Functional graphene nanosheets: The next generation membranes for water desalination

• Graphenes are exceptional materials for the next generation water separation membranes.
• Graphenes prove ultrafast permeance, excellent mechanical strength and precise ionic sieving.
• Modified NPG and GO membranes showed exceptional antifouling properties.
• Need full understanding of the transport mechanism of NPG and GO membranes
• Mechanical performance of fully wetted NPG and GO membranes must be addressed.

Membrane desalination and water purification technologies have become important energy-efficient means to secure fresh water resources around the globe. Among the significant recent advancements in the design and development of new membrane systems is the use of graphenes. Graphenes have offered a novel class of mechanically robust, ultrathin, high-flux, high selectivity, and fouling resistant separation membranes that provide opportunities to advance water desalination technologies. The facile synthesis of nanoporous graphene (NPG) and graphene oxide (GO) membranes opens the door for ideal next-generation membranes as cost effective and sustainable alternative to the long-existing thin-film composite polyamide membranes for water purification applications. In this review, we highlight the structure and preparation of NPG and GO membranes. We also discuss the recent experiments, computer simulations and theoretical models, addressing the unique mechanical properties, ion selectivity, and possible transport mechanisms through NPG and GO membranes. We will focus on the fabrication and functionalization schemes of graphene oxide membranes. Particular emphasis is on the antifouling properties of the NPG and GO modified membranes. We believe this review will open new avenues for new innovations and applications of NPG and GO in water desalination and treatment.