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CN-117258560-B - Porous liquid/graphene oxide composite membrane and preparation method and application thereof

CN117258560BCN 117258560 BCN117258560 BCN 117258560BCN-117258560-B

Abstract

The invention relates to a porous liquid/graphene oxide composite membrane, a preparation method and application thereof, wherein the composite membrane is a membrane layer formed by assembling porous liquid and graphene oxide on a porous support, the porous liquid comprises a porous framework material and a steric hindrance molecule chain segment, the steric hindrance molecule chain segment comprises ionic liquid and/or crown ether, the ionic liquid is formed by pairing an anionic group and a cationic group, the anionic group comprises bis (trifluoromethanesulfonyl) imide, and the cationic group comprises imidazole and/or pyridine. The preparation method of the composite membrane is characterized in that the porous liquid is uniformly distributed and directionally arranged among two-dimensional graphene oxide membrane layers by utilizing the rich interface interaction formed by the porous liquid and the graphene oxide to induce ordered self-assembly through a simple liquid phase preparation technology, and a stable and defect-free two-dimensional graphene oxide membrane limited-domain mass transfer channel is constructed, so that the composite membrane has good ion permeability and selectivity, and can be applied to preparation of ion separation products.

Inventors

  • ZHANG MENGCHEN
  • HUANG JIANAN
  • Pang Dekang
  • LIU LINGFENG
  • JIANG LONG

Assignees

  • 五邑大学

Dates

Publication Date
20260505
Application Date
20230913

Claims (10)

  1. 1. The porous liquid/graphene oxide composite membrane is characterized by comprising a porous support body, and a porous liquid material and graphene oxide which are sequentially and alternately assembled on the porous support body; The porous liquid material comprises a porous framework material and a steric hindrance molecule chain segment combined with the porous framework material, wherein the porous framework material comprises at least one of a metal organic framework, a metal organic cage and a porous organic cage, the steric hindrance molecule chain segment comprises ionic liquid and/or crown ether, and the mass ratio of the porous framework material to the steric hindrance molecule chain segment in the porous liquid material is 1:20-1:1; the porous support is a porous ultrafiltration membrane and/or a microfiltration membrane.
  2. 2. The porous liquid/graphene oxide composite membrane of claim 1, wherein the porous liquid material is assembled on the porous support in an amount of 10-100 mg/cm2; and/or the assembly amount of the graphene oxide on the porous support is 0.1-2 mg/cm < 2 >.
  3. 3. The porous liquid/graphene oxide composite membrane according to claim 1, wherein the metal-organic framework is 2-methylimidazole zinc salt and/or zirconium 1, 4-carboxybenzene, the metal-organic cage is MOP-18, and the porous organic cage is at least one of CC1 crystal, CC3 crystal, RCC3 crystal, CC5 crystal and KACC crystal; And/or the ionic liquid in the steric molecular segment comprises an anionic group comprising bis-trifluoromethanesulfonyl imide and a cationic group comprising imidazole and/or pyridine.
  4. 4. The porous liquid/graphene oxide composite membrane of claim 1, wherein the ionic liquid in the hindered molecular segment comprises at least one of 1-butyl-3-methylimidazole bis-trifluoromethanesulfonyl imide, N-butylpyridinebis (trifluoromethanesulfonyl) imide salt; And/or the crown ether comprises at least one of 18-crown ether-6, 15-crown ether-5, dicyclohexyl-18-crown ether-6, dibenzo-18-crown ether-6, 4-carboxybenzo-21-crown ether-7.
  5. 5. The porous liquid/graphene oxide composite membrane according to claim 1, wherein the graphene oxide is a monodisperse graphene oxide nano sheet, the transverse dimension of which is 5-50 μm, the single layer rate is greater than or equal to 99%, and the oxygen content is 20% -40%.
  6. 6. The porous liquid/graphene oxide composite membrane of claim 1, wherein the porous support comprises at least one of polyacrylonitrile, polycarbonate, nylon, mixed cellulose ester, alumina, zirconia, and titania; and/or the porous support is of a sheet type or a flat plate type; And/or the porous support has an average pore size of 10 to 1000 nm.
  7. 7. The method for preparing the porous liquid/graphene oxide composite membrane according to any one of claims 1 to 6, which is characterized by comprising the following steps: (1) Preparing a porous liquid dispersion, namely combining a porous framework material with a steric hindrance molecular chain segment to obtain a porous liquid, and uniformly dispersing the porous liquid in a solvent to obtain the porous liquid dispersion; (2) Preparing graphene oxide dispersion liquid, namely uniformly dispersing graphene oxide in a solvent to obtain the graphene oxide dispersion liquid; (3) Assembling the porous liquid/graphene oxide composite membrane, namely assembling the porous liquid dispersion liquid obtained in the step (1) and the graphene oxide dispersion liquid obtained in the step (2) on a porous support, forming a membrane layer, and drying to obtain the porous liquid/graphene oxide composite membrane.
  8. 8. The method of preparing a porous liquid/graphene oxide composite membrane according to claim 7, wherein in step (1), the solvent comprises at least one of methanol, DMF, DCM, formic acid, dichloromethane, chloroform, and a methanol-water mixed solution; And/or the concentration of the porous liquid dispersion obtained in the step (1) is 0.01-0.5 mol/L; and/or, in the step (2), the solvent comprises at least one of water, DMSO, NMF, DMF, methanol, and a methanol-water mixed solution; and/or the concentration of the graphene oxide dispersion liquid obtained in the step (2) is 0.01-0.5 mg/mL.
  9. 9. The method of preparing a porous liquid/graphene oxide composite membrane according to claim 7, wherein in the steps (1) and (2), the porous liquid and the graphene oxide are uniformly dispersed in a solvent by stirring and/or ultrasonic treatment, respectively, wherein the stirring time is 10-60 min, the ultrasonic power is 100-700W, and the ultrasonic time is 5-30 min; And/or, in the step (3), the assembly mode comprises spin coating and/or filtering; the step of spin coating comprises the steps of sequentially and alternately spin-coating the porous liquid dispersion liquid and the graphene oxide dispersion liquid on a porous support body, wherein the spin-coating rotating speed is 500-2500 rpm, the single spin-coating time of each spin-coating is 30-120s, and the spin-coating cycle times are 5-60 times; The filtration step comprises the steps of uniformly stirring and mixing the porous liquid dispersion liquid and the graphene oxide dispersion liquid to obtain film forming liquid, and assembling the film forming liquid on a porous support body through pressure driving, wherein the pressure driving method is pressure filtration or vacuum suction, and the pressure difference is 0.1-1.0 MPa.
  10. 10. The use of the porous liquid/graphene oxide composite membrane according to any one of claims 1 to 6 in the preparation of ion separation products.

