High Pressure Adsorption Studies of Ethane and Ethylene on Clay-Based Adsorbent Materials

Bentonite clay is tailored in three different ways to produce porous materials viz. PCH1, PCH2, and PILC, where PCH1 and PCH2 are two different clay heterostructures and PILC is a Zr-oxide pillared clay. Surface characterization materials shows that both of PCHs have a higher surface area than PILC, and have micro and mesoporosity, where PILC is basically a microporous. DRIFT and X-ray techniques were used to investigate the surface-groups and height of micropores in PCHs and PILC, respectively. Adsorption isotherms of ethane and ethylene were measured on these materials up to high pressure (1000kPa) under different temperatures, and by processing the obtained data these materials were evaluated for their aptness for ethane ethylene separation. Isosteric heats of adsorption were observed higher for ethylene than ethane during initial surface coverage for each material-gas system. Interaction in each material-gas system with gradual increase in pressure was elucidated with the help of isosteric heat curves. Adsorption performances of these materials were compared with already studied materials (reported by other workers for ethane/ethane separation). Comparison was based on selectivity and working capacity, which are the two decisive parameters for screening suitability of any adsorbent material (for PSA application).