High performance polyamide crosslinked graphene oxide/MPNs nanofiltration membrane for wastewater purification

Nanofiltration membranes prepared via polyamide crosslinked Graphene oxide (GO) sheets have been considered to be promisingly applied in water purification. Unfortunately, the water flux of polyamide crosslinked GO-based membranes is strongly restricted due to the small interlamellar spacing of GO sheets. To solve this problem, the microporous polymer networks (MPNs) and GO sheets were introduced into the polyamide layer to reach a synergistic effect in this work. Specifically, the interlamellar interaction of GO sheets was manipulated via intercalating MPNs nanoparticles. The   synergistic   effect   of   GO   and   MPNs   was   significantly   beneficial   for the improvement   of   water   flux. A delicate wrinkled membrane surface was formed via regulating the content of MPNs nanoparticles, which could provide larger area in contact with water molecules, further improved the water flux. The prepared membrane with 1 g/m 2 MPNs and 41.8 mg/m 2 GO sheets gave an evidently increased water flux from 6.6 L m −2 h −1  bar −1 to 25.1 L m −2 h −1  bar −1 compared with the GO-based membrane without MPNs. Additionally, a high Na 2 SO 4 retention of 94% and considerable efficiency in anti-fouling property were also observed for the prepared membranes.