UiO-66-NH2 hosts a triangular aperture of ~6 Å (Figure ), a dimension well-suited for selective transport of common salt ions dissolved in water. To investigate this, 4.7-nm thick non-vdW 2D UiO-66-NH2 films were deposited on porous graphene where the latter hosted an average pore size of 2.0 nm (Figure ), large enough to permeate hydrated ions without selectivity. The UiO-66-NH2 film was deposited by floating porous graphene on top of the synthesis solution (Figure ). To ensure that graphene does not crack during the deposition, it was mechanically reinforced with a thin film of nanoporous carbon (NPC)/Nafion (support film) similar to a recent report (Figure and). Films were placed in between two annular gaskets with a diameter of 8 mm (Figure ), and were sealed between the two reservoirs of an H-type cell (Figure ). The UiO-66-NH2 side of the film contacted 1 M salt solution (feed side), while the other side contacted Milli-Q water (permeate side, Figure , Supplementary note 8).