Adsorption of Light Hydrocarbons on LTA

This paper reports the results of an experimental study on adsorption of light hydrocarbons on small pore microporous materials. The choice of hydrocarbons studied was affected taking into consideration the application of adsorption processes in removal of light hydrocarbons from exhaust streams of the petrochemical industry and of light-duty gasoline vehicles under cold start conditions (C4 - C5 paraffins and olefins). The materials investigated were 5A and Ferrierite zeolites, characterized by different pore opening and Si/Al ratio. Equilibrium isotherm curves at room temperature were determined by a gravimetric method on dehydrated zeolites, while breakthrough curves in dynamic tests were used to evaluate the adsorption properties of hydrated zeolites at low hydrocarbon partial pressure (0 - 1 kPa) and in experimental conditions close to those of a HC trap at the engine exhaust. The experimental results regarding the adsorption capacities were discussed with the aim to understand how the physico-chemical characteristics of the adsorbent material could affect its trapping capability in adsorbing different types of hydrocarbons.