Designing poly(vinylidene fluoride) membranes with narrow pore size distribution for microplastics removal from water

Abstract

AbstractMicroplastics have been recognized as a critical threat to the aquatic ecosystem. Membrane separation technology displays great potential to address this issue, while current commonly‐used polymeric microfiltration membranes fall short of high separation efficiency due to their wide pore distribution. A perfectly simple strategy for homoporous membranes fabrication using commercial poly(vinylidene fluoride) (PVDF) was reported in this work, enabling precise removal of microplastics. In this strategy, hydrophilicity of dope solution was enhanced by adding proper amphiphilic surfactants initially, followed by a novelly‐inserted air exposure progress to gently provide water vapor. Both of the two easy steps induced a surface microscopic phase separation to achieve the growth of homopores. Furthermore, the as‐prepared PVDF membrane displayed high surface porosity and bi‐continuous cross‐section structure. As expected, a high rejection (over 97%) towards 500 nm polystyrene microparticles could be achieved along with satisfying water flux of 662 L m−2 h−1 bar−1, which was superior to most current membranes. This work provides not only a new and facile strategy for preparing homoporous membranes employing commercial polymers rather than rarely‐obtained block polymers, but a promising alternative for the efficient separation of aquatic microplastics.