Method for preparation of polyvinylidene fluoride membrane by complex thermally induced phase separation

A technology of polyvinylidene fluoride membrane and thermally induced phase separation, which is applied in semipermeable membrane separation, chemical instruments and methods, membrane technology, etc., and can solve problems such as unsatisfactory effect of ultra-microfiltration membrane and inability to meet the needs of industrial production , to achieve the effect of reducing production costs

Inactive Publication Date: 2013-08-21
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the effect of most commercial ultrafiltration membranes is not satisfactory at present, and cannot meet the needs of industrial production.

Method used

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  • Method for preparation of polyvinylidene fluoride membrane by complex thermally induced phase separation
  • Method for preparation of polyvinylidene fluoride membrane by complex thermally induced phase separation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Step 1: Accurately weigh 255.032g of caprolactam, 45.012g of PVDF, and the mass fraction of PVDF is 15%. Stir the powder evenly and pour it into a 500ml beaker. The temperature of the oil bath used is 115°C. Heat the beaker under nitrogen protection until the caprolactam and The PVDF mixed powder was completely melted for 0.5 h, then the solution was stirred with an electric stirrer for 30 min, then stood in an oil bath for 20 min, and finally the beaker was naturally cooled to room temperature.

[0024] Step 2: Put the membrane solution obtained in Step 1 in a vacuum oven at a temperature of 115° C. to remelt the blend of caprolactam and PVDF.

[0025] Step 3: The membrane solution obtained in Step 2 was scraped to form a membrane, quickly placed in 10°C water, and the caprolactam was extracted for 48 hours to obtain a PVDF membrane.

[0026] The PVDF measured by this method has a flux of 1512.59L / m to pure water at 25°C 2 h,

Embodiment 2

[0028] Step 1: Accurately weigh 240.017g of caprolactam, 60.007g of PVDF, and the mass fraction of PVDF is 20%. Stir the powder evenly and pour it into a 500ml beaker. The temperature of the oil bath used is 130°C. Heat the beaker under nitrogen protection until the caprolactam and PVDF The mixed powder was completely melted for 0.7 h, then the solution was stirred with an electric stirrer for 30 min, then left to stand in an oil bath for 20 min, and finally the beaker was naturally cooled to room temperature.

[0029] Step 2: Put the membrane solution obtained in Step 1 in a vacuum oven at a temperature of 130° C. to remelt the blend of caprolactam and PVDF.

[0030] Step 3: Scrape the film obtained in step 2 into a film, quickly place it in water at 10°C, and extract the caprolactam in it. The extraction time is 48 hours to obtain a PVDF film. The SEM image of the formed film is as follows figure 2 shown.

[0031] The PVDF measured by this method has a pure water flux of 1...

Embodiment 3

[0033] Step 1: Accurately weigh 225.021g of caprolactam, PVDF.75.005g, and the mass fraction of PVDF is 25%. Stir the powder evenly and pour it into a 500ml beaker. The temperature of the oil bath used is 140°C. Heat the test tube under nitrogen protection until the caprolactam and The PVDF mixed powder was completely melted for 0.8 hours, then the solution was stirred with an electric stirrer for 30 minutes, and then stood in an oil bath for 20 minutes, and finally the beaker was naturally cooled to room temperature.

[0034] Step 2: Put the membrane liquid obtained in Step 1 in a vacuum oven at a temperature of 140°C to remelt the blend of caprolactam and PVDF.

[0035] Step 3: The membrane solution obtained in Step 2 was scraped into a membrane, quickly placed in 10°C water, and the caprolactam was extracted for 48 hours to obtain a PVDF membrane.

[0036] The flux of PVDF to 25°C pure water measured by this method is 39.76L / m 2 h

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Abstract

The invention relates to a method for preparation of a polyvinylidene fluoride (PVDF) membrane by complex thermally induced phase separation. The method comprises the steps of: 1) preparation of a membrane casting solution: weighing 65%-85% of caprolactam and 15%-35% of polyvinylidene fluoride, mixing them uniformly, heating the mixture in oil bath to 115DEG C-170DEG C for 0.5h-2h under nitrogen protection to make the caprolactam and polyvinylidene fluoride dissolved, then performing constant temperature stirring for 0.5h-1.5h, and conducting standing to obtain a standard membrane casting solution, leaving the membrane casting solution to natural cooling so as to obtain a solid mixture; 2) membrane formation: placing the solid mixture into a vacuum oven and heating it to 115DEG C-170DEG C to remelt it, then carrying out membrane scraping by a membrane scraper; and 3) gel membrane formation: placing the scraped nascent state membrane into water or ethanol quickly, and conducting extraction to obtain the polyvinylidene fluoride membrane. The method provided in the invention takes caprolactam as a solvent to prepare the membrane by complex thermally induced phase separation, and has the characteristics of simple process and no pollution. The prepared PVDF membrane has chemical stability and high strength, and can provide high performance membrane products for an MBR process.

Description

technical field [0001] The patent of the invention belongs to the field of membrane manufacturing. Specifically, it relates to the preparation of a polyvinylidene fluoride membrane by using a new solvent through a composite thermal phase separation method. The prepared porous membrane can be used in the fields of environmental protection and water treatment. Background technique [0002] With the development of social economy and urbanization, the shortage of water resources and the pollution of water environment have become global problems in this century and are becoming more and more serious. The water crisis caused by the shortage of water resources and water environment pollution has also become an important restrictive factor for the development of our country's society and economy. [0003] Membrane bioreactor (MBR) is a new type of efficient sewage treatment technology, which can realize biocatalytic reaction and separation of water and degraded substances at the sam...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/34
Inventor 肖通虎卢季覃海娇
Owner NINGBO UNIV
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