Formation and characterization of polyamide composite electrospun nanofibrous membranes for salt separation

Currently, electrospun nanofibrous membranes (ENMs) are classified in the microfiltration range. In this study, we explored the applicability of using ENMs for nanofiltration (NF) applications through a surface modification approach. A polyamide layer was formed on the surface of the ENMs through interfacial polymerization with two different approaches. In the first approach (approach A), ENMs were soaked in an aqueous phase followed by an organic phase; in the second approach (approach B), we reversed this sequence. This resulted in different surface morphologies over the ENM surface. The best approach B allowed the separation of 80.7% of 2000‐ppm MgSO 4 and 67.0% of 2000‐ppm NaCl at a pressure of 70 psig under a dead‐end filtration setup. The fluxes attained were 0.51 and 0.52 L m −2 h −1 , respectively. In addition, the effect of the pore size on the formation of a polyamide film was investigated. It was realized that bubble points of 1.8 and 3.4 μm were both able to support the polymer film on its surface, but their separation efficiency differed slightly. These findings suggest that ENMs could be used beyond their current microfiltration stage, and hence, their use could be widened to NF membranes.