Method for preparing modified polyether sulfone hollow fiber membrane

Abstract

The invention relates to a method for preparing a modified polyether sulfone hollow fiber membrane. The method comprises the following steps of (1) preparation of a casting membrane liquor, namely mixing 95-99% by weight of polyether sulfone and 5-1% by weight of sulfonate polyester so as to obtain a solute, dissolving the solute into a 85-80% N,N-dimethylacetamide solvent according to weight percentage of 15-20%, heating up to 70 DEG C and stirring constantly in the dissolving process, removing bubbles in the uniform, stable and transparent solution through decompression, and preparing casting membrane liquor, wherein the molecular weight of the sulfonated polyester serving as a membrane surface modifier in the casting membrane liquor is 15000-20000; and (2) preparation of a hollow fiber membrane, namely preparing the polyether sulfone hollow fiber membrane by using spinning equipment, extruding the casting membrane liquor out from annular spinneret orifices of the spinning equipment, and forming the hollow fiber membrane in a gel slot through phase inversion. As the sulfonate polyester modifier is added into the hollow fiber membrane, the hollow fiber membrane has surface activity, is beneficial for water to wet a solid body and has lasting hydrophilia, the surface tension of water can be reduced, and the hygroscopic property of the membrane is improved.

Description

technical field [0001] The invention relates to a method for modifying and preparing a polyethersulfone hollow fiber membrane, which belongs to the technical field of polymer materials. Background technique [0002] The International Union of Theoretical and Applied Chemistry (IUPAC) defines a membrane as "a three-dimensional structure in which the size of one degree in three dimensions is much smaller than that of the other two degrees, and can carry out mass transfer through multiple driving forces". The membrane separation process uses a selective permeable membrane as the separation medium. When there is a driving force on both sides of the membrane, the raw material side components selectively permeate the membrane to achieve the purpose of separation and purification. Membrane separation process is a new and efficient separation technology. Compared with traditional separation technology, it has many outstanding advantages such as high separation precision, strong sele...

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Problems solved by technology

[0004] Polyethersulfone is a weakly polar material with strong hydrophobicity. There are two problems when it is used in the treatment of water media: one is that the surface hydrophobicity of the membrane requires high pressure to penetrate water, and power consumption Second, the surface hydrophobicity of the membrane is likely to cause organic matter and colloids to adsorb on the surface of the membrane and in the pores of the membrane, forming membrane fouling, resulting in a significant decrease in the flux of the membrane with the operation time

Hydrophilic polymer additives commonly used by researchers at home and abroad include low molecular weight polymers such as polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), polyvinyl alcohol (PVA), and polyacrylic acid (PAA). This kind of polymer is easy to fall off gradually during the process of membrane making and use, resulting in a gradual decline in the water flux and anti-organic pollution performance of the polyethersulfone membrane.

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