The effect of binder for shaping ZIF-8 on the separation of n-pentane/isopentane: Experimental and theoretical study

In this study, the performance of ZIF-8 for the n-pentane/isopentane separation in the liquid phase was investigated. For this purpose, the adsorption isotherms of n-pentane and isopentane were measured at constant pressure (4 bar) and different temperatures (30, 40 °C). It was found that ZIF-8 selectivity was 9.08. To predict the adsorption behavior of pentane isomers, experimental data were modeled using Langmuir, Freundlich, and Sips isotherms. It was shown that the Sips model has the best agreement with the experimental data. In order to use adsorbents for industrial applications, binders should be added to the powder adsorbent for granular or extruded shaping. In this section of research, the effect of different loading of polyvinyl alcohol (PVA) as the organic binder was investigated. For this purpose, different loadings of 7, 12.5, 20, and 30 %wt of PVA for ZIF-8 were used. Acceptable mechanical strength of the final shaped adsorbent was achieved for ZIF-8 at 20 %wt PVA. Kinetic experimental study showed that the adsorption kinetics of pentane isomers fitted with the pseudo-second-order model. Finally, the equilibrium data of n-pentane/isopentane mixture adsorption including the total amount of adsorption mixture and the individual adsorption amount of each component were predicted using IAST method.