Preparation of thin film composite membrane with emphasis on structure improvement of substrate via water as a strong non-solvent additive

The effect of polysulfone (PSf) substrate with different morphology and porosity on the properties of polyamide (PA) thin film which formed via identical interfacial polymerization (IP) conditions was investigated. Accordingly, bulk modification of PSf substrate was manipulated through adding water as non-solvent additive (NSA) to the polymer solution casting at different concentration (0-4 wt.%). The performance of developed thin film composite (TFC) membranes was evaluated in brackish water desalination. Results were combined with morphology, wettability and polymer viscosity studies. The findings showed that addition of small amount of water in the casting solution resulted in more porous and similar hydrophobic substrate. Interestingly, only slight changes on salt rejection was observed on any TFC membranes. Furthermore, highly porous and relatively hydrophobic substrates produced more permeable TFC membrane. Consequently, the best performing TFC membrane produced based on its performance was the membrane prepared over substrate of 2 wt. % water in casting solution.

Keywords:

TFC membrane , non-solvent additive , substrate layer , porosity