凯发

Demand of a perfect molecular-level separating membrane with ultra fast permeation and a robust mechanical property for any kind of species to be blocked in water purification and desalination is urgent. In recent years, due to their intrinsic characteristics, such as a unique mono-atom thick structure, outstanding mechanical strength and excellent flexibility, as well as facile and large scale production, graphene and its large family of two-dimensional (2D) materials are regarded as ideal membrane materials for ultra fast molecular separation. A perfect separation membrane should be as thin as possible to maximize its flux, mechanically robust and without failure even if under high loading pressure, and have a narrow nano channel size distribution to guarantee its selectivity. The latest breakthrough in 2D material-based membranes will be presented both in theories and experiments, including their current state-of-the-art fabrication, structure design,simulation and applications. Special attention will be focused on the design and strategies employed to control micro structures to enhance permeation and selectivity for liquid separation.In addition,critical views on the separation mechanism within two-dimensional material-based membranes will be provided based on a discussion of the effects of intrinsic defects during growth, predefined nano pores and nano channels during subsequent fabrication processes, the inter layer spacing of stacking 2D material flakes and the surface charge or functional groups.Furthermore, we will summarize the significant progress of these 2D material-based membranes for liquid separation in nano filtration and ultra filtration.