Desalination through membranes is a potential alternative for water treatment, but fouling is still a challenge, causing low fluxes. Aiming to improve the water flux through thin film composite polyamide/polysulfone membranes, TFC PA/PSf, the use of graphene oxide, GO, both in the polysulfone support and polyamide top layer is investigated in this work. The GO-added membrane showed a decrease in water contact angle (from 76 to 25°) and zeta potential and an increase in water permeability of ip to up 2.3 L m−2 h−1 bar−1. The polyamide skin layer was identified by FTIR and SEM images. Nanofiltration tests showed low rejection of the membranes to NaCl (32%), due to defects in the PA layer, with a flux of 12 L m−2 h−1. Regarding Na2SO4, the rejection coefficient was increased to 91%, with flux of 9.4 L m−2 h−1. The investigation of such membranes in forward osmosis also showed a potential application of GO-containing membranes. Graphene oxide can improve permeation through PA/PSf membranes. For the performance in liquid media, the high rejection shown in nanofiltration tests for Na2SO4 indicated that membranes can be used in the removal of salts with higher density charges than NaCl. It was possible to modulate membrane performance upon changing operational conditions.
Silva et al. (Mon,) studied this question.