CN-121975180-A - Pore-diameter-adjustable metal organic framework composite material and preparation method and application thereof

Abstract

The invention discloses a metal organic frame composite material with adjustable aperture, a preparation method and application thereof, relates to the technical field of functional material preparation, and aims to overcome the defects that the existing metal organic frame is low in mechanical strength and difficult to form, a structure of a cellulose nanocrystal is easy to damage by direct embedding, and aperture regulation is complex, and the method comprises the following steps: mixing an aqueous solution containing ferrous ions with a cellulose nanocrystal aqueous dispersion to form a composite dispersion system, adding vegetable oil to form an emulsion template through high-speed shearing and ultrasonic emulsification, adding an alkaline aqueous solution of trimesic acid into the emulsion template to carry out in-situ coordination reaction, carrying out solid-liquid separation, washing and drying on a reaction product, and regulating the size of emulsion template liquid drops by changing the concentration of cellulose nanocrystals to realize the regulation and control of the aperture of the composite material. The invention realizes accurate regulation and control of the pore diameter of the material, the synthetic process is environment-friendly, the mechanical strength and the formability of the material are improved, the thymol is stably adsorbed, and the application prospect in the fields of fruit and vegetable fresh-keeping and the like is wide.

Inventors

• SONG GE
• Bai Chenyu
• XU BO
• WU QI

Assignees

• 中国农业大学

Dates

Publication Date

20260505

Application Date

20260407

Claims (9)

1. 1. The preparation method of the metal organic framework composite material with the adjustable aperture is characterized by comprising the following steps of: s1, mixing an aqueous solution containing ferrous ions with a cellulose nanocrystal aqueous dispersion to form a composite dispersion system; s2, adding vegetable oil into the composite dispersion system obtained in the step S1, and forming an emulsion template through high-speed shearing and ultrasonic emulsification treatment; S3, adding an alkaline aqueous solution of trimesic acid into the emulsion template obtained in the step S2 to carry out in-situ coordination reaction; And S4, carrying out solid-liquid separation, washing and drying on the reaction product obtained in the step S3 to obtain the metal-organic framework composite material with the hierarchical pore structure.
2. 2. The method for preparing a pore-size-adjustable metal-organic framework composite material according to claim 1, wherein in S1, the ferrous ion-containing aqueous solution is a ferrous chloride tetrahydrate aqueous solution.
3. 3. The method of preparing a pore size tunable metal-organic framework composite according to claim 1, wherein the mass percentage concentration of cellulose nanocrystals in the aqueous phase volume of the emulsion template is 1.5-1.75 g/100mL.
4. 4. The method for preparing a pore size adjustable metal-organic framework composite material according to claim 1, wherein in the step S2, the vegetable oil is corn oil, and the volume ratio of the vegetable oil to the composite dispersion system is 1 (8-12).
5. 5. The method for preparing a metal-organic framework composite material with adjustable pore diameter as claimed in claim 1, wherein in the step S3, the molar ratio of ferrous ions to trimesic acid is (1.2-1.8): 1.
6. 6. A composite material prepared by the method of any one of claims 1-5.
7. 7. An antibacterial material, characterized in that the antibacterial material is formed by loading thymol by the composite material of claim 6.
8. 8. The antibacterial material according to claim 7, wherein the composite material is immersed in a thymol ethanol solution, subjected to vibration adsorption for 24-36 hours, and then washed and dried, so that the antibacterial material is obtained.
9. 9. Use of the antibacterial material according to claim 7 for non-contact fruit and vegetable fresh-keeping.

Description

Pore-diameter-adjustable metal organic framework composite material and preparation method and application thereof Technical Field The invention relates to the technical field of composite materials. More particularly, the invention relates to a metal organic framework composite material with adjustable aperture, a preparation method and application thereof. Background Metal organic framework Materials (MOFs) are used as a crystal material formed by self-assembly of metal ions and organic ligands, and have wide application prospects in the fields of adsorption, catalysis, medicine loading and the like by virtue of the ultra-large specific surface area, high porosity and excellent chemical and thermal stability. However, most of the existing metal organic frame materials are in powder or microcrystal forms, the internal porosity is high, so that the inter-particle binding force is weak, the mechanical strength is low, the brittleness is high, direct forming processing is difficult, and the stability and applicability of the metal organic frame materials in actual scenes are severely limited. Pore size regulation is a key to expanding the application range of metal organic framework materials, and the requirements of different scenes (such as small molecule adsorption, bioactive substance loading and the like) on the pore size of the materials are obviously different. The traditional aperture regulation and control method depends on complex ligand design or toxic organic solvents, is complex in operation and high in cost, has the problem of insufficient environmental friendliness, and is difficult to meet the development trend of green synthesis. Cellulose is taken as a natural green material with wide sources, and Cellulose Nanocrystals (CNC) obtained through nanocrystallization have good biocompatibility, high length-diameter ratio and rich surface active sites, and are considered as ideal substrates for improving the performances of metal-organic framework materials. However, because cellulose nanocrystals have a rigid rod-like structure, they are easily embedded or mixed into metal organic framework crystals when directly used as a growth substrate, and the ordered structure and coordination environment of the crystals are destroyed, thus failing to fully exert their reinforcing effect. The emulsion template method is an effective technology for preparing porous materials, but the traditional system adopts surfactant to stabilize emulsion, has the defects of poor stability, insufficient biocompatibility and the like, and is difficult to realize the accurate regulation and control of the aperture and the synchronous improvement of the mechanical properties of the materials. Meanwhile, in the fields of food preservation and the like, although the natural antibacterial agent (such as an antibacterial active ingredient derived from plant essential oil) has the advantages of safety and high efficiency, the natural antibacterial agent is easily inactivated due to the influence of environmental factors, and a carrier material with good loading capacity, structural stability and green characteristics is needed to solve the problem. Therefore, there is a need to design a solution that overcomes the above drawbacks. Disclosure of Invention The invention aims to provide a metal organic framework composite material with adjustable pore diameter, a preparation method and application. To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a method for preparing a metal organic frame composite material having an adjustable pore size, comprising S1 mixing an aqueous solution containing ferrous ions with an aqueous dispersion of cellulose nanocrystals to form a composite dispersion, S2 adding vegetable oil to the composite dispersion obtained in S1, performing high-speed shearing and ultrasonic emulsification to form an emulsion template, S3 adding an alkaline aqueous solution of trimesic acid to the emulsion template obtained in S2, performing in-situ coordination reaction, and S4 subjecting the reaction product obtained in S3 to solid-liquid separation, washing and drying to obtain a metal organic frame composite material having a multi-stage pore structure. Further, in S1, the aqueous solution containing ferrous ions is a ferrous chloride tetrahydrate aqueous solution. Further, the mass percentage concentration of the cellulose nanocrystals in the aqueous phase volume of the emulsion template is 1.5-1.75 g/100mL. Further, in S2, the vegetable oil is corn oil, and the volume ratio of the vegetable oil to the composite dispersion system is 1 (8-12). Further, in S3, the molar ratio of the ferrous ion to trimesic acid is (1.2-1.8): 1. According to another aspect of the present invention, a composite material is also provided. According to another aspect of the invention, there is also provided an antibacterial material c