Construction of robust one-dimensional nanowire-regulated graphene oxide membranes for efficient dye/salt separation

Abstract

Loose nanofiltration (NF) for graphene oxide (GO) membranes is an emerging efficient strategy for separating dye/salt mixtures in textile wastewater to realize sustainable resource recovery. This study proposes a novel approach for constructing a laminated GO membrane with interlayer water-transporting nanochannels by intercalating tannic acid nanowires (TANs). The interlayer spacing of the GO membrane can be expanded by one-dimensional TANs while cross-linking between hydrophilic TANs and GO nanosheets enhance the mechanical stability of this sheet-wire structure and interlayer channels. The membrane is able to achieve excellent water permeability without sacrificing selectivity due to the dual driving force resulting from the ultrafast water transport ability of primitive graphene planes and interlayer hydrophilic nanowires. The modified GO membrane exhibits a high water permeability of 52.1 L m−2 h−1 bar−1, which is twice that of the pure GO membrane and excellent selectivity of 85.5 to the methyl blue/NaCl mixed solution. Overall, this work provides a feasible strategy for constructing a mixed-dimensional GO-based membrane with a robust structure and multi-pathways to achieve excellent perm-selectivity for dye/salt separation.