Preparation method for improved polyvinylidene fluoride-based nanofiltration film

A polyvinylidene fluoride-based nano-polyvinylidene fluoride technology, which is applied in the field of membrane separation, can solve problems such as the inability to guarantee the aqueous phase monomer solution and the oil phase monomer solution, and insufficient concentration stability, so as to save costs and ensure Stability, the effect of avoiding environmental pollution

Inactive Publication Date: 2018-06-01
BEIJING E & E TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although my previous research has solved the above problems, the stability of the concentration of the aqueous phase monomer solution

Method used

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Examples

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Effect test

preparation example Construction

[0021] The invention provides a method for preparing an improved polyvinylidene fluoride-based nanofiltration membrane, which is characterized in that it comprises the following steps:

[0022] (1) The polyvinylidene fluoride ultrafiltration base membrane is prepared by the phase inversion method, that is, polyvinylidene fluoride, solvents, additives, porogens, and small molecules or polymers with amino, carboxyl, sulfonic acid or hydroxyl functional groups Mix the mixture, heat it to 50-90°C and stir evenly, let it stand in a vacuum environment for defoaming to obtain the casting solution, then use a scraper to scrape the film and immerse it in the coagulation bath to form a film or flow the casting solution through the spinneret to the coagulation bath Forming a film to obtain a polyvinylidene fluoride ultrafiltration base membrane;

[0023] (2) The polyvinylidene fluoride-based nanofiltration membrane was prepared by interfacial polymerization, that is, the water phase mono...

Embodiment 1

[0034] Weigh 660g of polyvinylidene fluoride, 50g of lithium chloride, 130g of polyvinylpyrrolidone, 3160g of N,N-dimethylacetamide, and 1g of piperazine, mix and heat to 85°C and stir evenly, and stand in a vacuum environment for defoaming , to prepare the casting solution. Then the casting solution flows out into the pure water coagulation bath through the spinneret to prepare the polyvinylidene fluoride ultrafiltration base membrane; the prepared polyvinylidene fluoride ultrafiltration base membrane passes through two With thin tubes of different lengths, two peristaltic pumps were used to quantitatively inject 0.2% piperazine aqueous solution and 0.1% trimesoyl chloride n-hexane solution in the two thin tubes respectively, and the polyvinylidene fluoride was adjusted. The passing speed of the membrane and the length of the two thin tubes make the time for the aqueous phase monomer solution and the oil phase monomer solution to be coated on the polyvinylidene fluoride ultra...

Embodiment 2

[0036] Weigh 330g of polyvinylidene fluoride, 30g of lithium chloride, 64g of polyvinylpyrrolidone, 1580g of N,N-dimethylacetamide, and 0.5g of polyglutamic acid, mix and heat to 80°C and stir evenly. Place the defoaming to prepare the casting solution. Then the casting solution flows out into the pure water coagulation bath through the spinneret to prepare the polyvinylidene fluoride ultrafiltration base membrane; the prepared polyvinylidene fluoride ultrafiltration base membrane passes through two With thin tubes of different lengths, two peristaltic pumps were used to quantitatively inject 0.5% piperazine aqueous solution and 0.1% trimesoyl chloride n-hexane solution in the two thin tubes respectively, and the polyvinylidene fluoride was adjusted. The passing speed of the membrane and the length of the two thin tubes make the time for the aqueous phase monomer solution and the oil phase monomer solution to be coated on the polyvinylidene fluoride ultrafiltration membrane to...

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Abstract

The invention provides a preparation method for an improved polyvinylidene fluoride-based nanofiltration film, belonging to the technical field of films. The preparation method comprises the followingsteps: preparation of a polyvinylidene fluoride ultrafiltration base film by using a phase inversion process: mixing polyvinylidene fluoride, a solvent, an additive, a pore forming agent, and a compound having an amino, carboxyl, sulfonic acid, or hydroxyl function group, successively carrying out heating to 50-90 DEG C, uniform mixing under stirring and standing for deaeration in a vacuum environment so as to obtain a film casting solution, and then carrying out film scraping with a scraping knife and soaking in a coagulation bath for film formation or allowing the film casting solution to flow out from a spinneret to the coagulation bath for film formation so as to obtain the polyvinylidene fluoride ultrafiltration base film; and preparation of the polyvinylidene fluoride-based nanofiltration film by using an interfacial polymerization process: successively coating the surface of the polyvinylidene fluoride ultrafiltration base film with an aqueous solution of a water-phase monomerand an organic solution of an oil-phase monomer by using a quantitative injection process and then carrying out heat treatment so as to obtain the polyvinylidene fluoride-based nanofiltration film. The prepared the polyvinylidene fluoride-based nanofiltration film is stable and more cost-effective, and can avoid environmental pollution.

Description

technical field [0001] The invention relates to the technical field of membrane separation, in particular to an improved preparation method of a polyvinylidene fluoride-based nanofiltration membrane. Background technique [0002] Membrane separation technology is widely used in the separation and concentration of substances. It can be operated at room temperature and has the advantages of energy saving and environmental protection. Nanofiltration membrane technology is a kind of membrane separation technology, and it is a pressure-driven membrane technology between ultrafiltration membrane technology and reverse osmosis technology. The nanofiltration membrane has a nanometer-scale membrane pore size, and most of the membranes are charged, so the nanofiltration membrane can retain divalent or multivalent ions and organic substances with larger molecular weights during operation, while allowing monovalent ions to pass through. Therefore, based on the unique properties of nano...

Claims

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Application Information

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IPC IPC(8): B01D71/82B01D71/34B01D67/00
CPCB01D67/0006B01D67/0011B01D67/0013B01D67/0016B01D67/0088B01D67/0093B01D71/34B01D71/82
Inventor 王蕾徐愿坚韩君张如意凡祖伟
Owner BEIJING E & E TECH
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