THE BASICITY AND ACIDITY OF BETA ZEOLITES AFTER ION-EXCHANGE WITH ALKALI METAL CATIONS: A PHYSICOCHEMICAL CHARACTERIZATION

Wong Kah Man¹, Hadi Nur², Abdul Rahim Yacob¹ and Zainab Ramli¹

¹Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia
²Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia

Abstract
The structure, basicity and acidity properties of the alkali metals (Na, K and Cs) exchanged zeolite beta were investigated in this work. Infrared (IR) and X-ray diffraction (XRD) were used for structural characterizations, while Temperature programmed desorption (TPD) of CO2 and NH3 were use for the determination of basicity and acidity, respectively. Results reveal that the framework structure of zeolite beta is retained after the exchange but with a successive decrease in the relative crystallinity after the modification. The acidity of zeolite beta was strongly affected by the crystallinity of the ion-exchanged zeolite beta, in which the acidity has decreased significantly with the decrease in the crystallinity. However, the basicity after the exchange was not very significant in comparison to the acidity. The effect of the crystallinity and the type of alkali metal cations on basicity is also shown.

Publication : Physics Journal IPS A7 (2004) 0211 » page of Content » send to a friend » printed version » request for hard-copy Full paper : open license in format PDF (181.835 byte) Contact : Hadi Nur Additional info : 6 pages, language English » accessed 15.444 times