Modification of Resin-Type Adsorbents for Ethane/Ethylene Separation

Modified adsorbents, Ag⁺-exchanged resins, have been prepared and studied for ethane/ethylene separation by adsorption. On Ag⁺-exchanged Amberlyst 35 (36.5% exchange) at 25°C and 1 atm, the equilibrium adsorbed amount for C₂H₄ is 1.48 mmol/g and the equilbrium adsorption ratio for C₂H₄/C₂H₆ is 6.4. The adsorption capacity is completely restored at 100-105°C, although small residual amounts exist after desorption at 25°C and 75°C. For the adsorption encompassing both physical adsorption and π-complexation with energy heterogeneity, the equilibrium data are correlated with an equilibrium isotherm equation employing two fitting parameters. The fitted results agree well with the experimental data. Furthermore, the isosteric heats of adsorption and the diffusion time constants are calculated from experimental data. Considering all adsorption characteristics, these adsorbents show potential for application employing cyclic adsorption processes.