Hydrophilicity kynoar hollow fiber microporous membrane and preparation method thereof

Abstract

The invention discloses a hydrophilic polyvinylidene fluoride hollow fiber microporous membrane and the preparation method thereof. The main composition and the mass content of the membrane are 70% to 90% of polyvinylidene fluoride, amphiphilic poly-(propylene oxide-oxirane), 5% to 29% of poly-(methacrylic acid- acrylic acid) or poly-(methacrylic acid methyl ester-vinyl alcohol) copolymer and 1% to 5% of nano-silicon dioxide. The membrane preparation method is that all the components are mixed and dissolved with aperture regulator, thickener and solvent to obtain the membrane preparation liquid; after that, the hollow fiber forming is carried out through a dry-wet spinning technique, and finally cleaning and drying are implemented. The obtained membrane has adjustable internal diameter and external diameter, 60% to 80% of porosity and the aperture ranging from 0.01micron to 0.2micron. As a water disposal separating membrane material with excellent performance, the invention has the advantages of being able to be fully humid, organic adsorption resistance and great water flux, etc.

Description

technical field [0001] The invention belongs to the technical field of separation membrane materials and membrane separation, and in particular relates to hydrophilic polyvinylidene fluoride hollow fiber membranes suitable for water treatment and their preparation methods. Background technique [0002] As a new type of separation technology, membrane separation technology has been widely used in medicine, chemical industry, energy, food, environmental engineering and other fields due to its advantages of low energy consumption, good separation performance and no secondary pollution in use. . The selection of separation membrane materials with excellent performance is the starting point and core of membrane separation technology, and it is also the direction and focus of membrane separation technology research and development. Separation membrane materials are mostly polymers, mainly modified fibers, polyethylene, polypropylene, polyvinyl chloride, polyethersulfone, polysulf...

AI Technical Summary

Problems solved by technology

[0003] Compared with other membrane materials, the most prominent feature of PVDF is low surface energy and strong hydrophobicity. These properties make PVDF microporous membranes have good advantages in hydrophobic membrane processes such as membrane extraction and membrane distillation. When used as a water treatment membrane, the inherent strong hydrophobicity of PVDF will cause two problems: one is that it is easy to cause adsorption pollution, and when separating oil / water systems (especially solutions containing proteins), the membrane flux and rejection rate are two The main separation index will be significantly reduced, and the service life of the membrane will be shortened; the second is that the separation process requires a large driving force. The test shows that the PVDF microfiltration membrane with an average pore size of 0.2 μm is almost impervious to water under a pressure difference of 0.1MPa.

In summary, these deficiencies are mainly manifested as follows: membrane surface modification often changes the pore size and pore size distribution on the membrane surface to a certain extent; physical adsorption method only makes hydrophilic polymers adsorb on the membrane surface or inside through physical adsorption, The hydrophilic agent is easily lost during recycling, causing the hydrophilicity to not be maintained for a long time; chemical modification often affects the strength of the separation membrane to a certain extent, and the treatment conditions are relatively harsh; although the graft polymerization method can use functional groups Covalent bonds are fixed, but the treatment process is often complicated, and the grafted hydrophilic groups often move into the membrane matrix under the action of chain movement, resulting in a decrease in hydrophilicity, etc.; the hydrophilicity used in the bulk Poor polyvinylpyrrolidone loss, poor compatibility between sulfonated polyetheretherketone or cellulose and PVDF, poor long-term stability of membrane structure, etc.

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