An innovative strategy for improving the performance of forward osmosis membrane: stripe-like Turing structure constructed by introducing hydrophilic polyvinylpyrrolidone

Abstract

Improving the performance of forward osmosis (FO) membranes has always been moving forward. Here we fabricate the novel Turing structures in the active layer (AL) of thin film composite (TFC) membrane through effectively introducing the polyvinylpyrrolidone (PVP) macromolecule with hydrophilicity both in the support layer (SL) and AL. The addition of PVP facilitates the formation of sponge-like pores in the SL and stripe-like Turing structures in the AL. The influence of PVP on the morphology and performance of the membranes was investigated by SEM, AFM, XPS, NMR, FTIR. Compared with the water flux (Jw) of the original composite membrane (approximately 25 L m−2 h−1), TFC-PVP (3:1) membrane with Turing structure achieved better performance (approximately 75 L m−2 h−1), and the reverse solute flux/water flux (Js/Jw) value was as low as 0.02 g/L. This study demonstrated that the Turing structures have a favorable effect on the performance of FO membrane and a promisingly practical application in water treatment.