Adsorption characteristics of nitric oxide on various adsorbents determined by gas—solid chromatography

Abstract

The adsorption of nitric oxide on 13X and 5A molecular sieves, alumina (boehmite) and nickel—kieselguhr and copper oxide—zinc oxide catalysts was studied by using a chromatographic technique. Moment analysis was used for determining the adsorption equilibrium constant K A. The nitric oxide is purely physically adsorbed on 13X molecular sieve and alumina in the ranges of temperature between 50 and 100 °C and between −8 and 50 °C respectively. The adsorption capacities of 13X molecular sieve and alumina are 0.5 cm 3 g −1 and 1.0 cm 3 g −1 respectively at 50 °C. The nitric oxide reacts with 5A molecular sieve and changes its adsorption capacity with time from 3.4 cm 3 g −1 for fresh adsorbent at 100 °C. For the nickel—kieselguhr catalyst the adsorption of nitric oxide at 50 °C and 110 °C takes place on two kinds of active sites with slow and fast reversible adsorption respectively. The total equilibrium constant, for fast and slow adsorption, is 0.90 cm 3 g −1 at 50 °C and 0.32 cm 3 g −1 at 110 °C. The nitric oxide reacts with the copper oxide—zinc oxide catalyst between 50 and 200 °C and changes the physical properties of the bed probably as a result of shrinkage of the particles. Therefore, quantitative data could not be obtained for this system.