posted on 2021-10-29, 14:04authored byXing Wu, Thomas M. Kohl, John Tsanaktsidis, Zongli Xie
Thin-film composite
(TFC) membranes have been widely used in forward
osmosis for desalination and water treatment. Nonetheless, the dilemma
between selectivity and permeability and serious internal concentration
polarization (ICP) still limits the filtration efficiency of TFC-FO
membranes. Herein, a high-efficiency TFC-FO membrane was synthesized
by embedding a polysulfone (PSf)/polyaniline (PANI) coblend membrane
as the substrate. Impacts of PANI on both the substrate and the TFC-FO
membrane were investigated by optimizing the concentration of PANI
in substrates. The results indicated that the addition of PANI can
adjust the properties of substrates, producing substrates with better
hydrophilicity and improved porosity. This further mitigated the interfacial
polymerization process and reduced the polyamide layer thickness.
Compared to the pristine PSf-based TFC-FO membrane and the commercial
FO membrane, the PSf/PANI-based TFC-FO membrane with 0.6 wt% PANI
loading exhibited significantly enhanced water flux (209%) and decreased
specific salt flux (40%). Moreover, the addition of PANI into substrates
effectively mitigated the ICP phenomenon of the PSf/PANI-based TFC-FO
membrane, with a 290% lower structure parameter (S) than that of the pristine TFC-FO membrane. This work offers an
effective strategy to enhance the filtration capabilities of TFC-FO
membranes by tuning substrate properties.