Method for preparing high-throughput covalent organic framework nano-filtration membrane on basis of interfacial polymerization

A covalent organic framework and interfacial polymerization technology, applied in the field of porous materials and separation membranes, can solve the problems of low flux, easy detachment, and difficult scale-up preparation of COF composite membranes, so as to promote large-scale preparation, increase permeation flux, The effect of short process flow

Active Publication Date: 2018-11-27
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

1. The transfer operation of the preformed COF thin layer to the macroporous substrate is very complicated, and the large-area transfer is more difficult, making it almost impossible to scale up the preparation; 2. The thickness of the COF layer needs to be increased to ensure that the COF thin layer The structure in the transfer process is stable and not damaged, which makes the flux of the final COF composite membrane lower; 3. The preparation process still requires the use of strong polar solvents and higher temperatures, resulting in the commonly used porous polymer substrates. It cannot be used to prepare COF composite membranes; 4. After transfer, the interaction force between the COF layer and the porous substrate is weak, and it is easy to fall off and produce defects
These problems lead to the deterioration of the performance of COF composite membranes, and it is difficult to scale up the preparation

Method used

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  • Method for preparing high-throughput covalent organic framework nano-filtration membrane on basis of interfacial polymerization
  • Method for preparing high-throughput covalent organic framework nano-filtration membrane on basis of interfacial polymerization
  • Method for preparing high-throughput covalent organic framework nano-filtration membrane on basis of interfacial polymerization

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] 1) Weigh 2.04g of p-phenylenediamine (p-phenylenediamine, Pa) and dissolve it in 100 mL of deionized water to prepare a p-phenylenediamine aqueous phase solution with a mass fraction of 1.00 wt.%. Subsequently, 1.00 mL of glacial acetic acid with a mass fraction of 98 wt.% was added as a catalyst, and the mass fraction of acetic acid in the aqueous phase solution was 1.01 wt.%. Another 0.0330g 1,3,5-triformylphloroglucinol (1,3,5-triformylphloroglucinol, Tp) was weighed and dissolved in 100mL of n-hexane to prepare 1,3,5- Triformylphloroglucinol oil phase solution.

[0052] 2) The simple interfacial polymerization process such as figure 1 shown. Its steps are as follows: Polysulfone (PSF) ultrafiltration membrane base (pure water flux: 352L / (h·m 2 bar), the rejection rate of bovine serum albumin (BSA): 44%) is fixed in the membrane module that can store and discharge liquid, and remove the residual moisture on the surface of the porous carrier. Pour 20mL of the aque...

Embodiment 2

[0059] 1) Weigh 4.17g of p-phenylenediamine (p-phenylenediamine, Pa) and dissolve it in 100mL of deionized water to prepare a p-phenylenediamine aqueous phase solution with a mass fraction of 4.00wt.%. Subsequently, 14.67 g of p-toluenesulfonic acid monohydrate was added as a catalyst, and the mass fraction of p-toluenesulfonic acid in the aqueous phase solution was 11.18 wt.%. Another weighed 0.1990g of 1,3,5-triformylbenzene (1,3,5-triformylbenzene, TFB) was dissolved in 100mL of dichloromethane to prepare 1,3,5-triformylbenzene with a mass fraction of 0.15wt.%. Benzene oil phase solution.

[0060] 2) An anodic aluminum oxide (AAO) membrane with a pore size of 100 nm was selected as the porous substrate, and the reaction time was 60 s. Other operations were the same as step 2) in Example 1. Finally, a separation layer of COF-LZU1 (an imine covalent organic framework with a theoretical pore size of 1.8 nm) was formed on the alumina substrate after hydrolysis.

[0061] 3) Th...

Embodiment 3

[0065] 1) Weigh 4.08g of benzidine (BD) and dissolve it in a mixed solvent of 90mL of deionized water and 10mL of acetonitrile to prepare an aqueous solution of benzidine with a mass fraction of 4.00wt.%. Subsequently, 3.00 mL of hydrochloric acid with a mass fraction of 37 wt.% was added thereto as a catalyst, and the mass fraction of hydrochloric acid in the aqueous phase solution was 1.29 wt.%. Another weighed 0.1731g of 1,3,5-triformylphloroglucinol (1,3,5-triformylphloroglucinol, Tp) was dissolved in 100mL of mesitylene to prepare 1,3,5 - Triformylphloroglucinol oil phase solution.

[0066] 2) A polyvinylidene fluoride microfiltration membrane is selected as the porous substrate, the water phase contact time is 60 s, the reaction time is 90 s, and other operations are the same as step 2) in Example 1. Finally, a separation layer of TpBD (an imine covalent organic framework with a theoretical pore size of 2.3 nm) was formed on the polyvinylidene fluoride microfiltration m...

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Abstract

The invention provides a method for effectively preparing a high-throughput covalent organic framework (COFs) nano-filtration membrane on the basis of interfacial polymerization. The method comprisesthe following steps: sequentially applying an aqueous phase solution dissolved with polyamine monomers and an organic phase solution dissolved with polyaldehyde / polyketones monomers to the surface ofa porous carrier to carry out interfacial polymerization; diffusing the polyamine monomers in the aqueous phase solution saturated porous carrier to a water / oil interface to carry out schiff base reaction with polyaldehyde / polyketones in an organic phase, and gradually forming a covalent organic framework separating layer on the surface of the porous carrier by a conformal growth manner; and thencarrying out heat treatment on a composite membrane consisting of the separating layer and the porous carrier to enhance the binding force of the covalent organic framework separating layer and the porous carrier, and promoting crystallization and conversion of the covalent organic framework. The method not only is simple and convenient to operate and short in technological process, but also is well compatible with an existing process, thus, continuous product becomes possible, and the prepared composite membrane has high flux.

Description

technical field [0001] The invention belongs to the technical field of porous materials and separation membranes, and in particular relates to an efficient method for preparing high-throughput covalent organic framework (COFs) nanofiltration membranes based on interfacial polymerization. Background technique [0002] Covalent organic frameworks (COFs) are porous organic crystal materials with a polymer network structure formed by covalently connecting light elements such as C, H, N, B, O, and Si. The chemical bonds are strong and have good stability. sex. Compared with traditional polymer materials, it has a regular pore structure and a large specific surface area. The pore size of the covalent organic framework material is uniform, the pore is adjustable, the pore is arranged in a square, hexagonal and other arrangements, and the size of the pore can be designed according to the needs and select different types of precursors to adjust within the range of 0.7nm ~ 4.7nm . ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D67/00B01D69/10B01D69/12
CPCB01D67/0006B01D69/10B01D69/125
Inventor 汪勇王锐史贤松熊森魏明杰
Owner NANJING UNIV OF TECH
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