Naslov
Kinetic Analysis of the Formation of Low-Carnigieite from Zeolite Na-A [LTA]

Autori
Kosanović, Cleo ; Subotić, Boris ; Ristič, Alenka ; Kranjc Edi

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Eleventh Slovenian-Croatian Crystallographic Meeting - Book of Abstracts / Golobič, Amalija; Leban,Ivan; Meden Anton - Ljubljana : Univerza v Ljubljani, 2002, 45-45

Skup
Eleventh Slovenian-Croatian Crystallographic Meeting

Mjesto i datum
Bohinj, Slovenija, 27.06.2002. - 30.06.2002

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Zeolite NaA; Low-carnegieite; Kinetics; Formation; Amorphization

Sažetak
Kinetics of isothermal amorphization of zeolite A and recrystallization of the amorphous phase to low-carnegieite at three different temperatures were investigated by powder X-ray diffraction method. Changes in the fractions ZA of zeolite A, Am of the amorphous phase and L-Carn of low- carnegieite during heating of zeolite A at 1078 K (Fig.1) show that amorphization and recrystallization take place simultaneously. Both kinetics of amorphization and recrystallization can be mathematically described by the Johnson–Mehl-Avrami-Kolmogorov (JMAK) kinetic equation, i.e., f(t) =1-exp[-K(T)tn], where f(t) = ZA or L-Carn is the fraction of zeolite A and low- carnegieite, K(T) is the rate constant, t is the time of transformation and n is determined by the mechanisms of nucleation and crystal growth. Plotting [ln(-ln(1-f(t))] vs lnt, the values of K(T) and n as well as the activation energies of amorphization and recrystalization are obtained. The mechanisms of amorphization and recrystallization are discussed in terms of the characteristic numerical values of K(T) and n.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA