High performance thin-film composite (TFC) forward osmosis (FO) membrane fabricated on novel hydrophilic disulfonated poly(arylene ether sulfone) multiblock copolymer/polysulfone substrate

For the first time, thin-film composite (TFC) forward osmosis (FO) membranes are fabricated via interfacial polymerization on polysufone (PSf) substrates containing different contents of disulfonated poly(arylene ether sulfone) hydrophilic-hydrophobic multiblock copolymer (BPSH100-BPS0), with the purpose to increase the substrate hydrophilicity while maintaining the mechanical strength. It is found that the tensile strength of the substrate only decrease slightly (23.3%) upon addition of as high as 25 wt% of BPSH100-BPS0 in the PSf; while the FO performance of the TFC membrane (TFC-25.0) is significantly improved due to the enhanced hydrophilicity and porosity of the substrate. The TFC-25.0 exhibits extremely high pure water flux of 40.5 LMH in the FO mode and 74.4 LMH in the PRO mode when using 2 M NaCl as the draw solution, which are almost one-fold higher than the TFC membrane without addition of BPSH100-BPS0. The potential of using the TFC-25.0 for desalination is also investigated by using a 2 M NaCl draw solution and a model seawater (3.5 wt% NaCl) as the feed. The water fluxes of 18.6 and 29.06 LMH are achieved by the TFC-25.0 under FO mode and PRO mode, respectively. To the best of the authors' knowledge, these values are among the highest in currently reported literature for seawater desalination.