Reinforced fluorinated copolymer and polyurethane electrospun layered nanofiber-based membranes for effective model water dead-end microfiltration

Abstract

The research presented herein describes the preparation of electrospun homogeneous nanofibrous structures with customized morphology and properties, as well as textile support for necessary reinforcement for microfiltration applications. Findings report membranes comprising a polyurethane or fluorinated copolymer nanofibrous layer and polyethylene terephthalate nonwoven textile as support were evaluated. The investigation encompassed various constructions of materials, which include the influence of nanostructure morphology, the process of membrane cleaning by backwashing, and factors affecting flux, filtration efficacy, and working life. Application of membrane support made from polyethylene terephthalate with a large distribution of polymer chain provides a sufficiently strong connection with a layer of nanofibers with minimum penetration into the nanostructure involved in flux improvement. It was discerned that nanostructures with a morphology of six layers from thick (fiber diameter ~ 500 nm) and thin (fiber diameter ~ 180 nm) nanofibers with mean pore size 0.67 μm in comparison with membranes prepared from thin nanofibers only (mean pore size 0.26 μm) exhibited improved flux (17 times higher after 150 min of filtration process). In contrast, the filtration efficacy of both membranes for filtering submicron particles remained stable and highly efficient. It also proved to smooth out the surfaces of the novel membranes, which simplifies the removal of caked-up debris. Cleaning the filter by backwashing renewed the efficacy of the developed membranes for filtration and extended their working life. Finally, repeatedly backwashing the thin nanofiber layer membrane raised the water flux measured as 230 L m−2 h−1, that is, six times higher than without backwashing.