Permanent hydrophilic modification method for surface of porous membrane and porous membrane obtained by same

A technology of hydrophilic modification and porous membrane, which is applied in the field of porous membrane, which can solve the problems of membrane pore clogging and difficult adsorption, and achieve the effect of small pore size change

Active Publication Date: 2012-04-25
BEIJING ORIGINWATER TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this patent, since the selected vinyl alcohol compound is soluble in water, that is to say, the selected vinyl alcohol compound has good compatibility with water, so it is difficult to adsorb on the surface of the hydrophobic polyvinylidene fluoride film. Aldehyde compounds will preferentially cross-link in the membrane pores to form cross-linked products, which will cause membrane pore blockage

Method used

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  • Permanent hydrophilic modification method for surface of porous membrane and porous membrane obtained by same
  • Permanent hydrophilic modification method for surface of porous membrane and porous membrane obtained by same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] The polyvinylidene fluoride hollow fiber membrane prepared by the dry-wet method has a measured pure water flux of 750L / m 2 ·h·0.1MPa, the contact angle is 89°. Soak the polyvinylidene fluoride film in a vinyl alcohol-vinyl acetate copolymer solution, the composition of which is 0.2kg vinyl alcohol-vinyl acetate+94.8kg ethanol+5kg deionized water. The soaking temperature is 25°C, and the soaking time is 10 hours. Then take it out and dry it for 8 hours. The dried porous membrane was cross-linked by immersing in 1.0%wt glutaraldehyde aqueous solution, and the temperature of the glutaraldehyde aqueous solution was kept constant at 30°C. After 3 hours, the porous membrane was taken out and rinsed in deionized water for 1 hour. The measured pure water flux is 1300-1400L / m 2 ·h·0.1MPa, the contact angle is 55°.

Embodiment 2

[0053] Hollow fiber polyvinyl chloride membrane prepared by thermally induced phase separation, with a pure water flux of 800L / m 2 ·h·0.1MPa, the contact angle is 93°. The film is first soaked in vinyl alcohol-vinyl acetate solution, and the components of the solution are 20kg vinyl alcohol-vinyl acetate+60kg methanol+20kg deionized water. The solution temperature was kept constant at 15°C. The soaking temperature is 15°C, the film is taken out after soaking for 12 hours, and the drying time is 8 hours. Cross-linking was carried out with a glyoxal solution with a constant temperature of 15° C. and a concentration of 10% wt. After half an hour, the membrane was taken out and rinsed in deionized water for 2 hours. The measured pure water flux is 1780L / m 2 ·h·0.1MPa, the contact angle is 54°.

[0054] Example 3:

[0055] Flat-plate polypropylene nitrile membrane prepared by dry-wet method, the pure water flux is 750L / m 2 ·h·0.1MPa, the contact angle is 90°. The film was ...

Embodiment 4

[0057] Same as Example 3, the difference is that the membrane is a polyethersulfone hollow fiber membrane, and the pure water flux is 420L / m 2 ·h·0.1MPa, the contact angle is 92°, formaldehyde is replaced by borax, the mass concentration of borax is 2.0%, and the rest are the same. The measured pure water flux is 1380L / m 2 ·h·0.1MPa, the contact angle is 55°.

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Abstract

The invention relates to a permanent hydrophilic modification method for the surface of a porous membrane. The method comprises the following steps of: soaking a porous membrane with a polymer containing the solution of a vinyl alcohol chain segment, a first solvent and deionized water; evaporating to remove the solvent so that the hydrophilic polymer is adsorbed on the surface of the porous membrane and the surface of the membrane pores; and performing a cross-linking reaction with a cross-linking agent and the hydrophilic macromolecules adsorbed on the membrane surface to form a mesh-like hydrophilic polymer thin layer on the outer side of the porous membrane. Through the method provided by the invention, the flux reduction caused by pore blocking can be completely avoided, the generated hydrophilic coating is firmer, and the hydrophilic treatment effect is good.

Description

【Technical field】 [0001] The invention relates to the technical field of porous membranes. More specifically, the present invention relates to a method for permanently hydrophilic modification of the surface of a porous membrane, and also relates to a porous membrane with a permanently hydrophilic surface obtained by the method. 【Background technique】 [0002] As a new green and efficient separation technology, porous membranes have broad prospects in the field of separation. At present, membrane fouling is still the bottleneck restricting the application efficiency of separation membranes. Common porous membrane materials are mostly hydrophobic polymers, so the filtration resistance is large, and hydrophobic substances are easily adsorbed during the filtration process to cause pollution. Hydrophilic modification of porous membrane is an effective way to solve membrane fouling and reduce operating pressure. There are three main approaches for hydrophilic modification of p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D67/00B01D69/08B01D69/06B01D71/34B01D71/30B01D71/42B01D71/68B01D71/56
Inventor 陈亦力林勇吴强芮玉青
Owner BEIJING ORIGINWATER TECH CO LTD
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