Polyvinyl chloride/quaternized poly phenylene oxide substrates supported thin-film composite membranes: Enhancement of forward osmosis performance

Abstract

Abstract Quaternized poly phenylene oxide (QPPO) was synthesised and used as a modifier material to blend with polyvinyl chloride (PVC) to cast the substrate for thin-film composite (TFC) forward osmosis (FO) membranes. The addition of QPPO improved the porosity, hydrophilicity, and morphology of the substrate, thereby weakening the internal concentration polarisation of TFC membranes. Furthermore, the introduction of QPPO improved the structure of the active layer, which led to higher water permeability. Moreover, the mechanical properties of the TFC membranes were significantly improved after the introduction of QPPO. As a result, introducing QPPO significantly increased the FO performance. In addition, the TFC membrane based on a 40% QPPO blend ratio exhibited optimal FO performance: a high water flux of 71.21\xa0L\xa0h−1\xa0m−2 and an extremely low specific reverse solute flux of 0.079\xa0g\xa0L−1 under the active layer facing the draw solution (DS) mode by utilising 1\xa0M NaCl as the DS and deionised (DI) water as the feed solution; this FO performance remained fairly stable during long-term operation. This study suggests that introducing QPPO into the substrate is a sensible strategy for fabricating high-performance TFC FO membranes.