Membrane surface functionalization by the deposition of polyvinyl alcohol and graphene oxide for dyes removal and treatment of a simulated wastewater

The wide use of dyes has been arousing global concern due to the amount of wastewater improperly discharged into water resources, damaging the environment and human health. In this study, microfiltration polyethersulfone membranes were modified with polyvinyl alcohol (PVA) and graphene oxide (GO) by layer-by-layer self-assembly method and subsequently used for sunset yellow (SY) dye removal. Different masses of PVA (0, 30 and 60 g) and GO (0.5, 1 and 1.5 g) were deposited on the membrane surface, in which the MF/PVA(60)+GO(1)+PVA(30) achieved the best performance among all modifications, with removal greater than 99.90%, similar to 80% flux recovery rate and good regeneration ability (>94% removal after 5 reuse cycles). Moreover, BSA filtration confirmed its antifouling properties. In order to simulate a real wastewater, the SY dye filtration in the presence of dissolved salts was investigated, wherein a satisfactory removal rate (86.17%) was found for MF/PVA(60)+GO(1)+PVA(30). Filtration tests were also performed with tartrazine yellow and amaranth dyes, which removal outcomes (>99%) confirm the versatility and efficiency of this membrane. The characterization by physical-chemical and spectroscopic techniques indicated that the membrane was successfully modified. Therefore, the proposed modification demonstrated a significant improvement in dyes removal, which allows its application for wastewater treatment purposes.