Impact of the BEA zeolite morphology on isobutane adsorption followed by Reversed-Flow Inverse Gas Chromatography

► The influence of the zeolite aggregates and particle sizes both on the values of the effective and surface diffusion coefficients. ► Local determination of various physicochemical quantities like the energetic distribution and surface coverage of i-C4 on HBEA zeolite. ► The use of the Reversed-Flow Gas Chromatography technique to the fundamental and time-resolved studies of gas/zeolite interactions. ► Insights of the influence of the intercrystalline diffusion on the heterogeneous catalysis properties of HBEA zeolite. The mass transfer phenomena of isobutane (i-C4) were investigated at 343K on three protonic BEA zeolites. Defined by their crystallites sizes and degrees of aggregation, these samples were characterized by Reversed-Flow Inverse Gas Chromatography (RF-GC). This simple technique, used in conjunction with numerical computation, allowed the determination of physicochemical quantities like local monolayer capacities, probability density functions and diffusion coefficients in a time-resolved way. This study enabled to conclude that the effective diffusion coefficient was affected by the size of the zeolite agglomerate whereas the surface diffusion depended on the zeolite crystallite size.