Forward osmosis (FO) is a very promising technology for desalination due to its noteworthy energy efficiency. However, the lack of effective draw solutes and highly efficient membranes impede FO industrialization. In FO membrane fabrication, thin film composites (TFC) with asymmetric structures have been commonly used as the support layer can significantly enhance the mechanical stability of the membrane. On the support, formation of an extremely thin selectively polyamide layer can be formed resulting in TFC FO membranes with high water flux and reverse salt selectivity. To further enhance the FO performance of TFC membranes, this study examines the feasibility of poly(vinyl alcohol) (PVA) as a support layer prepared via electrospinning. Meanwhile, the selective polyamide layer was formed on PVA through interfacial polymerization. To further enhance the mechanical stability and hydrophilicity of PVA, hydrophilic fillers such as sulfonated graphene oxide (sGO) was used. The sGO filler has high specific surface area and is rich with oxygenous and sulfonate groups which can contribute to the enhancement of water permeability and mechanical stability of the TFC membrane. The sGO was initially dispersed via sonication in the PVA dope solution prior electrospinning.
Initial results reveal enhanced hydrophilicity of PVA support in the presence of sGO (i.e. sGO/PVA) as indicated by its lower contact angle relative to the pure PVA support layer (control). Furthermore, tensile strength and Youngâs modulus of sGO/PVA support were improved in comparison with the control sample. The successful polymerization of thin polyamide layer at the surface of sGO/PVA was confirmed through Scanning Electron Microscopy (SEM-EDS) and Fourier Transform Infrared spectroscopy (FTIR) analyses. Meanwhile, membrane performance of sGO/PVATFC FO membrane is currently being explored.
This research was supported by the National Research Foundation of Korea (NRF) under the Ministry of Science and ICT(2016R1A2B1009221) and Ministry of Education (No. 22A20130012051(BK21Plus)).