Ultrahigh permeance of a chemical cross-linked graphene oxide nanofiltration membrane enhanced by cation-π interaction.

Ruobing Yi,Liang Chen,Risheng Yu,Junlang Chen,Minghong Wu,Jian Lan,Zhikun Wang,Rujie Yang

doi:10.1039/c9ra07109a

Abstract

Cross-linking with large flexible molecules is a common method to improve the stability and control the interlayer spacing of graphene oxide (GO) membranes, but it still suffers from the limitation of low water flux. Herein, a novel high flux GO membrane was fabricated using a pressure-assisted filtration method, which involved a synergistic chemical cross-linking of divalent magnesium ions and 1,6-hexanediamine (HDA) on a polyethersulfone (PES) support. The membrane cross-linked with magnesium ions and HDA (GOHDA–Mg2+) exhibited a high water flux up to 144 L m−2 h−1 bar−1, about 7 times more than that of cross-linked GO membranes without adding magnesium ions (GOHDA), while keeping excellent rejection performance. The GOHDA–Mg2+ membrane also showed an outstanding stability in water for a long time. The effects of magnesium ions on the GOHDA–Mg2+ membrane were analyzed using several characterization methods, including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The results indicated that magnesium ions not only promoted reasonable cross-linking, but also improved the stacking of GO sheets to give lower mass transfer resistance channels for water transport in the membranes, resulting in the ultrahigh permeance of the GO membranes.

Highlights

Graphene oxide (GO) is a two-dimensional network with a thickness of one atom, which has great potential in the eld of water treatment because of its excellent hydrophilicity,[1] remarkable stacking property[2] and other unique properties.[3]
The membrane cross-linked with magnesium ions and HDA (GOHDA–Mg2+) exhibited a high water flux up to 144 L mÀ2 hÀ1 barÀ1, about 7 times more than that of cross-linked graphene oxide (GO) membranes without adding magnesium ions (GOHDA), while keeping excellent rejection performance
The results indicated that magnesium ions promoted reasonable cross-linking, and improved the stacking of GO sheets to give lower mass transfer resistance channels for water transport in the membranes, resulting in the ultrahigh permeance of the GO membranes

Summary

Introduction

Graphene oxide (GO) is a two-dimensional network with a thickness of one atom, which has great potential in the eld of water treatment because of its excellent hydrophilicity,[1] remarkable stacking property[2] and other unique properties.[3]. Cross-linking with large flexible molecules is a common method to improve the stability and control the interlayer spacing of graphene oxide (GO) membranes, but it still suffers from the limitation of low water flux.

Results

Conclusion