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CN-121975333-A - Chemical crosslinking type metal organic framework aerogel and preparation method and application thereof

CN121975333ACN 121975333 ACN121975333 ACN 121975333ACN-121975333-A

Abstract

The invention belongs to the technical field of functional materials, and particularly relates to a chemical crosslinking type metal organic framework aerogel and a preparation method and application thereof. According to the invention, covalent bonds are utilized to drive MOFs materials and prepolymer containing trimethoxy silane to carry out self-assembly, MOFs aerogel materials are finally obtained through sol-gel formation and other methods, specifically, the prepared MOFs modified by double bonds and mercapto substances react under the initiation of ultraviolet light, so that MOFs modified by trimethoxy silane are generated, then hydrolyzed, aged and subjected to vacuum freeze drying to obtain aerogel, and the prepared aerogel has high acid and alkali resistance, high mechanical strength, high efficient adsorption capacity and high cycling stability on mercury ions, and has a relatively high application prospect.

Inventors

  • JIANG WEILING
  • HAN JING
  • XIAO MEIXIA
  • LV YING
  • MA GUOZHENG

Assignees

  • 西安石油大学

Dates

Publication Date
20260505
Application Date
20260305

Claims (10)

  1. 1. A chemically crosslinked metal organic framework aerogel comprising: a metal organic framework material modified by a double bond compound; further modifying the double bond modified metal organic framework material by (3-mercaptopropyl) trimethoxysilane to form trimethoxysilyl modified metal organic framework material; The trimethoxy silicon-based modified metal organic framework material is chemically crosslinked with a bis trimethoxy silane precursor, wherein the mass ratio of the trimethoxy silicon-based modified metal organic framework material to the bis trimethoxy silane precursor is 1:9-39; the double bond compound is selected from one or more of propylene isocyanate, methacrylic anhydride, 10-undecylenoyl chloride and 10-undecylenic aldehyde, the metal organic framework material is selected from one of IRMOF, MIL, uiO series of materials, the materials comprise IRMOF-3 and NH 2 -MIL-101、NH 2 -UiO66、NH 2 -UIO67, and the bis trimethoxysilane precursor is a compound with an alkyl chain of a carbon chain length of C4-C8 and contains at least one thioether group.
  2. 2. The chemically crosslinked metal organic framework aerogel of claim 1 wherein the bis-trimethoxysilane precursor is 3,3,10,10-tetramethoxy-2, 11-dioxo-6-thio-3, 10-disilyldodecane.
  3. 3. A method for preparing the chemically cross-linked metal-organic framework aerogel according to any one of claims 1 to 2, comprising the following steps: S1, carrying out heating reflux reaction on a metal organic frame material, a double bond compound and triethylamine in an organic solvent to obtain a double bond modified metal organic frame material; S2, reacting the double-bond modified metal organic frame material, (3-mercaptopropyl) trimethoxysilane with a photoinitiator under the initiation of ultraviolet light to obtain a trimethoxy silicon-based modified metal organic frame material; S3, mixing the trimethoxy silicon-based modified metal organic framework material with a bis trimethoxy silane precursor, adding hydrochloric acid to catalyze the gelation reaction, and performing vacuum freeze drying to obtain the aerogel.
  4. 4. The preparation method according to claim 3, wherein in the step S1, the molar ratio of the metal organic framework material, the double bond compound and the triethylamine is 1-3:8-16:1-5; in the step S2, the molar ratio of the double bond modified metal organic framework material to the (3-mercaptopropyl) trimethoxysilane to the photoinitiator is 1-5:30-90:0.05-2.
  5. 5. The preparation method of the double-bond modified metal-organic framework material is characterized in that in the step S1, the organic solvent is selected from one or more of dichloromethane, chloroform, tetrahydrofuran, N-dimethylformamide, acetone, ethyl acetate, dioxane and ethanol, the temperature of the heating reflux reaction is 40-80 ℃ and the time is 1-48 hours, and the products after the heating reflux reaction are subjected to centrifugation, washing and drying in sequence, so that the double-bond modified metal-organic framework material is obtained.
  6. 6. The preparation method of the trimethoxy silicon-based modified metal organic framework material is characterized in that in the step S2, the photoinitiator is benzoin dimethyl ether, the ultraviolet light initiation condition is that the wavelength is 365 nm, the power is 300W, the ultraviolet light is stirred for 1-6 hours under illumination, and the products of the ultraviolet light initiation reaction are subjected to centrifugation, washing and drying in sequence to obtain the trimethoxy silicon-based modified metal organic framework material.
  7. 7. The method according to claim 3, wherein in the step S3, the concentration of the hydrochloric acid solution is 0.35-0.45M.
  8. 8. The method according to claim 3, wherein in the step S3, the gelation reaction is carried out at a temperature of 50 to 100 ℃ for 3 to 6 days; Before vacuum freeze drying, the gel is soaked in ethanol for 80-100 h, and the ethanol is replaced for at least 5 times daily.
  9. 9. Use of the chemically crosslinked metal organic framework aerogel according to any one of claims 1-2 for adsorbing metal ions in sewage.
  10. 10. The use according to claim 9, wherein the metal ions comprise Hg (II), cd (II), cr (III).

