posted on 2024-01-03, 04:33authored byShuang Li, Xinke Zhang, Jiaye Su
Improving the desalination performance
of membranes is always in
the spotlight of scientific research; however, Janus channels with
polarized surface charge as nanofiltration membranes are still unexplored.
In this work, using molecular dynamics simulations, we demonstrate
that Janus graphene oxide (GO) channels with appropriate geometry
and surface charge can serve as highly efficient nanofiltration membranes.
We observe that the water permeability of symmetric Janus GO channels
is significantly superior to that of asymmetric channels without sacrificing
much ion rejection, owing to weakened ion blockage and electrostatic
effects. Furthermore, in symmetric Janus GO channels, the transport
of water and ions is sensitive to the charge polarity of the channel
inner surface, which is realized by tuning the ratio of cationic and
anionic functionalization. Specifically, with the increase in cationic
functionalization, the water flux decreases monotonously, while ion
rejection displays an interesting maximum behavior that indicates
desalination optimization. Moreover, the trade-off between water permeability
and ion rejection suggests that the Janus GO channels have an excellent
desalination potential and are highly tunable according to the specific
water treatment requirements. Our work sheds light on the key role
of channel geometry and charge polarity in the desalination performance
of Janus GO channels, which paves the way for the design of novel
desalination devices.