Collect. Czech. Chem. Commun.
1998, 63, 321-337
https://doi.org/10.1135/cccc19980321
Sorption and Transport of Species in Silicalite Study of Binary Systems Containing Iodine
Vladimír Masaříka, Pavel Nováka, Arlette Zikánováa, Jan Kornatowskib, Jaroslav Maixnerc and Milan Kočiříka
a J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague 8, Czech Republic
b Institute of Technical Chemistry and Heterogeneous Catalysis, Technical University of Rheinland-Westfalen, D-52074 Aachen, Germany, and Faculty of Chemistry, N. Copernicus University, PL-87-100 Toruñ, Poland
c Prague Department of Institute of Chemical Technology, 166 28 Prague 6, Czech Republic
Abstract
Sorption of iodine from both the vapour phase and iodine solutions in organic solvents on large Silicalite-1 crystals was investigated. The single component sorption of iodine and sorption from binary mixtures under co-diffusion conditions led to a uniform colouring of the crystals. Under counter-diffusion conditions with crystals saturated initially with vapour of a selected solvent, the sorption kinetics of iodine was 2 or 3 orders of magnitude slower as compared with the corresponding co-diffusion experiment. Colouring of crystals was always, at least in its initial stage, non-uniform with visualized pyramids at crystal basal planes. This finding together with the nature of outer and inner crystal morphology suggests that our Silicalite-1 crystals are 90°-intergrowths which have only pore mouth openings of sinusoidal channels in the crystal surface. The process of crystal colouring under counter-diffusion conditions seems to proceed via diffusion along the boundaries of crystal sections.
Keywords: Silicalite-1; Iodine; Binary sorption; Diffusion; Zeolites.
