A 15-year review of novel monomers for thin-film composite membrane fabrication for water applications

Concerted effort has been made over the years to develop advanced polyamide (PA) thin-film composite (TFC) membranes with improved surface properties for water applications. In this chapter we perform a comprehensive review on the novel monomers that were used in the last 15 years to develop a PA layer of TFC membranes for nanofiltration, reverse osmosis, and forward osmosis processes. It provides insight for researchers into fabricating improved properties of TFC membranes through utilization of novel monomers that can be added into either aqueous solution or organic solution during the interfacial polymerization process. Depending on the characteristics of monomers, a new TFC membrane with improved performance in terms of water flux, rejection, fouling resistance, and chlorine tolerance could be produced that outperformed the control membrane made of commonly used monomers in the laboratory. Nevertheless, our analysis indicated that some of the novel TFC membranes (particularly for reverse osmosis applications) did not show significantly better water permeability and rejection than the commercial TFC membranes. Therefore there is still room for improvement for this research topic. Furthermore, the long-term stability of these novel membranes has not been demonstrated by researchers, and it is also unclear whether these novel membranes can compete with the commercial TFC membranes in terms of manufacturing costs, as some novel monomers are expensive.