Description

Porous liquid/graphene oxide composite membrane and preparation method and application thereof Technical Field The invention relates to the technical field of new materials, in particular to a porous liquid/graphene oxide composite membrane, and a preparation method and application thereof. Background Ion separation is a common requirement of important industrial processes such as lithium extraction in salt lakes, waste acid recovery, brine refining, hard water softening and the like. The membrane separation technology has the outstanding advantages of high separation efficiency, high precision, low energy consumption and the like, and particularly, a two-dimensional material membrane represented by a graphene oxide membrane is rapidly developed in the field of ion separation application in recent years. But the narrow detour of the graphene oxide film severely limits its separation efficiency. The introduction of the porous framework material between graphene oxide membrane layers can increase the inter-layer spacing and provide porous channels, and is an effective means for improving the membrane permeability. However, porous framework materials tend to be less compatible with graphene oxide and tend to locally agglomerate, and the composite membranes produced are prone to non-selective defects, resulting in reduced membrane selectivity. Disclosure of Invention In order to overcome the defects of the prior art, one of the purposes of the invention is to provide a porous liquid/graphene oxide composite membrane, wherein porous frame materials are uniformly distributed and stably combined among membrane layers formed by graphene oxide composite, and the spatial structure and wall surface sites of a two-dimensional graphene oxide membrane limited-domain mass transfer channel can be accurately constructed and precisely modulated so as to realize synchronous improvement of ion permeability and selectivity of the composite membrane. One of the purposes of the invention is realized by adopting the following technical scheme: A porous liquid/graphene oxide composite membrane comprising a porous support and a porous liquid material and graphene oxide sequentially assembled on the porous support; The porous liquid material comprises a porous framework material and a steric hindrance molecule chain segment combined with the porous framework material, wherein the porous framework material comprises at least one of a metal organic framework, a metal organic cage and a porous organic cage, the steric hindrance molecule chain segment comprises ionic liquid and/or crown ether, and the mass ratio of the porous framework material to the steric hindrance molecule chain segment in the porous liquid material is 1:20-1:1; the porous support is a porous ultrafiltration membrane and/or a microfiltration membrane. Preferably, the porous liquid material is assembled on the porous support in an amount of 10-100mg/cm 2; and/or the assembly amount of the graphene oxide on the porous support is 0.1-2mg/cm 2. Preferably, in the porous framework material, the metal organic framework is 2-methylimidazole zinc salt (ZIF-8) and/or zirconium 1, 4-carboxybenzene (UiO-66), the metal organic cage is MOP-18, and the porous organic cage is at least one of CC1 crystal, CC3 crystal, RCC3 crystal, CC5 crystal and KACC crystal. The porous frame material has a micropore size, well-defined intrinsic window and a pore canal cavity, can accurately screen ions with different hydration sizes and provide a rapid mass transfer path for three-dimensional ions, and the steric hindrance molecular chain segment contains functional groups, cannot enter the pore canal of the porous frame material, can be combined with the porous frame material and the graphene oxide through covalent/non-covalent effects, so that the porous frame material is uniformly distributed among graphene oxide film layers and is stable in combination. The reasonable mass proportion is favorable for the sufficient combination and coating of the steric hindrance molecular chain segments and the porous framework material to obtain the porous liquid. The reasonable solvent selection and concentration range are favorable for the porous liquid to be well dispersed in the solvent, and local agglomeration is avoided. And/or the ionic liquid in the hindered molecular segment comprises an anionic group and a cationic group, and the anionic group comprises bis-trifluoromethanesulfonyl imide and the cationic group comprises imidazole or pyridine. The porous support can provide sufficient mechanical strength to the membrane. Too small pore size of the porous support can bring additional mass transfer resistance, affecting membrane separation efficiency. The pore diameter of the porous support body is too large, so that the material falls into the pore canal of the support body and cannot form a film, and the porous support body with the pore diameter has a good use effect. Preferably, the ionic liquid i