Thin film composite membranes combining carbon nanotube intermediate layer and microfiltration support for high nanofiltration performances

In this work, we report a novel thin film composite (TFC) nanofiltration membrane (NFM) by incorporating a thin hydrophilic multi-walled carbon nanotubes (MWCNTs) interlayer between the microfiltration membrane support and the dense skin layer from interfacial polymerization. The MWCNT interlayer can absorb and storage the aqueous amino solution to facilitate the following interfacial polymerization, as well as provide a robust mechanical support to enable the nanofiltration of thin skin layer on the microporous substrate. Compared to those TFC NFMs supported by the ultrafiltration membranes, our membranes exhibit increased water permeation flux as high as 105.4   L   m −2   h −1 at 0.6   MPa (which doubles the flux of the conventional ones) with high rejection for Na 2 SO 4 (~95%). Moreover, the TFC NFMs show good stability during a long-term nanofiltration operation. This research provides us a promising approach to fabricate the high-flux NFMs for low pressure operation.