Sorption of SF6 and SF6 decomposition products by activated alumina and molecular sieve 13X

This paper presents measurements of the adsorption characteristics of various SF₆ 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 SF₄, SOF₂ , SO₂, SOF₄, SO₂F₂, S ₂F₁₀, S₂O₂F₁₀ and SF₆. “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 SO₂ as well as SO ₂ in SF₆ with and without forced convection. A preliminary attempt is made to understand the physical chemistry of the observed phenomena