Role of subcolloidal (nanozized) precursor species in the early stage of the crystallization of zeolites in heterogeneous systems

Ren, Nan; Bosnar, Sanja; Bronić, Josip; Dutour Sikirić, Maja; Mišić Radić, Tea; Svetličić, Vesna; Antonić Jelić, Tatjana; Hadžija, Mirko; Subotić, Boris (2014) Role of subcolloidal (nanozized) precursor species in the early stage of the crystallization of zeolites in heterogeneous systems. Langmuir, 30 (28). pp. 8570-8579. ISSN 0743-7463

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Abstract

A critical analysis was carried out for the purpose of understanding the role of subcolloidal (nanosized) (alumino)silicate precursor species in the early stage of crystallization of zeolites in heterogeneous systems (hydrogels). The formation and evolution of these subcolloidal species in both the solid and the liquid phases were investigated by various experimental methods such a scanning electron microscopy (SEM, FE-SEM), transmission electron microscopy, atomic force microscopy, particle size analysis, pH measurement, atomic absorption spectroscopy, and dynamic light scattering, after careful separation of intermediates from reaction mixture by two-step centrifugation treatment. The results revealed that a chain of processes (i) the formation of low-molecular-weight (LMW) silicate species, by dissolution of Al-enriched amorphous silica, and their aggregation into about 3 nm sized primary precursor species (PPSs), (ii) the formation of larger (3 to 15 nm sized) silicate precursor species (LSPSs) by a rapid aggregation/coalescence of PPSs, (iii) the formation of “gel” (primary amorphous precursor) by a random aggregation of LSPSs at room temperature, and (iv) the formation of the worm-like particles (secondary amorphous precursor) occurred in the solid phase during heating of the reaction mixture (hydrogel) from room temperature to 170 °C. It is interesting that almost the same processes occur in the liquid phase but with decreased rate according to the relative low concentration of LMW silicate species. With the above described findings, it is highly expected that the manipulation of crystallization pathway through controlling the formation/evolution of precursor species in the initial stage of the process can be achieved.

Item Type:	Article
Uncontrolled Keywords:	zeolite crystallization; heterogeneous systems; early stage; subcolloidal precursor species; worm-like particles
Subjects:	NATURAL SCIENCES > Chemistry > Physical Chemistry
Divisions:	Division of Materials Chemistry
Projects:	Project title Project leader Project code Project type Dobivanje struktura nalik Langerhansovim otočićima iz matičnih stanica miša- Mirko Hadžija 098-0982464-2460 MZOS Površinske sile na atomskoj skali u istraživanju mora i nanotehnologiji- Vesna Svetličić 098-0982934-2744 MZOS Studij utjecaja svojstava alumosilikatnih prekursora na njihove transformacije- Josip Bronić 098-0982904-2953 MZOS
Depositing User:	Tatjana Antonić Jelić
Date Deposited:	20 Dec 2016 16:23
URI:	http://fulir.irb.hr/id/eprint/1907
DOI:	10.1021/la5012296

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