New force field for GCMC simulations of D 2 /H 2 quantum sieving in pure silica zeolites
International audience; We report a study on adsorption and coadsorption of H2 and D2 in FAU, MFI and CHA pure silica zeolites having different pore sizes and shapes. Adsorption capacities, selectivities, enthalpies and entropies are determined by combining experiments and GCMC simulations. We show that the force fields available in the literature cannot predict the adsorption equilibria below 77 K with sufficient accuracy. Here we propose a new force field adjusted by using our experimental data obtained for the pure silica MFI zeolite at 65 K and 77 K. With this new force field, it is possible to predict the adsorption and coadsorption equilibria on the three zeolite structures in a tempe…
Quantum Effects on the Diffusivity of Hydrogen Isotopes in Zeolites
The molecular sieving of H2 and its isotopes produced by nuclear plants is a long-standing research where some adsorption processes are well identified. However, some mechanisms governing the diffu...
Enhanced quantum sieving of hydrogen isotopes via molecular rearrangement of the adsorbed phase in chabazite
Coadsorption experiments reveal an unexpected increase of the D2/H2 selectivity with loading in pure silica chabazite at 47 K. This effect is correlated with the appearance of a step in the adsorption isotherms of H2 and D2. Grand canonical Monte Carlo simulations show that this phenomenon is related to a molecular rearrangement of the adsorbed phase induced by its strong confinement. In the case of a H2 and D2 mixture, this rearrangement favors the adsorption of D2 having a smaller size due to quantum effects.