Kinetics of adsorption carbonyl sulfide on selexsorb COS

Abstract

The kinetics of adsorption of carbonyl sulfide on Selexsorb COS was studied. Selexsorb COS, an activated alumina adsorbent has been preferably impregnated with the metal compounds and a mixture. The reaction was carried out using a 15 cc. continuous-flow tube reactor under atmospheric pressure. The conversion of carbonyl sulfide at steady-state was analyzed by means of gas chromatography equipped with pulse flame photometric detector. The kinetic parameters were obtained by varying the ratio of adsorbent weight to the flow rate of feed for different carbonyl sulfide concentrations and temperature gradients. The initial rate of adsorption was found to be dependent on the carbonyl sulfide concentration to the power of 1.04. The rate of adsorption at 40 ํC, could be represented by the following expression : -r[subscript cos] = k[COS][supercript 1.04]. The apparent activation energy was 22.4 kJ.mol[superscript -1] and the frequency factor was 468.7 kg[superscript -1].s[superscript -1]. The adsorption was first order with respect to the COS concentration and followed the Langmuir model in the case of low pressure or/and low concentration of the reactant. The rate limiting step was found to be both external diffusion and chemical reaction control, but there was no internal diffusion limitation.