In this study, polyethersulfone (PES)-based membrane was fabricated with metal/covalent-organic frameworks and used for elimination of different organic dyes. According to matrix suggested by Central Composite Design, twenty PES-membranes were synthesized with different mass percentage of polyvinylpyrrolidone (PVP) and metal-organic framework (MOF) at different time of mixing. All membranes were synthesized by phase inversion method and their ability to reject methyl violet 2B was tested at 25.0 °C. The membrane (M2) containing 16% PES, 2% PVP and 0.3 w/w% MOF with mixing time of 3 h was the most economic membrane with the rejection percent of 74.94%. Thus, this membrane was chosen for further modification. Accordingly, a thin layer of covalent-organic framework was formed on the surface of membrane and methyl violet 2B rejection reached to 100% by this membrane (M3). To make comparison, membranes containing only PES and mixture of PES and PVP (M1) were fabricated and FT-IR, XRD and cross-sectional FESEM were used to characterize the PES, M1, M2 and M3 membranes. Finally, experiments were carried out for the determination of pure water flux and rejection percentage (Re%) of cationic and anionic dyes. The results showed that flux and Re% dramatically increased in the case of M2 and M3 compared to PES and M1.
