Rational
Design of Two-Dimensional Hydrocarbon Polymer
as Ultrathin-Film Nanoporous Membranes for Water Desalination
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Abstract
Membrane-based
water desalination has drawn considerable attention
for its potential in addressing the increasingly limited water resources,
but progress remains limited due to the inherent constraints of conventional
membrane materials. In this work, by employing state-of-the-art molecular
simulation techniques, we demonstrated that two-dimensional hydrocarbon
polymer membranes, materials that possess intrinsic and tunable nanopores,
can provide opportunities as molecular sieves for producing drinkable
water from saline sources. Moreover, we identified a unique relationship
between the permeation and selectivity for membranes with elliptical
pores, which breaks the commonly known trade-off between the pore
size and desalination performance. Specifically, increase in the area
of elliptical pores with a controlled minor diameter can offer an
improved water flux without compromising the ability to reject salts.
Water distributions and water dynamics at atomic levels with the potential
of mean force profiles for water and ions were also analyzed to understand
the dependence of permeation and selectivity on the pore geometry.
The outcomes of this work are instrumental to the future development
of ultrathin-film reverse osmosis membranes and provide guidelines
for the design of membranes with more effective and efficient pore
structures