title: Toward understanding the influence of ethylbenzene in p-xylene selectivity of the porous titanium amino terephthalate MIL-125(Ti): adsorption equilibrium and separation of xylene isomers.
abstract: The potential of the porous crystalline titanium dicarboxylate MIL-125(Ti) in powder form was studied for the separation in liquid phase of xylene isomers and ethylbenzene (MIL stands for Materials from Institut Lavoisier). We report here a detailed experimental study consisting of binary and multi-component adsorption equilibrium of xylene isomers in MIL-125(Ti) powder at low (≤0.8 M) and bulk (≥0.8 M) concentrations. A series of multi-component breakthrough experiments was first performed using n-heptane as the eluent at 313 K, and the obtained selectivities were compared, followed by binary breakthrough experiments to determine the adsorption isotherms at 313 K, using n-heptane as the eluent. MIL-125(Ti) is a para-selective material suitable at low concentrations to separate p-xylene from the other xylene isomers. Pulse experiments indicate a separation factor of 1.3 for p-xylene over o-xylene and m-xylene, while breakthrough experiments using a diluted ternary mixture lead to selectivity values of 1.5 and 1.6 for p-xylene over m-xylene and o-xylene, respectively. Introduction of ethylbenzene in the mixture results however in a decrease of the selectivity.
authors.affiliation: Laboratory of Separation and Reaction Engineering, Associate Laboratory LSRE/LCM, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: Mariana A
authors.initials: MA
authors.lastname: Moreira
authors.forename: João C
authors.initials: JC
authors.lastname: Santos
authors.forename: Alexandre F P
authors.initials: AF
authors.lastname: Ferreira
authors.forename: José M
authors.initials: JM
authors.lastname: Loureiro
authors.forename: Florence
authors.initials: F
authors.lastname: Ragon
authors.forename: Patricia
authors.initials: P
authors.lastname: Horcajada
authors.forename: Pascal G
authors.initials: PG
authors.lastname: Yot
authors.forename: Christian
authors.initials: C
authors.lastname: Serre
authors.forename: Alírio E
authors.initials: AE
authors.lastname: Rodrigues