Preparation method of hollow fiber nanofiltration membrane

Abstract

The invention discloses a preparation method of a hollow fiber nanofiltration membrane, and provides the preparation method of the hollow fiber nanofiltration membrane continuous in technical process, uniform in nanofiltration functional layer and few in deficiencies. The method comprises the following steps of: using polyelectrolyte aqueous alkali as an outer coagulating bath and a mixed liquor of water and a solvent for the coagulating bath as an inner coagulating bath, spinning and forming a hollow fiber nanofiltration membrane spinning and membrane forming system through a hollow spinning nozzle and a double diffusion process, and initially curing and forming a hollow fiber membrane; and adding the initially cured hollow fiber nanofiltration membrane into an aqueous liquor of polyamine, erasing the suspended liquid on the surface, adding the membrane into an organic liquor of polyacyl chloride, and drying and curing the membrane to obtain the hollow fiber nanofiltration membrane. The method provided by the invention is continuous in technical process, uniform and controllable in nanofiltration functional layer and few in defects, and has a wide prospect in the fields of seawater and brackish water desalination, treatment and recovery of sewage and wastewater, preparation of ultrapure water and the like.

Description

technical field [0001] The invention relates to the technical field of membrane separation, in particular to a preparation method of a hollow fiber nanofiltration membrane. Background technique [0002] Membrane separation technology is widely used in material separation, purification and concentration processes. It can be operated continuously at room temperature without phase change; it has the advantages of energy saving and environmental protection in large-scale production. Nanofiltration membrane is a pressure-driven separation membrane between reverse osmosis and ultrafiltration. In application, nanofiltration membrane has two remarkable features: first, its molecular weight cut-off is between reverse osmosis membrane and ultrafiltration membrane, about 200-2000, and can intercept low molecular weight organic substances such as sugar; The functional surface layer of the nanofiltration membrane is composed of polyelectrolyte, which makes it have different rejection ra...

AI Technical Summary

Problems solved by technology

In the prior art, the ultrafiltration membrane that has been completely cured and formed is mostly immersed in the aqueous solution of polyamine, and then fully dried after taking it out. For the hollow fiber membrane, it is difficult to effectively maintain the aqueous solution of polyamine in the membrane due to the existence of the cylindrical surface. Sufficient and uniform distribution on the surface, so that the effective components of polyamines are difficult to distribute evenly on the surface of the dried membrane filaments, so in the subsequent process of impregnating the organic solution of polyacyl chlorides, it will cause defects in the functional layer obtained by interfacial polymerization

In addition, the full drying process in the middle also leads to a long preparation cycle of nanofiltration membranes, which is not conducive to continuous industrial production