The advent of graphene and other two-dimensional materials in membrane science and technology

In this review, we discuss the potential of graphene and two-dimensional materials "beyond graphene" in membrane science, emphasizing peculiarities, some application fields, open challenges and pitfalls. Two-dimensional materials are envisaged to work as ultrathin membranes with atomic thickness or, alternatively, as nanofillers for composite polymeric membranes. Formation and uniformity of nanopores into two-dimensional materials membranes represent key issues for successful separations. Currently, many efforts are dedicated to identify suitable techniques for massive production of porous graphene nanosheets at competitive costs. Despite a certain discrepancy between molecular modeling and experimental studies exists, the earliest implementations of graphene-based membranes for water desalination, liquid separation and gas purification show superb performances in terms of salt rejection, transmembrane flux and selectivity. Likewise, two-dimensional materials beyond graphene are regarded as promising candidates to work as ultrathin membranes.