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

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 (PS0.5-TFN0.05 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 PS0.5-TFN0.05 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.