Topic of Research Seminar: A comparative study of the Desilication of Channel- and Cage-like Zeolites

Abstract: Zeolites are very important catalysts in the chemical industry, but their intrinsic narrow micropore system often restricts the mass transport of reactant and product molecules. These mass transport limitations can be overcome by introducing a second larger pore system (meso-/macropores) into the zeolite crystals. Over the past decade, desilication of zeolites has emerged as a simple post-synthetic process to implement mesoporosity into zeolites. Here we present the investigation of the influence of framework topology on the formation of mesoporosity by the desilication process. For this purpose, the desilication behaviour of a channel-like system (ZSM-5/MFI-type) and a cage-like system (SSZ-13/CHA-type) are compared. It has been found that cage-like zeolite (SSZ-13) is more susceptible to the desilication process. The desilication of SSZ-13 zeolite resulted in drastic reduction of microporosity and crystallinity, while the microporosity and crystallinity of ZSM-5 gradually decreased with desilication time. By systematically studying the influence of various desilication parameters (e.g. treatment time, temperature and alkaline concentration), it has been found that there exists a direct correlation between the extraction of silicon and mesoporosity formation for the channel-like zeolite (ZSM-5) whereas in case of cage-like zeolite (SSZ-13) no direct correlation has been found.

Subject Field of Topic: Heterogeneous Catalysis

Name of Speaker: Dr. Ameen Shahid

Professorial Rank of Speaker: Assistant Professor

University Email of Speaker: [email protected]

Research Group Weblink or University Profile weblink: https://scme.nust.edu.pk/faculty/ameen-shahid/

Affiliation of Speaker: NUST School of Chemical and Materials Engineering (SCME)

Date of Seminar: 26 May 2022 at 1400 hrs

Venue: SCME Seminar Hall