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Preparation method of hydrophilic ethylene/vinyl alcohol copolymer composite flat plate ultrafiltration membrane

A technology of copolymer and vinyl alcohol, which is applied in the field of preparing hydrophilic EVOH composite flat membrane by phase inversion method, can solve the problems of low strength, low stiffness, hydrophobicity and easy pollution, etc., achieve performance improvement, reduce membrane production cost, and process simple and easy effects

Active Publication Date: 2015-07-15
陕西省膜分离技术研究院有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to address the problems of hydrophobicity and easy pollution in the application of separation membranes (including composite membranes) prepared from existing membrane main materials, and the low strength and low strength of separation membranes prepared from ethylene / vinyl alcohol copolymers. For low stiffness defects, the immersion precipitation phase inversion film making process is combined with the concept of composite film, and the casting solution with ethylene-vinyl alcohol copolymer as the main material is coated on the surface of polyester non-woven fabric, and then transformed into membrane
This method effectively solves the thorny problems of using ethylene-vinyl alcohol copolymer as the main material to prepare ultrafiltration membranes and traditional membrane materials, and obtains a hydrophilic ethylene / vinyl alcohol copolymer composite flat ultrafiltration membrane

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Mix 10wt% ethylene / vinyl alcohol copolymer (20% ethylene content), 3wt% β-cyclodextrin, 3wt% polyethylene glycol, 2wt% LiCl in 2wt% acetone + 80wt% dimethyl ethyl alcohol In the amide organic solvent, stir and dissolve at 40°C for 8h, and stand at 40°C for 2h to defoam to obtain a homogeneous casting solution.

[0021] Fix the polyester non-woven fabric on the smooth and flat surface of the glass plate, and then evenly coat the prepared homogeneous casting solution on the surface of the polyester non-woven fabric with a scraper rod. After pre-evaporating in the air for 30 seconds, put It was placed in a water bath at 60°C for phase inversion to form a film. After the phase inversion, the membrane was fully rinsed in tap water to remove the organic solvent remaining on the surface of the membrane, and then placed in deionized water for 24 hours to obtain an ethylene / vinyl alcohol copolymer composite flat ultrafiltration membrane.

[0022] The pure water flux of the obta...

Embodiment 2

[0024] Mix 16wt% ethylene / vinyl alcohol copolymer (27% ethylene content), 2wt% acrylic acid, 3wt% polyethylene glycol, 2wt% cetyltrimethylammonium bromide in 2wt% acetone + 75wt % dimethylformamide organic solvent, stirring and dissolving at 30°C for 24h, standing at 30°C for degassing for 2h, to obtain a homogeneous casting solution.

[0025] Fix the polyester non-woven fabric on a smooth and flat glass plate surface, and then use a film scraper to evenly coat the prepared homogeneous casting solution on the surface of the polyester non-woven fabric. After pre-evaporating in the air for 10 seconds, Place it in a water bath at 0°C for phase inversion to form a film. After the phase inversion, the membrane was fully rinsed in tap water to remove the organic solvent remaining on the surface of the membrane, and then placed in deionized water for 24 hours to obtain an ethylene / vinyl alcohol copolymer composite flat ultrafiltration membrane.

[0026] The pure water flux of the ob...

Embodiment 3

[0028] Mix 10wt% ethylene / vinyl alcohol copolymer (38% ethylene content), 1wt% β-cyclodextrin in 2wt% acetone + 87wt% N-methylpyrrolidone organic solvent, stir and dissolve at 30°C for 36h , standing at 30°C for degassing for 6 hours to obtain a homogeneous casting solution.

[0029] Fix the polyester non-woven fabric on a smooth and flat glass plate surface, and then evenly coat the prepared homogeneous casting solution on the surface of the polyester non-woven fabric with a scraper rod, and pre-evaporate in the air for 30 seconds, Place it in a water bath at 0°C for phase inversion to form a film. After the phase inversion, the membrane was fully rinsed in tap water to remove the organic solvent remaining on the surface of the membrane, and then placed in deionized water for 24 hours to obtain an ethylene / vinyl alcohol copolymer composite flat ultrafiltration membrane.

[0030] The pure water flux of the gained ethylene / vinyl alcohol copolymer composite flat ultrafiltration...

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Abstract

The invention discloses a preparation method of a hydrophilic ethylene / vinyl alcohol copolymer composite flat plate ultrafiltration membrane. Principles of an immersion-precipitation phase inversion process are adopted for coating an ethylene / vinyl alcohol copolymer solution on the surface of polyester non-woven fabric and forming the membrane in a water bath by phase inversion. The specific preparation steps are as follows: 1) stirring and dissolving an ethylene / vinyl alcohol copolymer, additives and an organic solvent according to a certain proportion to prepare a homogeneous membrane casting solution for later use; 2) fixing the polyester non-woven fabric on the surface of a smooth and flat glass plate, and uniformly coating the obtained membrane casting solution on the surface of the polyester non-woven fabric; and 3) placing the polyester non-woven fabric in the water bath for forming the membrane by phase inversion, and further obtaining the high-strength, hydrophilic and anti-pollution ethylene / vinyl alcohol copolymer composite flat plate ultrafiltration membrane. The method is simple and easy to operate and has strong operatability, and the hydrophilic composite membrane can be obtained by using the hydrophilic ethylene / vinyl alcohol copolymer as a membrane main material.

Description

technical field [0001] The invention belongs to the field of separation membrane preparation, and mainly relates to a method for preparing a hydrophilic EVOH composite flat membrane by a phase inversion method. Background technique [0002] In recent decades, ultrafiltration technology has been widely used in natural water treatment, urban sewage regeneration and other processes due to its advantages of low energy consumption, high efficiency, and no need for chemical pretreatment. However, in the promotion and application of ultrafiltration membranes, the main problem is the membrane fouling problem that causes the membrane performance to decay continuously. Many research results show that one of the root causes of ultrafiltration membrane pollution is that the organic matter in actual wastewater is mainly hydrophobic natural organic matter and hydrophobic humic pollutants, while ultrafiltration membranes currently used in wastewater treatment (including Composite membrane...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/38B01D69/12B01D69/06B01D67/00
Inventor 王磊苗瑞蔡巧云王旭东吕永涛冯玲刘紫文容志勇
Owner 陕西省膜分离技术研究院有限公司