Ultrathin Membranes: A New Opportunity for Ultrafast and Efficient Separation

Developing advanced membranes with both high permeance and selectivity to enable ultrafast and efficient separation is a persistent pursuit by materials scientists. In recent years, diverse ultrathin membranes with nanometer-scale thickness and unique membrane structures have been developed. These materials show ultrahigh permeance and excellent selectivity in water desalination, dye rejection, oil-water purification, and gas separation applications. Herein, current state-of-the-art ultrathin membranes are introduced, including polyamide membranes, diamond-like carbon membranes, single-walled carbon nanotube network membranes, metal hydroxide nanostrand network membranes, protein membranes, and graphene laminar membranes and their derivatives. The designs, fabrication techniques, and performance advantages of these ultrathin membranes are discussed. A summary of the remaining challenges and potential future directions are also presented.