PHYSICOCHEMICAL PROPERTIES OF ALKALI-METAL EXCHANGED TYPE X-ZEOLITES

The changes in the physicochemical properties of a series of faujasite type X zeolites cation exchanged with K+, Rb+ and Cs+ have been studi ed by XRD, IR, thermoanalytical methods and sorption measurements. As a consequence of the enhanced scattering of X-rays by larger alkali me tal cations, the percent relative intensity of the XRD peaks of cation exchanged zeolites was found to have decreased considerably. The fram ework IR spectra also showed analogous changes. The alkali metal excha nge was found to enhance the thermal stability of the parent zeolite. The available void volume and specific surface area (obtained by low t emperature nitrogen sorption) also decreased with the increase in the degree of exchange and cationic size. Equilibrium sorption capacities (298 K and P/P0 = 0.5) for water, n-hexane, cyclohexane and 1,3,5-trim ethylbenzene also exhibited the same trend.