Sorption of SF/sub 6/ and SF/sub 6/ decomposition products by activated alumina and molecular sieve 13X

Abstract

This paper presents measurements of the adsorption characteristics of various SF/sub 6/ decomposition products on activated alumina and on a molecular sieve type 13X (synthetic zeolite). The adsorption process is analysed by measuring the concentrations of the gas component to be adsorbed as well as its desorbed reaction products by IR absorption in a 2.5 litre stainless steel cell. The adsorption characteristics (adsorption isotherms) and the chemical reactions in the adsorber were determined for the pure gases SF/sub 4/, SOF/sub 2/, SO/sub 2/, SOF/sub 4/, SO/sub 2/F/sub 2/, S/sub 2/F/sub 10/, S/sub 2/O/sub 2/F/sub 10/ and SF/sub 6/. Precharging the adsorber with humidity has been shown to lower the adsorption. The importance of the chemical reaction energy associated with chemisorption processes was established by measuring the temperature of the adsorber substances during the adsorption process. The transport mechanisms responsible for the transfer of the adsorbable gas from the volume into the adsorber (adsorption kinetics, diffusion, convection) were identified by comparing the measured decay times of pure SO/sub 2/ as well as SO/sub 2/ in SF/sub 6/ with and without forced convection. A preliminary attempt is made to understand the physical chemistry of the observed phenomena.