Effects of Polysulfone (PSf) Support Layer on the Performance of Thin-Film Composite (TFC) Membranes

The performance of thin-film composite (TFC) membranes was related to the properties of support layers. In this study, polysulfone (PSf) membranes formed by the phase inversion process under various concentrations of PSf and polyvinylpyrrolidone (PVP) additive were used as support layers to prepare polyamide (PA) TFC membranes by the interfacial polymerization (IP). The effects of PSf and PVP concentrations on the properties of support layer such as equilibrium water content (EWC), pure water flux, and molecular weight cut off (MWCO) were investigated. And the performance of resulting TFC membranes was evaluated in terms of water flux and salt rejection. The pure water flux decreased with increasing PSf concentration in support layers. The decrease of water flux could be attributed to a lower effective area of PA when a denser support layer was used. The addition of PVP in the casting solution resulted in a more porous and hydrophilic support layer. However, the water flux of TFC membranes decreased which could be due to the larger effective thickness of PA.