Atom‐Thick Membranes for Water Purification and Blue Energy Harvesting

International audienceMembrane‐based processes, namely, water purification and harvesting of osmotic power deriving from the difference in salinity between seawater and freshwater are two strategic research fields holding great promise for overcoming critical global issues such as the world growing energy demand, climate change, and access to clean water. Ultrathin membranes based on 2D materials (2DMs) are particularly suitable for highly selective separation of ions and effective generation of blue energy because of their unique physicochemical properties and novel transport mechanisms occurring at the nano‐ and sub‐nanometer length scale. However, due to the relatively high costs of fabrication compared to traditional porous membrane materials, their technological transfer toward large‐scale applications still remains a great challenge. Herein, the authors present an overview of the current state‐of‐the‐art in the development of ultrathin membranes based on 2DMs for osmotic power generation and water purification. The authors discuss several synthetic routes to produce atomically thin membranes with controlled porosity and describe in detail their performance, with a particular emphasis on pressure‐retarded osmosis and reversed electrodialysis methods. In the last section, an outlook and current limitations as well as viable future developments in the field of 2DM membranes are provided