Large-flux enhanced PVDF unlined ultrafiltration membrane and preparation method thereof

Abstract

The invention relates to a large-flux enhanced PVDF unlined ultrafiltration membrane. The ultrafiltration membrane is prepared from, by weight, 22-30 parts of dopamine-modified polyvinylidene fluoride, 10-20 parts of a hydrophilic agent, 50-70 parts of a polar solvent, 10-20 parts of a pore forming agent and 5-10 parts of an auxiliary agent; the hydrophilic agent contains triethanolamine. According to the large-flux enhanced PVDF unlined ultrafiltration membrane, by blending and modifying the hydrophilic agent, the auxiliary agent and the dopamine-modified polyvinylidene fluoride in the polarsolvent, the surface tension of the surface of the membrane and the inner walls of membrane pores is reduced, and the hydrophilicity of the polyvinylidene fluoride is improved; the triethanolamine inthe hydrophilic agent has hydrogen-bond interaction with polar bonds in the auxiliary agent and polar bonds in a dopamine composite layer, the hydrophilicity can be maintained for a long time accordingly, the antifouling property of the membrane is improved, and the high operating flux is kept for a long time; the small-molecule pore forming agent does not easily block the pores, the membrane forming performance is good, the pure water flux is good, the degree of entanglement with a main material is low, and the pore forming agent is easily detached from the surface of the membrane; the auxiliary agent effectively improves the melt processability, and the mechanical properties are greatly improved.

Description

technical field [0001] The invention relates to the technical field of ultrafiltration membranes, in particular to a large flux enhanced PVDF ultrafiltration membrane without lining and a preparation method thereof. Background technique [0002] Ultrafiltration is a membrane separation process that takes pressure difference as the driving force and uses the sieving mechanism to intercept macromolecular solutes and separate them from solvents or small molecular solutes according to the size of the substance. The effective pore size of the ultrafiltration membrane used is between 2 ~100nm. Utilizing the screening effect of the micropores on the surface of the ultrafiltration membrane, the separation and purification of substances with different molecular weights can be realized, and it has a good effect on the removal of particles, colloids, bacteria and various organic substances. In recent years, it has been widely used in water treatment, food, Electronics, machinery, chem...

AI Technical Summary

Problems solved by technology

The PVDF membrane in the prior art has poor hydrophilicity, is easy to absorb pollutants during use, and has defects such as lower treatment efficiency, which needs further improvement