Effects of Casting Solvents on the Morphologies, Properties, and Performance of Polysulfone Supports and the Resultant Graphene Oxide-Embedded Thin-Film Nanocomposite Nanofiltration Membranes

In this study, the influences of different casting solvents including N-methylpyrrolidinone (NMP), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF) on the morphologies, properties, and performance of polysulfone (PSU) supports and their resultant graphene oxide (GO)-embedded thin-film nanocomposite (TFN) nanofiltration (NF) membranes were systematically investigated. The influences of casting solvents on the mechanism of immersion precipitation phase-inversion process and the morphology of PSU supports were analyzed by Hansen solubility parameters. The results indicated that the physicochemical properties and performance of both PSU supports and the resultant composite NF membranes were significantly affected by the type of casting solvents. PSU support made from NMP exhibited a small surface pore size that prevented the penetration of poly(piperazine amide) (PPA) into the PSU pores, which contributed to form a defect-free active layer with excellent permeaselectivity regardless of TFC or TFN...