Water desalination and ionic selectivity in kagome-graphene membranes

Nanostructured membranes represent a cutting-edge solution at the forefront of addressing the global water crisis, with great potential to enable next-generation of water desalination technologies. In this scenario, this study investigates the potential of 2- and 3-triangulene Kagome-Graphene (KG) membranes for desalination using Molecular Dynamics (MD) simulations. Simulations were performed with sodium chloride (NaCl) solutions at concentrations of 0.5 M and 1.0 M, under external electric fields (EF) ranging from 0 to 0.53 V nm${}^{-1}$. The results show that

ions exhibit greater mobility than

ions, depending of EF strength and the membrane. In higher fields,

and

migrate in opposite directions, with a nearly complete separation achieved at 0.53 V nm${}^{-1}$. The 2-triangulene membrane exhibits superior ion rejection and selectivity compared to the 3-triangulene membrane, effectively inhibiting ion transport while maintaining water flux, even in the absence of an applied field. Both systems exhibit non-ohmic ionic transport across the entire spectrum of EF examined, although a transition to an ohmic regime is noted in the low-field limit. At EF $<$0.18 V nm${}^{-1}$, nearly complete ion rejection is observed in the 2-triangulene membrane, highlighting its high selectivity and potential for future desalination technologies.