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 degrees C and I atm, the equilibrium adsorbed amount for C2H4 is 1.48 mmol/g, and the equilibrium adsorption ratio for C2H4/C2H6 is 6.4. The adsorption capacity is completely restored at 100-105 degrees C, although small residual amounts exist after desorption at 25 degrees C and 75 degrees C. For the adsorption encompassing both physical adsorption and pi-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.