Molecular dynamics study on electric field-facilitated separation of H2O/O2 through nanoporous graphene oxide membrane

Abstract

The application of external stimuli, such as electric fields, could improve gas separation. Molecular dynamics (MD) simulations were conducted to analyze the dynamic electric field-facilitated separation process of H2O/O2 gas molecules through a double-layered nanoporous graphene oxide membrane. The computational results illustrated an enhanced gas permeation rate of 3.26 × 103 mol·m−2·s−1 for H2O molecules with an external electric field of 10−4 V·Å−1, and an enhanced selectivity of 1.44 over O2 molecules, which was 0.33 in the absence of the external electric field. The mechanism of enhanced H2O/O2 separation has also been illuminated by examining the variation in interaction energy with electric field strength. The electric field inhibits the hydrogen bond interactions between H2O molecules and H2O membranes. Accelerating desorption under electric fields would enable more adsorption sites on the membrane, thereby facilitating H2O molecules permeation.