Description

Chemical crosslinking type metal organic framework aerogel and preparation method and application thereof Technical Field The invention belongs to the technical field of functional materials, and particularly relates to a chemical crosslinking type metal organic framework aerogel and a preparation method and application thereof. Background The disclosure of this background section is only intended to increase the understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art. Metal Organic Frameworks (MOFs) show wide prospects in the fields of gas adsorption, catalysis, energy storage and the like due to the high specific surface area, adjustable pore channel structure and functional characteristics of the MOFs. However, most of the conventional MOFs materials are in powder form, and have the defects of poor mechanical properties, difficult processing, insufficient stability and the like, so that practical application of the conventional MOFs materials is limited. Therefore, researchers develop MOFs composite materials, wherein MOFs aerogel forms a three-dimensional porous structure through a freeze drying or supercritical drying technology, and the MOFs composite materials have the characteristics of excellent MOFs and the characteristics of aerogel such as light weight, flexibility and the like, and have great potential in application in multiple fields. However, in the prior art, the preparation of MOFs aerogel relies on physical crosslinking or simple compounding, for example, MOFs are dispersed in solutions of graphene oxide, polyvinyl alcohol and the like through a simple ultrasonic dispersion strategy, and then a composite gel material is prepared through a freeze-drying technology, so that the problems of insufficient mechanical strength, poor stability, poor conductivity, complex preparation process and the like are caused. Especially in acidic or alkaline environments, the materials are prone to collapse and MOFs are not well distributed, resulting in limited practical use. In addition, the existing MOFs aerogel has low adsorption selectivity to heavy metal ions, and especially has insufficient specific adsorption capacity to mercury ions. Therefore, there is a need for developing MOFs aerogel materials that combine high adsorption efficiency, excellent stability, and high mechanical strength. Disclosure of Invention In order to solve the problems, the invention provides a chemical cross-linked metal organic framework aerogel and a preparation method and application thereof. The preparation process is simplified, the reaction time can be shortened to be within 48 h, specifically, the metal organic framework material is reacted with the double bond-containing compound, the prepared double bond-modified MOFs and sulfhydryl substances react under the initiation of ultraviolet light to generate trimethoxy silane-modified MOFs, the MOFs are hydrolyzed and aged, and the aerogel is prepared through vacuum freeze drying, so that the uniformity, acid and alkali resistance and mechanical strength of the aerogel are obviously improved through a chemical crosslinking process, and meanwhile, the aerogel has high-efficiency adsorption and circulation stability on mercury ions and has a high application prospect. Specifically, the technical scheme of the invention is as follows: In a first aspect of the present invention, there is provided a chemically crosslinked metal organic framework aerogel comprising: a metal organic framework material modified by a double bond compound; further modifying the double bond modified metal organic framework material by (3-mercaptopropyl) trimethoxysilane to form trimethoxysilyl modified metal organic framework material; The trimethoxy silicon-based modified metal organic framework material is chemically crosslinked with a bis trimethoxy silane precursor, wherein the mass ratio of the trimethoxy silicon-based modified metal organic framework material to the bis trimethoxy silane precursor is 1:9-39; The double bond compound is selected from one or more of propylene isocyanate, methacrylic anhydride, 10-undecylenoyl chloride and 10-undecylenic aldehyde, the metal organic framework material is selected from one of IRMOF, MIL, uiO series of materials, including IRMOF-3 and NH 2-MIL-101、NH2-UiO66、NH2 -UIO67, and the bis trimethoxysilane precursor is a compound with a carbon chain length of C4-C8 and an alkyl chain containing at least one thioether group (-S-) and is preferably 3,3,10,10-tetramethoxy-2, 11-dioxo-6-thio-3, 10-disilyldodecane. The mass ratio of trimethoxy silicon-based modified metal organic framework material to bis-trimethoxy silane precursor directly affects the crosslinking density, pore structure, mechanical properties and adsorption capacity of the aerogel. Such as: If the mass ratio of MOF-MPTMS