The efficiency of different technological processes where nanoporous carbons were used depended upon their storage capacity and an appropriate gas transport. Different experimental and theoretical works that related storage to global structural parameters of the solid such as specific surface area or total pore volume (Vt) could be found in the literature. The structure-transport relationships were less studied. The combined use of the truncated pore network model (TPNM) and the kinetic Monte Carlo (KMC) method was proposed in this work to find hydrogen and methane effective self-diffusivities (Deff) and to delve into those relationships. It was found that for Knudsen and free molecular diffusion in the simulated materials, the Deff/Vt versus specific surface area graphic nearly follows a power law. The KMC/TPNM approach was also used to predict the self-diffusion coefficients of hydrogen in Vulcan XC-72 and of methane in a carbon aerogel. The obtained values were within the expected range. KCM/TPNM was computationally fast and it allows a study of the diffusion synchronously and globally in the network, avoiding thus its fractionation in single pores and the use of just one geometric model to describe the porous spaces.A Kinetic Monte Carlo Approach to Diffusion in Disordered Nanoporous Carbons. Ramírez, A.: Chemical Engineering Science, 2011, 66[22], 5663-71

Table 5

Self-diffusion coefficients in C nanotubes at zero loading