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A composite nanofiltration membrane based on electrospinning and self-assembly technology and its preparation method

A technology of composite nanofiltration membrane and self-assembly technology, applied in the field of composite nanofiltration membrane and its preparation, can solve the problems of low membrane flux, low porosity, shortage of resources and energy, etc., and achieve the effect of huge application prospect and excellent performance.

Inactive Publication Date: 2016-08-03
BEIJING INST OF CLOTHING TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

People have done a lot of research on the separation performance of nanofiltration membranes, mainly the separation layer of nanofiltration membranes, and they are relatively mature. However, with the rapid increase in population and the shortage of resources and energy, nanofiltration technology is facing a problem: due to these nanofiltration The supporting sublayers in the membrane are denser and have lower porosity, resulting in lower membrane flux and higher operating costs
The reason is that the pore size formed by the interlacing of electrospun nanofibers is difficult to be less than 100nm, and the casting solution can easily penetrate into the fiber pores, causing pore blocking, affecting the flux, and even failing to form a dense separation layer on the fiber surface

Method used

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  • A composite nanofiltration membrane based on electrospinning and self-assembly technology and its preparation method
  • A composite nanofiltration membrane based on electrospinning and self-assembly technology and its preparation method
  • A composite nanofiltration membrane based on electrospinning and self-assembly technology and its preparation method

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Experimental program
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preparation example Construction

[0038] (1) Preparation of nanofibrous membrane:

[0039] Dissolve a high molecular polymer suitable for water filtration in a solvent, let it stand until it is completely dissolved, and stir it magnetically for 12 hours to obtain a spinning solution, and obtain electrospun nanofibers with an adjustable diameter between 400 and 1000 nm by electrospinning membrane;

[0040] (2) Hot pressing and shaping

[0041] The nanofiber / non-woven fabric film obtained in step (1) is placed in a hot press machine for hot pressing and shaping: the hot pressing temperature is 80° C.; the pressure is 0.1-0.5 MPa; the hot pressing time is 60 s.

[0042] (3) Self-assembly modification of polyelectrolyte layers

[0043] First immerse the nanofiber / non-woven fabric membrane obtained through steps (1)-(2) into a polycation solution containing 0.201-0.215g / 300ml (adjust the pH to 3 with acetic acid) for 3-10 minutes. Afterwards, the base film is immersed in a solution containing 0.201-0.215g / 300ml ...

Embodiment 1

[0047] The preparation steps of this embodiment are as follows:

[0048] (1) Preparation of polyester (PET) nanofiber / non-woven base film by electrospinning. The solution propulsion rate during spinning is 10 μL / min, the voltage is 20 kV, the receiving distance is 20 cm, the thickness of the nanofiber layer is 50 μm, and the fiber diameter is 400-1000 nm.

[0049] (2) The nanofiber / non-woven fabric film (thickness 150 μm) obtained by electrospinning was placed in a hot press machine for hot pressing and shaping: the hot pressing temperature was 80° C.; the pressure was 0.2 MPa; the hot pressing time was 60 s.

[0050] (3) Immerse the hot-pressed nanofiber / non-woven fabric membrane into chitosan polycation solution (concentration: 0.201g / 300ml, adjust pH to 3 with acetic acid) for 3min, and then immerse it in sodium alginate polyanion solution ( The concentration is 0.201g / 300ml) for 3 minutes. Repeat the above steps 3 times, and then let the membrane dry naturally at room te...

Embodiment 2

[0054] The preparation steps of this embodiment are as follows:

[0055] (1) Electrospinning to prepare polyvinylidene fluoride (PVDF) nanofiber / non-woven base film. The propulsion rate of the solution during spinning is 10 μL / min, the voltage is 20 kV, the receiving distance is 20 cm, the thickness of the nanofiber layer is 50 μm, and the fiber diameter is 400-1000 nm.

[0056] (2) The nanofiber / non-woven membrane (175 μm in thickness) obtained by electrospinning was placed in a hot press for hot pressing and shaping: the hot pressing temperature was 100° C.; the pressure was 0.2 MPa; and the hot pressing time was 60 s.

[0057] (3) Immerse the hot-pressed nanofiber / non-woven fabric membrane in chitosan polycation solution (concentration is 0.201g / 300ml, adjust pH to 3 with acetic acid) for 7min, and then immerse it in polyacrylic acid polyanion solution (concentration 0.201g / 300ml) 7min. Repeat the above steps 3 times, and then let the membrane dry naturally at room temper...

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Abstract

The invention relates to a composite nanofiltration membrane based on electrospinning and self-assembly technology and a preparation method thereof, belonging to the technical field of membrane separation. The composite film has a three-layer composite structure, the top layer is an ultra-thin and dense separation layer, the middle is an electrospun nanofiber layer modified by layer-by-layer self-assembly, and the bottom layer is a non-woven support layer. The present invention uses polyelectrolyte layer-by-layer self-assembly technology to modify the surface of the electrospun nanofiber membrane, reduces the pore size of the surface of the nanofiber membrane, and combines phase transition technology to prepare a new type of nanofiltration membrane. The membrane uses a nanofiber membrane layer It replaces the porous sublayer of the traditional membrane and retains its ultra-thin and dense separation layer on the surface. The polyelectrolyte layer-by-layer self-assembly modification method involved in the present invention effectively solves the problem of the casting liquid permeating the nanofiber layer, and the prepared nanofiltration membrane has the characteristics of energy saving and high flux, and is suitable for desalination of brackish water, ultra-pure Water preparation and other fields have great application prospects.

Description

technical field [0001] The invention relates to a composite nanofiltration membrane and a preparation method thereof, in particular to a composite nanofiltration membrane based on electrospinning and self-assembly technology and a preparation method thereof, and uses polyelectrolyte layer-by-layer self-assembly (LBL) technology to modify electrospinning Nanofibers, combined with phase transitions to prepare composite nanofiltration membranes, belong to the technical field of membrane separation. Background technique [0002] The specific definition of nanofiltration membrane is that the operating pressure is not greater than 1.50MPa, the molecular weight cut-off is between 200 and 1000, and the rejection rate of NaCl is not more than 90%. The membrane can be regarded as a nanofiltration membrane. Nanofiltration is a new type of separation process developed in the middle and late 1970s. It has different selectivities for monovalent and divalent ions, and has a high rejection ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D69/12B01D71/68B01D71/34B01D71/42B01D67/00
Inventor 王娇娜李从举章淼鑫
Owner BEIJING INST OF CLOTHING TECH