Национален център за нови материали UNION и Българската Зеолитна Асоциация
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КОНТРОЛ НА МОРФОЛОГИЯТА И СВОЙСТВАТА НА ЗЕОЛИТНИ КРИСТАЛИ
д-р Валентин Вълчев
Directeur de Recherche
Laboratory of Catalysis and Spectrochemistry, CNRS, Caen, France
на 3 декември 2009 г. (четвъртък) от 11:00 ч. в Заседателната зала
на ХФ на СУ “Св. Климент Охридски” (бул. “Джеймс Баучър” 1)
Zeolite Crystal Engineering
University of Caen, ENSI Caen, University of Caen, 6 boulevard Marйchal Juin, 14050 Caen, FRANCE
New zeolitic materials with pore systems and framework compositions, that could diversify the zeolite applications or improve the existing processes, are highly desired. However, discovery of new zeolites is still an exercise that involves systematic exploration of many reaction variables, and requires a fair degree of serendipity for successful synthesis of new materials. Improving the performance of the already known zeolites is therefore an alternative that merits a lot of attention.
The current presentation reviews the parameters that could have a great impact on the zeolite performance such as: fine tuning of the crystal size, morphology, composition, surface functionality, presence of mesopores, and spatial arrangement (macrostructures) of zeolite crystals.
The first part of the talk, after a short introduction, will be devoted to the control of the crystal size. Fine tuning of particle’s dimensions from nano- to micro- and to millimetre size will be presented. Special attention will be paid to the synthesis of zeolite nanoparticles.
Further, the advantages of zeolites with predetermined crystal faces and the possibility of fine tuning crystal morphology will be presented. The utility of such crystals in the preparation of zeolite macrostructures and thin film will be exemplified.
Template directed synthesis of mesopores zeolites will be review in the third part and alternative methods providing zeolitic materials with hierarchical porous organization will be presented. This part will include a short overview of different templates, including biological specimens, employed in the synthesis of zeolitic materials with multilevel organization.
Zeolite-zeolite core-shell composite that combine the properties of two different structure types will be included in the final part of the talk. Brief examples demonstrating the potential of these materials in the separation and storage or separation and catalytic conversion of organic compounds will be presented.
Finally, how the engineering of zeolite crystal might stimulate future applications of zeolites will be addressed.