Separation of Hexane Isomers in ZIF-8 by Fixed Bed Adsorption

The performance of porous metal organic framework ZIF-8 in the separation of all five hexane isomers (nC6, 2MP, 3MP, 23DMB, 22DMB) is evaluated through a series of multicomponent breakthrough adsorption experiments, at the temperatures of 373, 423, and 473 K and up to total hexane isomers pressure of 0.5 bar. The reported data show for all experiments the following sorption hierarchy: nC6 ≫ 2MP > 3MP ≫ 23DMB > 22DMB. At the temperature of 373 K and total hydrocarbon pressure of 0.5 bar the mixture loading of hexane isomers can go up to 2.15 mol·kg–1. In addition, at the same temperature the selectivities measured by the ratio of the loadings between linear plus monobranched (nC6, 2MP, 3MP) relatively to the dibranched (23DMB, 22DMB) isomers range between 34–55. The results also show that the sorption of nC6 is equilibrium based in contrast with the sorption of branched isomers which is kinetically controlled. The dibranched isomer 22DMB is practically excluded from the framework followed closely by 23DMB....