Abstract
The performance of graphene oxide framework (GOF) membranes for water desalination
is assessed using classical molecular dynamics (MD) simulations. The coupling between water
permeability and salt rejection GOF membranes is studied as a function of linker concentration
n, thickness h and applied pressure DP. The simulations reveal that water permeability in
GOF-(n,h) membranes can be tuned from 5 (n = 32 and h = 6.5 nm) to 400 L/cm2/day/MPa
(n = 64 and h = 2.5 nm) and follows the law Cnhan . For a given pore size (n = 16 or 32),
water permeability of GOF membranes increases when the pore spacing decreases, whereas
for a given pore spacing (n = 32 or 64), water permeability increases by up to two orders of
magnitude when the pore size increases. Furthermore, for linker concentrations n 32, the high water permeability corresponds to a 100% salt rejection, elevating this type of GOF membrane
as an ideal candidate for water desalination. Compared to experimental performance of
reverse osmosis membranes, our calculations suggest that under the same conditions of applied
pressure and characteristics of membranes (DP 10 MPa and h 100 nm), one can expect a
perfect salt rejection coupled to a water permeability two orders of magnitude higher than
existing technologies, i.e., from a few cL/cm2/day/MPa to a few L/cm2/day/MPa.
