Comprehensive evaluation of 3A, 4A, 5A, and 13X zeolites for selective 1-octene adsorption over n-octane

Abstract

Among linear α-olefins, 1-octene is widely used as a starting material in the industrial production of plastics, oils, waxes, and surfactants. The adsorption separation of gaseous olefin/paraffin using various adsorbents has been extensively studied; however, detailed studies on the adsorption separation of liquid-phase olefin/paraffin are scant. In this study, we systematically investigated the selective adsorption of 3A, 4A, 5A, and 13X bead-shaped zeolites from 1-octene/n-octane liquid binary mixture as a function of type and weight of the zeolites. Batch-type adsorption experiments were performed in the 1-octene volume fraction range of 10–90 %. The results show that 5A and 13X zeolites are promising adsorbents for selective 1-octene adsorption owing to the preferential adsorption of 1-octene on the cation sites in the micropore. Contrastingly, both 1-octene and n-octane cannot enter 3A and 4A micropores, resulting in negligible preferential adsorption of 1-octene over n-octane. The Langmuir constant of 5A is higher than that of 13X due to the stronger polarization effect of Ca2+ compared to that of Na+, resulting in additional attractive interaction between the adsorbent and 1-octene. The experimental analysis presented in this study provides a solid basis for the development of selective adsorbents for the liquid–liquid separation.