Permeation of water through the membrane was attributed to swelling of graphite oxide structure which enables water penetration path between individual graphene oxide layers. The interlayer distance of dried graphite oxide was reported as 6.35 Å, but in liquid water it increased to 11.6 Å. Remarkably, the paper also cited the inter-layer distance in diluted NaOH as infinity thus reporting dispersion of graphite oxide on single-layered graphene oxide sheets in solution. The study also reported permeation rate of membranes for water 0.1 mg per minute per square cm. The diffusion rate of water was evaluated as 1 cm/hour. Boehm's paper also showed that graphite oxide can be used as cation exchange membrane and reports measurements of osmotic pressures, membrane potentials in KCl, HCl, CaCl2, MgCl2, BaCl2 solutions. The membranes were also reported to be permeable by large alkaloid ions as they are able to penetrate between graphene oxide layers.