Graphene and graphene oxide (GO) have attracted much attention on separation membrane due to their unique properties. In this paper, we review the membrane modification methods by graphene and GO, including membrane blending with GO, nanoporous graphene membrane and layered GO membrane, and comprehensively analyze the performances and mechanisms of these modified membranes. The results show that the blending membrane prepared via the phase inversion method exhibits high water flux, proper solute rejection, excellent hydrophilicity and low fouling propensity, but the unique structure and property of GO does not play effectively in the blending membrane with GO and modified GO; nanoporous graphene membrane has good separation performances because of graphene's high mechanical strength, atomic thickness and ability to support subnanometre pores, but it is challenging to manufacture large graphene with maintaining the structural integrity and control the pore size and pore distribution; the particular properties of GO get the full play in layered GO membranes, which achieve high water flux mainly because the non-oxidized region of GO with nearly frictionless surface promotes the extremely fast flow of water molecules, and obtains high rejection because of rejecting unwanted solutes. Accordingly, layered GO membrane will be thought as a promising membrane separation technology to obtain fine performances of high permeability, selectivity and anti-fouling ability.

Contents
1 Introduction
2 Membrane blending with GO
2.1 Membrane blending with GO directly
2.2 Membrane blending with chemical modified GO
2.3 Membrane blending with GO and other nanomaterials
3 Nanoporous graphene membrane
4 Layered GO membrane
4.1 Fabrication methods of layered GO membrane
4.2 Mechanism of layered GO membrane
5 Conclusion and outlook