Enhanced quantum sieving of hydrogen isotopes via molecular rearrangement of the adsorbed phase in chabazite

Abstract

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.