Ideal Desalination through Graphyne-4 Membrane: Nanopores for Quantized Water Transport

TL;DR

This study demonstrates that a graphyne-4 membrane can achieve exceptional desalination performance with high water permeability and complete salt rejection, driven by quantized water transport at the nanoscale.

Contribution

The paper introduces the potential of graphyne-4 as a highly efficient desalination membrane with unprecedented permeability and low energy consumption, supported by molecular dynamics simulations.

Findings

Graphyne-4 achieves 100% salt rejection.

Water permeability is approximately 13 L/cm2/day/MPa, ten times higher than nanoporous graphene.

Water flow exhibits nonlinear, quantized behavior due to nanoscale effects.

Abstract

Graphyne-4 sheet exhibits promising potential for nanoscale desalination to achieve both high water permeability and salt rejection rate. Extensive molecular dynamics simulations on pore-size effects suggest that graphyne-4, with 4 acetylene bonds between two adjacent phenyl rings, has the best performance with 100% salt rejection and an unprecedented water permeability, to our knowledge, of ~13L/cm2/day/MPa, about 10 times higher than the state-of-the-art nanoporous graphene reported previously (Nano Lett.s 2012, 12, 3602-3608). In addition, the membrane entails very low energy consumption for producing 1m3 of fresh water, i.e., 3.6e-3 kWh/m3, three orders of magnitude less than the prevailing commercial membranes based on reverse osmosis. Water flow rate across the graphyne-4 sheet exhibits intriguing nonlinear dependence on the pore size owing to the quantized nature of water flow at the nanoscale. Such novel transport behavior has important implications to the design of highly effective and efficient desalination membranes.