Altering substrate properties of thin film nanocomposite membrane by Al₂O₃ nanoparticles for engineered osmosis process

The scarcity of energy and water resources is a major challenge for humanity in the twenty-first century. Engineered osmosis (EO) technologies are extensively researched as a means of producing sustainable water and energy. This study focuses on the modification of substrate properties of thin film nanocomposite (TFN) membrane using aluminium oxide (Al₂O₃) nanoparticles and further evaluates the performance of resultant membranes for EO process. Different Al₂O₃ loading ranging from zero to 0.10 wt% was incorporated into the substrate and the results showed that the hydrophilicity of substrate was increased with contact angle reduced from 74.81° to 66.17° upon the Al₂O₃ incorporation. Furthermore, the addition of Al₂O₃ resulted in the formation of larger porous structure on the bottom part of substrate which reduced water transport resistance. Using the substrate modified by 0.02 wt% Al₂O₃, we could produce the TFN membrane that exhibited the highest water permeability (1.32 L/m².h.bar, DI water as a feed solution at 15 bar), decent salt rejection (96.89%), low structural parameter (532.44 μm) and relatively good pressure withstandability (>25 bar).