Observation of intraparticle transport barriers in FAU/EMT intergrowth by pulsed field gradient NMR

Pulsed field gradient (PFG) NMR technique with high (up to 30 T/m) gradient amplitudes was employed to study diffusion of isooctane and isobutane in a FAU/EMT intergrowth as well as in the corresponding pure zeolites of the FAU and EMT types. The temperatures and diffusion times used in the measurements were sufficiently small to allow performing diffusion studies for the length scales of sorbate displacements smaller than or comparable with the sizes of the individual zeolite particles. Analysis of the PFG NMR data obtained for the FAU/EMT intergrowth and the comparison of these data with the corresponding results of the measurements of the pure FAU and EMT zeolites revealed the existence of intraparticle transport barriers in the FAU/EMT intergrowth. Partially blocked micropore openings at the interfaces between the intergrowth components of the FAU/EMT particles can be the structural origin of the observed barriers.