Fabrication of Graphene oxide membrane with multiple "Plug-ins" for efficient dye nanofiltration.

By the combination of graphene oxide with multiple "plug-ins", the composite membranes are fabricated for nanofiltration with high water permeance (82 L m−2h−1 bar−1) and ideal rejection rate (99.98%). [Display omitted] • The GO membranes contain the multiple "plug-ins" of β-CD and TMC. • The composite membranes exhibit high water permeance and ideal dye rejections. • The different effects of "plug-ins" on the nanofiltration performance are studied. The membranes based on graphene oxide (GO) have shown vast perspectives in nanofiltration, while the swelling of GO membranes in water environment poses a critical challenge for practical applications. In this study, we report the simple fabrication of stable GO membranes in water environment through intercalating multiple "plug-ins": the filter of β-cyclodextrin (β-CD) and the crosslinker of trimesoyl chloride (TMC), which can significantly enhance sieving effect and stability of membranes, and efficiently remove dyes and salts. The β-CD possess the cavity range of 6.0–6.5 Å which is larger than the diameter of water molecules, which can introduce extra water passage and hinder the permeation of dye molecules. In addition, the remaining hydroxyl groups on the membrane surface enhance the hydrophilicity, benefiting to enhance water permeance. At the same time, TMC cross-links β-CD and GO nanosheets to reinforce the membrane. The water permeance of the GO/β-CD/TMC membrane reaches 82 L m−2h−1 bar−1, and the dye rejection (crystal violet) is 99.98%. Therefore, GO membranes prepared by the multiple "plug-ins" incorporation strategy are promising candidates for the nanofiltration process to remove dyes. [ABSTRACT FROM AUTHOR]