Exploring the effect of pore size distribution on anti-pollution performance: an in-depth study of hollow fiber ultrafiltration membranes based on PVDF

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A research paper published in the Chinese Journal of Chemical Engineering pointed out that polyvinylidene fluoride (PVDF), as a material with excellent thermal stability, high strength mechanical properties and good processing characteristics, has been widely used in ultrafiltration (UF), microfiltration (MF) and membrane bioreactor (MBR). However, in the actual operation process, membrane pollution is the key bottleneck restricting the performance of PVDF membrane, which will greatly reduce the permeability of the membrane and affect the economic benefit. Although conventional measures to reduce membrane contamination such as mechanical washing, high-pressure backwashing and chemical cleaning can temporarily improve the flux, chemical cleaning requires high corrosion resistance of membrane materials, and frequent use will shorten the service life of the membrane. Although high pressure backwashing and mechanical washing can effectively remove the sediment on the membrane surface, they have limited effect on the deep pore plugging pollution.

PVDF membrane

This study highlights the importance of improving the microstructure of PVDF membranes to improve their anti-pollution properties. The results show that the microstructure characteristics of PVDF membranes, especially the pore size distribution, are closely related to their anti-pollution behavior. However, the internal law of how membrane microstructure affects membrane fouling behavior remains to be clarified.

To this end, the study selected PVDF membrane samples with pore size ranging from 24 to 94 nm, and systematically studied the influence of different pore size distributions on membrane fouling behavior. The experimental results showed that the PVDF membrane with smaller pore size showed stronger anti-fouling ability, and the PVDF membrane with a pore size of only 24 nm was particularly outstanding in anti-fouling performance. As the pore size of the PVDF membrane decreases, the critical flux increases significantly, from 34 to 43 L/m ² · h to 105 to 114 L/m ² · h, which clearly indicates that the PVDF membrane with small pore size has a lower tendency to pollute and a higher anti-pollution efficiency.

In summary, this paper deeply analyzed the relationship between the microstructure of PVDF membrane and the anti-pollution performance, and provided a scientific basis for the development of PVDF ultrafiltration membrane with high anti-pollution performance. It is of extremely important significance for improving the actual operating flux and service life of PVDF ultrafiltration membrane and further promoting the research and development technology level of PVDF membrane.

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