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CN-121972031-A - Method for synthesizing and regulating MOF pervaporation membrane through liquid-liquid interface

CN121972031ACN 121972031 ACN121972031 ACN 121972031ACN-121972031-A

Abstract

A method for synthesizing and regulating MOF pervaporation membrane at liquid-liquid interface relates to the field of pervaporation membrane. The method comprises the steps of providing a metal salt dispersion liquid prepared by a proper solvent, providing an organic ligand aqueous solution, adding a surfactant into the organic ligand solution, changing interfacial tension to regulate nucleation and growth behaviors of MOF particles at a liquid-liquid interface, regulating and controlling a deprotonation process of the organic ligand by adding a deprotonating agent into the organic ligand solution, thereby accelerating the reaction rate to realize precise regulation and control of morphology and size of the MOF film, and obviously improving the film forming rate and film quality by the synergistic effect of multiple regulating and controlling mechanisms.

Inventors

  • LI JIE
  • WANG YIXIAN
  • ZHAO HANQING
  • WANG JINGXIU
  • WANG NAIXIN
  • GUO HONGXIA
  • AN QUANFU

Assignees

  • 北京工业大学

Dates

Publication Date
20260505
Application Date
20260316

Claims (10)

  1. 1. A method for rapidly generating a continuous MOF film at a liquid-liquid interface, which is characterized by comprising the following technical scheme: (1) Providing a metal salt dispersion formulated with a suitable solvent; (2) Providing an organic ligand aqueous solution, and regulating and controlling nucleation and growth behaviors of MOF particles at a liquid-liquid interface by adding a surfactant into the organic ligand aqueous solution and changing interfacial tension, or regulating and controlling a deprotonation process of the organic ligand by adding a deprotonating agent into the organic ligand aqueous solution, so that the reaction rate is accelerated, and the morphology and the size of the MOF film are accurately regulated and controlled; (3) And (3) smoothly dripping the metal salt dispersion liquid in the step (1) onto the surface of the organic ligand aqueous solution, and standing for a period of time, wherein the MOF generates an integral membrane structure at a liquid-liquid interface in the process.
  2. 2. The method of claim 1, wherein the dispersion of metal salts comprises a metal salt and a dispersant; The dispersing agent is at least one selected from N-octanol, isopropanol, N-butanol, N-2 methylacetamide and N-propanol, and the isopropanol and the N, N-2 methylacetamide are not independently used; The metal salt is at least one selected from cobalt nitrate hexahydrate, zinc nitrate, copper nitrate, nickel nitrate, zirconium chloride and ferric chloride; In the dispersion liquid with the metal salt, the mass concentration of the metal salt is 0.1-15%.
  3. 3. The method according to claim 1, wherein the organic ligand is selected from 2-methylimidazole, and the mass concentration of the organic ligand is 0.1% -2%.
  4. 4. The method according to claim 1, wherein the surfactant is selected from octadecyl diethyl silane, cetyl trimethyl ammonium chloride and cetyl trimethyl ammonium bromide, and the mass concentration of the surfactant is 0.027% -1.35%.
  5. 5. The method according to claim 1, wherein the proton removing agent in the organic ligand solution is sodium bicarbonate or ammonia water, and the mass concentration of the proton removing agent is 0.04% -1%.
  6. 6. The method according to claim 1, characterized in that 150ml of a 2-methylimidazole solution with a mass concentration of 1.5% is poured into a 100mm x 50mm crystallization dish, 2000 μl of the dispersion with cobalt nitrate hexahydrate is slowly dropped onto the surface of the 2-methylimidazole solution by a pipette gun along the edge, and left to stand for 40min.
  7. 7. The method according to claim 1, wherein the base film is immersed in the aqueous organic ligand solution obtained in the step (2) in advance, and after the MOF film is formed, the base film is slowly lifted up so that the formed MOF film is transferred onto the base film, or the formed MOF film is transferred by dropping the lower layer solution from below the liquid-liquid interface onto the base film, and the composite film is obtained by drying.
  8. 8. The method of claim 7, wherein the base film comprises at least one of an organic base film, an inorganic base film, and a silicon wafer.
  9. 9. A MOF film prepared according to the method of any one of claims 1-8.
  10. 10. Use of a MOF membrane prepared according to the method of any one of claims 1 to 8 as a pervaporation alcohol-preferential membrane.

