Materials Science and Chemistry

Biography

Biography: Valentin Valtchev

Abstract

Porous materials are those permeable to fluids due to the presence of pores. Amongst different groups of materials the zeolite type materials has the biggest impact on the modern society. Zeolites are crystalline microporous crystals with well define pores with size below 2 nm, large micropore volume and specific surface area, tunable active sites and unique shape selectivity. These properties make zeolites indispensable catalysts and molecular sieves in petroleum refining, petrochemical industry, protection of the environment and as a component of different products used in the household. In the future, their impact will widen and be felt in the processing of heavier fossil and renewable feedstocks, optical and medical applications. The diversified feedstocks, together with the changes in the products demand and environmental regulations, make the design and engineering of zeolite based materials a complex task. In order to address new challenges detail insights in the structure-property relationship of zeolite molecular sieves are indispensable. The talk will provide an overview of the current developments in the field of zeolite-type materials. Both, in-situ and post-synthesis methods of modification of zeolite molecular sieves will be addressed. The advances in the understanding of the nucleation/crystal growth process will be discussed and example how the new knowledge serve to obtain zeolites with predetermined properties will be given. Post-synthesis methods for control of the physicochemical properties of zeolites will also be addressed. For instance, a drawback in the use of zeolites is the restricted diffusion, which is commonly associated with the sub-nanometer size of their pores where the active sites are located. The post-synthesis methods that allow overcoming this roadblock to the more efficient use of zeolites will be overviewed. Finally the complementarily between in-situ and post-synthesis methods with the goal to overcome the natural limits and obtain unique zeolitic materials will be addressed.