Fabrication, characterization and application of flat sheet PAN/CNC nanocomposite nanofiber pressure-retarded osmosis (PRO) membrane

The aim of this work is to fabricate nanocellulose based nanofiber pressure-retarded osmosis (PRO) via electrospinning technique. PRO process requires high performance, high flux, high rejection and resistant membranes. Conventional phase-inversion membranes are not enough to perform the required water fluxes. Because of this reason, alternative membrane fabrication methods need to be found. Nowadays, electrospinning is the best alternative method to fabricate strong enough nanofiber PRO membranes resistant process operation pressure while providing high flux and high rejection rates. In this study, cellulose nanocrystals (CNC) added polyacrylonitrile (PAN) nanofiber pressure retarded membranes successfully fabricated via tailor-made flat sheet fabrication equipment. According to the scanning electron microscopy, Fourier-transform infrared spectroscopy and dynamic mechanical analysis, parameter and contact angle analysis results, it is concluded that PAN and CNC provided a complete mixture and the addition of CNC increased the mechanical strength in the PAN membranes which is the crucial phenomena in PRO applications. The newly developed membrane can achieve a higher PRO water flux of 300 LMH, using a 1 M NaCl draw solution and deionized water feed solution. The corresponding salt flux is only 1.5 gMH. The reverse flux selectivity represented by the ratio of water flux to reverse salt flux (J(w)/J(s)) was able to be kept as high as 200 L/g for PRO operation. To the best of our knowledge, the performance of the current work developed membrane is superior to all PRO membranes previously reported in the literature.