Pressureless polyethersulfone hollow fiber film with highly-asymmetric spongy structure

Abstract

The invention provides a pressureless polyethersulfone hollow fiber film with a highly-asymmetric spongy structure. The pressureless polyethersulfone hollow fiber film is prepared by preparing a transparent, uniform and stable film casting liquid from polyethersulfone, an organic polar solvent, a hydrophilic second polymer and an organic micromolecular additive, extruding the film casting liquid from an annular gap via the spinning head of a molding spinning device, spraying gas used as an internal diameter maintenance agent through the center tube of the spinning head so as to prepare a hollow fiber, allowing the hollow fiber to pass through an air gap with a length of 0 to 20 cm in 0 to 10 s after the hollow fiber leaves the spinning head, then soaking the hollow fiber in a water bath with a temperature of 0 to 90 DEG C for consolidation forming so as to prepare a polyethersulfone hollow fiber film, fully extracting the polyethersulfone hollow fiber film in hot water with a temperature of 20 to 90 DEG C and carrying out drying. The pressureless polyethersulfone hollow fiber film with the highly-asymmetric spongy structure has far better permeation flux and interception capability compared with common polyethersulfone hollow fiber films; and the preparation method for the film is simple, economic and environment-friendly, is easy to operate and has high production efficiency.

Description

technical field [0001] The invention belongs to the technical field of membrane separation, and in particular relates to a pressureless polyethersulfone hollow fiber membrane with a highly asymmetric sponge structure, which is suitable for the recycling of advanced sewage treatment and the advanced purification of water supply. Background technique [0002] Polyethersulfone (PES) is a high-temperature-resistant polymer material with excellent comprehensive properties. It has a glass transition temperature of 225 ° C, and its theoretical use temperature can reach 98 ° C. It has excellent chemical corrosion resistance and good blood compatibility. , commonly used as microfiltration membrane material. Microfiltration membrane is a kind of separation membrane with pore size screening or size cutoff as the separation mechanism. Its effective pore size range is generally 0.1μm-10μm, and it is mainly used to remove particles from liquid or gas in dead-end filtration mode, such as s...

AI Technical Summary

Problems solved by technology

For example, Chinese patent 200510031066.8 discloses a method for preparing a large-pore polyethersulfone microfiltration membrane. The micropores of the prepared polyethersulfone filter membrane have an asymmetric structure, and the cut-off pore size is 0.1 μm-0.35 μm, but the cross-sectional structure of the flat membrane contains Finger-like macroporous structure, once the separation layer of this structure is damaged, the membrane will be scrapped, and the life of the membrane is very short

Chinese patent 02152963.9 discloses a method for preparing high-flux polyethersulfone microfiltration membranes using inorganic additives. The pure water flux of the prepared polyethersulfone membranes is 230L / (m 2 h), but there are many steps, and the use of dilute acid for post-treatment may have adverse effects on membrane performance and quality

Chinese patent CN102580558A discloses a pressureless polysulfone and polyethersulfone hollow fiber blend membrane, but the microstructure of the membrane is not clear, and the long-term filtration effect cannot be guaranteed

U.S. Patents US4629563 and US4774039 disclose the preparation of asymmetric flat membranes without finger-like macroporous structures, but the use of unstable casting liquid systems does not have the possibility of industrial production

U.S. Patent No. 5,869,174 uses an improved stable casting liquid system to prepare a flat polyethersulfone microfiltration membrane with an asymmetric structure, but the membrane needs to be exposed to air for a long time during the scraping process, and the temperature and humidity of the air are not controlled. In the actual production process, the process conditions are unstable, which is not conducive to the stability of the structure and performance of the flat microfiltration membrane

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