Synthesis of robust flexible polyethersulfone ultrafiltration membranes supported on non-woven fabrics for separation of NOM from water

Abstract

This work describes the synthesis of structurally robust ultrafiltration (UF) polyethersulfone (PES) membranes supported on three different types of non-woven fabrics (NWFs) prepared using a simple phase inversion method. The NWF supported membranes exhibited high mechanical strength compared to the unsupported PES membranes modified with polyvinyl pyrrolidone (PVP) due to the strength provided by the NWFs. The tensile strength of the supported PVP modified membranes was ~7 MPa compared to ~2 MPa observed for the PVP modified unsupported UF membranes. The use of the NWFs clearly provides robustness to the modified membranes. The membrane surfaces became hydrophilic with addition of PVP and the pore sizes increased with an increase in PVP concentration (scanning electron microscopy (SEM) results). The rejection of humic acid (as a model NOM compound) was 98% for PES on NWF1, while PES membranes supported on NWF2 and NWF3 gave rejections of 94% and 96%, respectively; all with good fouling resistance. This work demonstrates that the use of a NWF support allows for the modification of the surface of the membranes without compromising the overall strength of the membranes, but more importantly the ability of the membranes to reject HA while exhibiting high resistance to fouling.