Graphene-Based Membranes for Nanofiltration

Graphene is a well-known, two-dimensional material that exhibits preeminent electrical, mechanical, and thermal properties. Graphene and its derivatives (e.g. graphene oxide) have become emerging nanobuilding blocks for separation membranes featuring distinct laminar structures and tunable physicochemical properties. The atomic thick graphene is able to minimize transport resistance and thus maximize permeate flux of the resulting membrane. Extraordinary molecular separation properties, especially for nanofiltration, have been demonstrated by graphene-based membranes, which attract a lot of interest during the past few years. This chapter aims at presenting the advances in both the theoretical and experimental chemical science and engineering of graphene-based membranes for nanofiltration, including their principles, design, fabrication, and application. Three types of graphene-based membrane materials, nanoporous graphene, graphene oxide (GO), and reduced GO (rGO), are classified. Strategies for controlling the graphene-based membrane microstructure will also be discussed. Moreover, this chapter provides a critical view on the current understanding of the transport behavior and separation mechanism of nanofiltration membranes made of porous graphene layers, graphene laminates, and graphene composites. Finally, the chapter is concluded with the main challenges to be overcome in order to realize the full potential of graphene-based materials in real-world applications.