. The reduction in market price for high quality xenon will facilitate the development of the medical and commercial industries and promote the development of new xenon applications. The high cost of xenon stems from the current energy and capital intensive air cryogenic distillation separation process, as well as the low concentration of xenon in air. The traditional krypton-xenon separation is usually carried out by low-temperature distillation based on the boiling point difference of krypton-xenon molecules, the process of the method is mature, large-scale industrialization is realized, however, the method has high requirements on equipment, consumes huge energy and does not meet the requirements of low carbon and environmental protection. The use of nanoporous adsorbents to selectively adsorb xenon from exhaust gases is an important direction of development in recent years. Porous materials with tailored pore sizes, functionalizable surfaces, and rich host-guest chemistry have been widely studied. Adsorption-based separation methods mainly include carbon materials, zeolites, metal Organic Frameworks (MOFs), and porous organic solids. The emerging crystalline metallo-organic frameworks have excellent xenon adsorption properties due to their uniform pore size and tunable pore surface chemistry. However, since the metal-organic frameworks are mainly composed of coordination bonds, they have very poor stability under high temperature, high humidity, high irradiation conditions, especially in the case of several radioactive gases and co-existing acid gases (such as NO x, HNO3) contained during post-treatment of spent fuel. In contrast, the strongly covalently linked covalent organic frameworks have excellent chemical and thermal stability and are suitable for xenon separation under severe conditions. However, the efficiency of xenon adsorption separation of covalent organic frameworks is lower than that of representative MOFs because of their weaker polarization towards inert gases, resulting in low xenon adsorption capacity and selectivity. For xenon adsorbent systems, the inductive interactions are mainly from the electron charge on the porous solid surface. Therefore, the introduction of metal ions as accessible polar sites on the pore surface of the covalent organic framework can enhance its ability to induce xenon polarization, and can improve its adsorptive separation efficiency. Disclosure of Invention The invention aims to provide a covalent organic framework material for xenon-nitrogen separation, a preparation method and application thereof, and the prepared material has good xenon adsorption performance and xenon-nitrogen separation performance. The invention is realized by the following technical scheme: A method for preparing a covalent organic framework material for xenon nitrogen separation, comprising the steps of: firstly, preparing an hydroformylation monomer of phenanthroline; then, synthesizing a covalent organic framework by utilizing an hydroformylation monomer of the phenanthroline; And finally, according to the property of the phenanthroline, modifying the surface of the hole by using metal ions, introducing the metal ions on the covalent organic framework to adjust the surface electric field of the covalent organic framework, and promoting the selective adsorption of the covalent organic framework to xenon to obtain the covalent organic framework material for separating xenon from nitrogen. The preparation method of the phenanthroline aldehyde monomer comprises the steps of adding 3, 8-dibromo-1, 10-phenanthroline, 4-formylphenyl pinacol ester and potassium carbonate into a mixed solvent of tetrahydrofuran and deionized water according to the molar ratio of (0.5-1) (1-3) (1-4), introducing nitrogen for a period of time, adding tetra (triphenylphosphine) palladium with the molar amount of 0.05-0.3 times of that of the 3, 8-dibromo-1, 10-phenanthroline,