  Sarin is a very lethal synthetic organophosphorated compound that inhibits
the nervous system muscle control. Although not used as a chemical weapon
anymore, it still worries the authorities regarding possible use by terrorists.
Most of the studies about sarin are theoretical/computational due to its high
lethality and are concentrated in its detection and degradation. Few studies
are about air filtration from sarin gas. Here, the potential of graphene
oxide-based membranes to filter air from sarin/air mixtures is investigated by
classical molecular dynamics simulations. Membranes formed by one and two
nanosheets of porous reduced graphene oxide (rGO) were considered. The passage
of sarin and air molecules through these membranes from a highly concentrated
region to an empty one, is evaluated as a function of temperature and sarin/air
relative concentration. Sarin molecules are shown to be trapped by hydroxyl and
carboxyl chemical groups in the nanosheet, while a considerable passage of air
molecules (N$_2$, O$_2$ and Ar) through the membranes was verified. The results
show the capacity of the rGO membranes to retain sarin from passing through,
even at high temperatures, thus indicating their potential to be used as a
filter for sarin gas.