Description

Method for synthesizing and regulating MOF pervaporation membrane through liquid-liquid interface Technical Field The invention relates to the field of pervaporation membranes, in particular to a related formula for synthesizing and regulating a continuous complete MOF membrane at a liquid-liquid interface. Background Metal organic framework Materials (MOFs) and derivatives thereof exhibit great potential for use in the fields of gas storage, adsorptive separation, electro/photochemical sensing techniques, wearable devices, and catalysis. For these applications, it is particularly important to regulate the integrity of the MOF film and the size and morphology of the crystals. As a new class of crystalline porous materials, various types of MOFs have been reported, such as MOF-5, ZIFs (zeolitic imidazoles), MIL series, uiO-66, HKUST-1, PCN-222, etc., but at the same time there are some limitations including synthesis complexity, stability problems, high cost, regulatory difficulties, selectivity and flux limitations, and processing difficulties. In the related art, metal Organic Framework (MOF) films are typically prepared on a substrate, including solvent/hydrothermal methods, liquid phase epitaxy, back diffusion, rapid thermal deposition, dip-coating-thermal conversion, electrochemical deposition, interfacial microfluidic technology film processing, gel-vapor deposition, ligand induction, and the like. However, the MOF film obtained in the related art is difficult to directly and uniformly nucleate on the porous substrate, so that the MOF film has large defects and cracks, the continuity and uniformity of the film are difficult to ensure, and the size and the morphology of the film cannot be well regulated. Some researchers salvage the membrane by synthesizing particles at the liquid-liquid interface and then using a base membrane, but most of the particles are simply accumulated, and organic matters are required to cover the surface of the MOF membrane to make up for the defects so as to ensure the continuous densification of the membrane. The invention can directly synthesize the continuous MOF membrane at the liquid-liquid interface by regulating and controlling parameters such as interfacial tension, diffusion rate, reaction rate and the like, and is applied to the field of pervaporation preferential alcohol permeation, thereby improving separation factors. Disclosure of Invention The invention provides a formula for rapidly generating a continuous MOF film at a liquid-liquid interface, which can solve the technical problems of film defects and the like in the related technology. Specifically, the method comprises the following technical scheme: (1) Providing a proper solvent to prepare a metal salt dispersion liquid corresponding to MOF; (2) Providing an organic ligand aqueous solution corresponding to MOF, and changing interfacial tension to regulate nucleation and growth behaviors of MOF particles at a liquid-liquid interface by adding a surfactant into the organic ligand aqueous solution, or regulating the deprotonation process of the organic ligand by adding a deprotonating agent into the organic ligand aqueous solution, so that the reaction rate is accelerated to realize precise regulation and control of the morphology and the size of the MOF film; (3) The metal salt dispersion in step (1) is smoothly dropped onto the surface of the aqueous solution of the organic ligand (preferably along the edge of the container), and left for a period of time, during which the MOF forms an integral membrane structure at the liquid-liquid interface. Wherein the dispersion with metal salt in step (1) comprises a metal salt and a dispersant; the dispersing agent is at least one selected from N-octanol, isopropanol, N-butanol, N-2 methylacetamide, N-propanol and N-heptane, and the isopropanol and the N, N-2 methylacetamide are not independently used, and the preferable volume ratio of the N-butanol to the isopropanol is 3:1. The metal salt is selected from cobalt nitrate hexahydrate, zinc nitrate, copper nitrate, nickel nitrate, zirconium chloride and ferric chloride. In the metal salt dispersion liquid, the mass concentration of the metal salt is 0.1% -15%. In the organic ligand aqueous solution, the solvent is deionized water, and the mass concentration of the organic ligand is 0.1% -2%. The organic ligand in step (2) is selected from 2-methylimidazole. The surfactant is selected from octadecyl diethyl silane, cetyl trimethyl ammonium chloride and cetyl trimethyl ammonium bromide, and the mass concentration of the surfactant is 0.027% -1.35%. The proton removing agent is sodium bicarbonate and ammonia water, the mass concentration of the proton removing agent is 0.04% -1%, and the proton removing agent is added into the water phase containing the organic ligand. The base film comprises at least one of an organic base film, an inorganic base film and a silicon wafer. The MOF film is formed by extending an MOF pre