Engineered Graphene Grain Boundaries as Molecular Sieves for Water Desalination

Engineered defects in graphene films using chemical etching or ion beam atomic removal techniques have been used for molecular sieves with tremendous potential. However, scalability over large areas is a hurdle for most of the techniques previously reported. Here we investigate, using first principles, the defect structure of graphene grain boundaries for their potential to act as molecular sieves. We show that, much like pristine graphene grains, general grain boundaries of graphene with (1,0) dislocations are also impermeable to water. Larger defects, when forcefully engineered, turn hydrophilic and can permeate water with a reasonable kinetic barrier.