The diffusive transport of water, methanol, ethanol, butene, benzene and toluene through porous bodies of compacted, microcrystalline zeolite of type NaX was studied by slow neutron transmission at ambient temperature and pressure. The observed moving profiles of density could be understood in terms of solutions of a nonlinear diffusion equation containing a drift term. The experimental data were interpreted with diffusivities in the order of magnitude of 10−10m2/s and drift velocities of about 10−6m/s.

Diffusive Transport of Fluids through Porous Solids Observed by Neutron Transmission. R.Stockmeyer: Microporous Materials, 1993, 1[6], 383–91

Figure 15

Diffusivity of Ni in 1.87Y Zeolite