Developing ultra-high gas permeance PVDF hollow fibers for air filtration applications

Abstract

Abstract To minimize the growing concerns of adverse air pollution, many efforts have been devoted to develop filters to filtrate airborne particles. However, the development of a filter with high filtration efficiency and low air resistance is challenging. In this study, we have successfully developed polyvinylidene fluoride (PVDF) hollow fibers with an ultra-high gas permeance for air filtration applications. By using dilute PVDF dopes with SiO2 additives and applying KOH etching processes, the N2 permeance of resultant hollow fibers increases significantly. The optimized PVDF6.5/SiO2-0.25 hollow fiber, made from 6.5% PVDF dopes containing 25 wt% of SiO2 to PVDF, displays a N2 permeance of 8.1 × 105 GPU after the KOH treatment. Moreover, the KOH treated PVDF6.5/SiO2-0.25 hollow fiber shows filtration efficiency of 99.9999% against both sodium chloride (NaCl) particles and bis(2-ethylhexyl) sebacate (DEHS) particles. Importantly, the filtration efficiency remains at 99.9999% over continuous 36-h filtration experiments under a highly polluted situation with a very small increment in a pressure drop of 100 Pa. Therefore, the proposed methods allow us to fabricate hollow fibers with an ultra-high gas permeance and excellent air filtration performance. The newly designed PVDF hollow fiber may have great potential to be a filter media for air filtration applications.