Removal of cyclopentadiene from 1-octene by transition metal containing zeolites – Part 2: Stabilization of CoCaX zeolite by its cation distribution

Zeolite X successively exchanged with Ca2+ and Co2+ ions is an efficient absorbent for traces removal of cyclopentadiene from alkene mixtures. To understand this affinity and stability of the aluminosilicate with this combination of cations, detailed structure analyses of samples after ion exchange, calcination, and exposure to guest molecules have been performed. Rietveld analysis of X-ray powder diffractograms of samples of known composition revealed stabilizing effects of the cation distribution in the studied samples and the irreversible blocking of Ca ions in hidden structure positions, resulting in positioning of Co ions at positions available for interaction with guest molecules like 1-octene and cyclopentadiene.