| Issue |
Korean Journal of Chemical Engineering,
Vol.8, No.4, 235-239, 1991
Vol.8, No.4, 235-239, 1991
UN/VIS DIFFUSE REFLECTANCE SPECTROSCOPIC
(DRS) STUDY OF COBALT-CONTAINING Y ZEOLITES DEHYDRATED AT ELEVATED TEMPERATURES
(DRS) STUDY OF COBALT-CONTAINING Y ZEOLITES DEHYDRATED AT ELEVATED TEMPERATURES
The coordination changes of Co2+ in Y-zeolite prepared by ion-exchange and dehydrated at various temperatures, have been investigated by UV/VIS diffuse reflectance spectroscopy. Fully hydrated zeolites show an octahedral coordination of [Co(H2O)6]2+ in the supercage with some inter-action with the framework. During dehydration at high temperatures, Co2+ in Y-zeolite changes its coordination, first from a symmetric to distorted tetrahedral and, successively, to an octahedral coordination. Fully hydrated sample of impregnated cobalt nitrate in Y-zeolite shows an octahedral coordination of Co(H2O)6(NO3)2. During dehydration at high temperature, the cobaltous nitrate decomposes to the cobalt oxide. However, the small amount of cobalt ions in cobalt nitrate are ion-exchanged simultaneously.
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