Water decolorization and antifouling melioration of a novel PEBA1657/PES TFC membrane using chitosan-decorated graphene oxide fillers

Abstract

Novel chitosan-tailored graphene oxide (CSGO)-embedded poly(ether-b-amide) (PEBA) thin film nanocomposite (TFN) membranes have been fabricated and coated on ultraporous polyethersulfone. To synthesize the nature-friendly CSGOs, the covalent functionalization of GO has been done by carbohydrate polymer chitosan. The green nanofillers were then incorporated in the PEBA selective layer at different loadings up to 2 wt%. The structural studies were performed using FTIR, XRD, SEM, AFM and contact angle analyses, which confirmed the appropriate filler dispersion and enhanced hydrophilicity of the TFN membranes. Moreover, using nanofiltration (NF) for malachite green (MG) dye rejection, the effects of CSGO loadings, transmembrane pressure, feed concentration and duration on the membranes separation performance were also assessed. The membrane loaded with 0.1 wt% of CSGO showed the highest permeate flux, 3.2 times higher than that of the TFC membrane. The surface-decorated CSGO-filled TFN membranes also represented improved antifouling performance because the CSGO nanofillers had a positive charge due to the protonation of chitosan N-H groups in the acidic medium of this work.