Time：18th June (Thursday), 2015 P.M. 2:00
Venue：Conference Room of Energy Building
Lecturer：Dr. Valentin Valtchev
Laboratory for Catalysis & Spectrochemistry, ENSICAEN, Caen, France
Introduction of Lecturer:
Valentin Valtchev studied Geochemistry at the University of Sofia and completed his PhD at the Bulgarian Academy of Sciences. He has worked as postdoctoral research fellow in the groups of Prof. Alan Dyer (1992?1993) and Prof. Johan Sterte (1995?1996). In 1996, he was promoted to Senior Researcher at the Bulgarian Academy of Sciences. He moved to France in 1997. At present he is leader of materials science group at the Laboratory of Catalysis and Spectroscopy (LCS) in Caen, France. His research involves synthesis and modification of zeolites and other porous solids that can be used for catalysis, separation, and molecular recognition.
In 2014 together with Dr. Mintova he received Cronstedt award from the Federation of European Zeolite Associations.
Abstract：
The first part of the talk is devoted to the synthesis of nanosized zeolite crystals. Namely, the preparation of nanosized crystals from conventional hydrogel systems that are employed in the industrial production of zeolites will be addressed. New findings on the spatial and temporal location of nuclei in zeolite yielding hydrogel systems will be presented and the rational control of zeolite nucleation discussed.
The second part of the presentation is devoted to the treatment in fluoride medium with the ultimate goal to obtain hierarchical zeolite crystals. Equilibrium in fluoride containing solutions and the formation of very reactive species (FHF-), which are not Al/Si selective, will be discussed. After a proper adjustment of the concentration, non-selective chemical etching of the zeolite framework occurs. The resulting materials combine a secondary porosity with retention of the native compositional and structural characteristics of the parent zeolite, including the Si/Al ratio, the number and the distribution of acid sites.
The industrial perspective for a zeolite material requires a simple treatment that avoids consecutive steps and special equipment. The two presented approaches face this condition, hence it is expected that both nano and hierarchical zeolites could face the industrial challenges in terms of cost, stability and simplicity of processing.
Contact：DNL Office，Jiajia Liu（9842）