Effects of Co-Solvent on the Morphology, Physicochemical Properties, and Performance of PVDF Electrospun Membranes in Comparison to Flat-Sheet Membranes

Abstract

Poly(vinylidene fluoride) (PVDF) membranes were fabricated using two different methods: the electro-spinning technique and the phase inversion process. The effect of a DMF/acetone solvent composition on the quality of the electrospun fibers of the PVDF membrane was investigated. The prepared PVDF membranes have been characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and contact angle. Uniform fibrous membranes with fiber diameters ranging mainly from 6 μm to 1.5 μm were formed from 16% (w/w) PVDF solutions in 50/50 (w/w) DMF/acetone at 30 kV voltage and 0.3 mL/h flow rate. The effect of surface morphology and hydrophilicity on anti-fouling potential was also studied and compared with flat-sheet membranes. It was found that the spun fibrous membranes exhibited the best hydrophilicity and antifouling properties with an average pure water permeability up to 400 L/m2/h, higher than that of the flat-sheet membranes, which exhibited 200 L/m2/h. Performance evaluation of the prepared PVDF membranes (water flux and organic matter retention) has been done through the use of a dead-end apparatus, where the results demonstrated the efficiency of electrospun membrane over the conventionally prepared flat-sheet membrane for utilization as a pretreatment stage of ultrafiltration and microfiltration (MF/UF), before reverse osmosis (RO) in the desalination plant.