Abstract
Nanofiltration (NF) membranes have been applied to various applications such as pre–treatment of reverse osmosis (RO) membrane processes, separation and concentration of small organic molecules and multivalent ions. Polyamide membranes fabricated by interfacial polymerization are mainly used for NF membranes, because of their high water permeability and controllable separation performance. The improvement of the water permeability of NF membranes is crucial because it directly leads to energy efficiency. In this review, the recent approaches to improve the water permeability of polyamide NF membranes, including our new approach, “post–pore expansion”, are introduced. The “post–pore expansion” using methoxycarbonyl–diamine achieved the high water permeability comparable to nanomaterials-composite NF membranes.
