Effect of inhomogeneous structure on the water desalination performance of graphitic carbon nitride nanochannels: A molecular dynamics study

Abstract

The transport behaviors of aqueous solution in two-dimensional (2D) nanomaterial-based separation membranes are correlated with the structure of the nanoconfined geometry. However, little is known about the impact of asymmetric structures on the transport behavior of aqueous solutions in membranes. In this work, we use molecular dynamics (MD) simulations to investigate the transport behaviors of aqueous solution in non-parallel stacked graphitic carbon nitride (g-C3N4) nanochannels. Interestingly, the non-parallel stacking of g-C3N4 could lead to the local aggregation of water, resulting in an inhomogeneous density distribution within the nanochannel. The high-density region in g-C3N4 nanochannel significantly disrupted the continuum fluid of water. Moreover, the inhomogeneous density distribution of water could impede ion transport in the non-parallel g-C3N4 nanochannel. It was found that ions cannot maintain compact hydration structures in the high-density region. This work reveals the unique properties of slightly tilted membrane structures, providing novel perspective for the design of next-generation nanofluidic devices.