title: An investigation of the crystallization kinetics of zeotype SAPO-34 crystals synthesized by hydrothermal and sonochemical methods.
abstract: The kinetics study of SAPO-34 crystallization from a gel containing morpholine as a structure directing agent (SDA) was investigated by means of X-ray diffraction (XRD) patterns in order to determine the kinetics parameters, i.e. induction times, rate constants, frequency factors, and activation energies for the induction and growth stages. The kinetics data of growth period were determined by using the Avrami-Erofeev nucleation growth model. SAPO-34 molecular sieves were synthesized by using both sonochemical-assisted hydrothermal and conventional hydrothermal heating at temperatures of 180, 200, and 220 °C to elucidate the influence of crystallization method on the crystallization kinetics of SAPO-34. The activation energy values indicated that the crystal growth mechanism was enhanced for samples synthesized sonochemically, whereas the induction energy was not greatly affected by using sonication process. Also, the kinetic compensation effect (KCE) was considered in order to obtain the isokinetic temperature.
authors.affiliation: Faculty of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), P.O. Box 15875-4413, Hafez Ave., Tehran, Iran.
authors.forename: Fariba
authors.initials: F
authors.lastname: Marzpour Shalmani
authors.affiliation: Faculty of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), P.O. Box 15875-4413, Hafez Ave., Tehran, Iran. Electronic address: halladj@aut.ac.ir.
authors.forename: Rouein
authors.initials: R
authors.lastname: Halladj
authors.affiliation: Faculty of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), P.O. Box 15875-4413, Hafez Ave., Tehran, Iran.
authors.forename: Sima
authors.initials: S
authors.lastname: Askari
keywords: Activation energy; Avrami–Erofeev model; Crystallization kinetics; Sonochemical crystallization; Zeotype SAPO-34