Functionalization of membrane surface by layer-by-layer self-assembly method for dyes removal

Membrane separation processes are an efficient method to manage the amount of wastewater improperly discharged into water due the use of dyes in industrial processes. Thus, polyethersulfone microfiltration membranes were modified with sulfuric acid, titanium dioxide (TiO2) and graphene oxide (GO) solutions by layer-by-layer self-assembly method via electrostatic interaction through a pressure-assisted filtration system. The characterization indicated that the proposed modification was successfully accomplished. The effect of TiO2 and GO masses deposited on the membrane surface was studied. MFTD1.0+GO2.5 membrane showed the best performance among synthesized series achieving a red bordeaux (BR) dye removal of 93.35 % and a flux recovery ratio of >80 %. The treatment of dyes twilight yellow (TY) and safranin orange (SO) was investigated in this membrane achieving a rejection rate of 69.98 and 100 %, respectively. For dyes with high removal rates (BR and SO), other filtration cycles were performed and good results were accomplished. The proposed modification resulted in an efficient treatment of dyes with different characteristics as well as improvement of selectivity and antifouling properties of the membranes. Their reuse potential represents an additional environmental advantage of this process. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.