Highly permeable and stable forward osmosis (FO) membrane based on the incorporation of Al2O3 nanoparticles into both substrate and polyamide active layer

Abstract

In the present study, hydrophilic Al₂O₃ nanoparticles were used as additives in both substrate and polyamide active (PA) layer to improve forward osmosis (FO) membrane properties. Via incorporation of 0.5 wt% Al₂O₃ into the substrate and 0.05 wt% Al₂O₃ into the PA layer (PS_0.5-TFN_0.05 membrane), the water flux reached 27.6 L m⁻² h⁻¹ with a relatively low solute reverse flux of 7.1 g m⁻² h⁻¹ using DI water as a feed solution and 1 M NaCl as a draw solution. Simultaneously, we found that the incorporation of Al₂O₃ nanoparticles into both the substrate and PA layer resulted in a better enhancement of FO performance and a higher increase in water flux than the simple incorporation of nanoparticles in substrate. Moreover, the PS_0.5-TFN_0.05 membrane remained stable during long-term FO tests and under serious water environment. To the best of our knowledge, this is the first study to report the effect of Al₂O₃ nanoparticles on FO performance, and the results verify the potential use of these nanoparticles in the fabrication of highly permeable FO membranes.