Exploring the potential of mesoporous silica, SBA-15, as an adsorbent for light hydrocarbon separation

Equilibrium adsorption isotherms for methane, ethane, ethylene, acetylene, propane, and propylene have been measured for the first time on mesoporous silica, SBA-15, and the data are analyzed by using the Langmuir-Freundlich adsorption isotherm model. The adsorption capacities for ethylene and propylene are found to be higher than those for corresponding alkanes. Likewise, adsorption of acetylene is more pronounced as compared to ethylene. The isosteric heats of adsorption for various adsorbates estimated by the Clausius-Clapeyron equation are higher for olefins and acetylene and are comparable with those reported for pi-complexation based systems. Such a trend has in turn suggested a higher affinity of SBA-15 framework for alkenes over corresponding alkanes, which has been examined in terms of the textural characteristics of SBA-15. It is suggested that SBA-15 can potentially be a good adsorbent for separation of light hydrocarbons.