Application of flying jet plasma for amelioration of polyvinylidene fluoride membrane properties towards enhanced membrane distillation

Abstract

AbstractThis study explored the feasibility of applying sequential argon‐CF4 plasmas treatment as a featured approach towards enhancement of polyvinylidene fluoride (PVDF) membrane structure and surface topography for application in membrane distillation (MD). Systematic procedures were conducted to synthesize membranes of different combinations composed mainly from PVDF and assisted by addition of polyvinylpyrrolidone (PVP) at different percentages. Upon casting four classes of the membranes, the analysis results via Scanning Electron Microscopy (SEM), Energy Dispersive X‐Ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), as well as the contact angle measurements have shown that the membrane surface topography was mediated in terms of appearance of clear bumps on the surface. Upon implementing the sequential treatment cycles for several durations, the surface topography has considerably changed at the end of argon treatment cycle in terms of appearance of pores at small size. Further changes on the surface topography were detected at the end of CF4 treatment cycle elucidated by increase in the pore size and uniform distribution of the pores along the examined membranes. The function of the sequential plasma treatment was become certain upon implementing MD experiments for dilute solution of ethanol/water, in which higher permeation water flux and permeate separation index were observed for membranes of higher PVP content and sequentially treated for 6 min.