PVDF Electrospun Nanofiber Membranes for Microfiltration: The Effect of Pore Size and Thickness on Membrane Performance

Abstract

Microfiltration membranes are needed in wastewater treatment, water purification and concentration processes. To separatemicroorganisms and suspended particles from process liquid, a contaminated fluid, especially water, is passed through a porousmembrane. Electrospun nanofiber membranes could be used for this aim with their nanoscale fibers, small pore size, low weight andhigh permeability. The main purpose of this study is to show the relationship between the average fiber diameter and thickness of thePVDF nanofiber membrane and the pore size and liquid filtration efficiency. PVDF is a widely used polymer in water treatmentprocesses. It is highly non-reactive thermoplastic fluoropolymer with outstanding physical and chemical properties. In this study, PVDFnanofibers were produced from 12, 14 and 16% (w/v) polymer solutions by electrospinning method to achieve three different meandiameters. 15 min, 30 min, 60 min, 3h and 5h of production periods were used for producing various thicknesses. According to poresize measurements, the differences in mean flow pore size (MFP) of 16PVDF and 14PVDF nanofiber membranes were not distinct.However, due to thin nanofiber diameter (278.58 nm) and high amount of nanofibers, biggest pore size (FBP) of 12PVDF-5h was thesmallest. There was also significant difference between 12PVDF-5h and 12PVDF-3h, and FBP of these two membranes were smallerthan other three 12PVDF nanofiber membranes. Liquid filtration property of produced electrospun PVDF nanofibers were evaluated byturbidity rejection of a kaolin solution. In correlation with the pore size results it was seen that best turbidity rejection percent wasbelonging to 12PVDF-5h and worst was belonging to 16PVDF-15min nanofiber membranes. Nevertheless, all of the producedelectrospun PVDF nanofiber membranes can be effectively used to remove contaminants from wastewater at a relatively low cost.