NH2-Fe3O4-regulated graphene oxide membranes with well-defined laminar nanochannels for desalination of dye solutions

Graphene oxide (GO)-based nanofiltration membranes, featuring well-ordered microscopic structure, well-defined 2D nanochannels and superior molecular sieving ability, have attracted sustained research interest in molecular and ionic separation. However, most of current GO laminar membrane have a poor water flux and high rejection of both dyes and salts, which is not suitable for the dye/salt mixture separation. Herein, we report a vacuum filtration strategy to fabricate GO/NH 2 -Fe 3 O 4 nanofiltration membranes with high water flux and excellent separation performance for dye/salts mixture by introducing NH 2 -Fe 3 O 4 . The NH 2 -Fe 3 O 4 is not only worked as the rigid spherical nanospacer to tune GO interlayer spacing but also as crosslinkers to improve the stability of GO membrane in water. FTIR, XRD , SEM , zeta potential and contact angle were applied to analyze the chemical composition and morphology of as-prepared membranes. The effect of intercalated NH 2 -Fe 3 O 4 nanoparticles on overall performance of the GO/NH 2 -Fe 3 O 4 membranes was systematically investigated. The resulted membrane with 8 wt% of NH 2 -Fe 3 O 4 loading has high water flux of up to 78 Lm − 2  h − 1 , which is 4.8 times higher than that of pure GO membrane. Moreover, such membrane also displays high congo red rejection (94%) and low NaCl rejection (~15%), rendering the membranes promising for dye/salt mixtures separation.