Pore-Discriminative Pervaporation of Xylene Isomers Through In Situ Synthesized MIL-100(In) Membranes

Efficient xylene isomers' separation remains a challenge due to their similar kinetic diameter and boiling points, particularly for the separation of the immediate size of meta-xylene (MX). A metal-organic framework (MOF) membrane offers the opportunity to realize the isomers' separation due to the highly tunable pore size and pore environment. Herein, an In-based hierarchic MOF (MIL-100) with a size of 0.77 nm was screened, aiming at the realization for isomer separation through pore size matching. Meanwhile, the polar microenvironment in the MOF channel built through trimesic acid ligands contributes to the higher affinity to the MX relative to the PX. With the equimolar feed mixture of MX/PX, the optimal membrane demonstrated a total flux of 7.6 kg·m^-2·h^-1 and an MX/PX separation factor of 2.54 at room temperature through pervaporation. Such performance highly indicates the possibility for efficient liquid xylene separation in future.