Understanding of the nucleation of zeolites continues to be one of the main targets in its chemistry. In spite of the huge effort done by scientific community in this field and the high number of the characterization techniques used, the information relate d to the nature of the species involved in the nucleation is generally scarce, which is the main limitation for advancing in the knowledge of crystallization processes. We propose a study trying to overcome this disadvantage, that is, using a priori knowing the Si species that will cause the crystallization. Those are called pre-structured species since they contain some of the subunits that will be present in the final crystalline phase. Starting from gels containing these well-known species that can poten tially act as nuclei in the formation of a particular zeolite, it would be relatively easy to follow the crystallization processes. In particular, for systems in which some evidences on the growing have been clear in the literature, we will start from the linear or layered species that joining together generate the final tri-dimensional structure. In this sense, the case of MCM-22 zeolite could be an adequate system to be studied as starting point. A proper characterization following the crystallization wou ld be as important, if no more, as synthesis itself in the development of this project. Consequently, a systematic characterization by both in-situ and ex-situ techniques is planned. Thus, in-situ synchrotron-radiation techniques such as combined small and wide-angle X-ray scattering (SAXS/WAXS) and energy-dispersive X-ray diffraction (EDXRD), can give us essential information on the first stages of the nucleation and kinetics of crystallization, respectively; ex-situ 27Al and 29Si solid and liquid NMR woul d allow us to go deeply into the transformation suffered by the particular atoms constituting those nuclei in the process of generating the final zeolite.
Field of science
- /natural sciences/earth and related environmental sciences/geology/mineralogy/crystallography
Call for proposal
See other projects for this call