High-Flux High-Selectivity Metal-Organic Framework MIL-160 Membrane for Xylene Isomer Separation by Pervaporation.

Separation of p-xylene (kinetic diameter ca. 0.58 nm) from its bulkier isomers (o-xylene and m-xylene, ca. 0.68 nm) is challenging, but important in the petrochemical industry. Herein, we developed a highly selective and stable metal-organic framework (MOF) MIL-160 membrane for selective separation of p-xylene from its isomers by pervaporation. The suitable pore size (0.5∼0.6 nm) of the MIL-160 membrane selectively allows p-xylene to pass through, while excluding the bulkier o-xylene and m-xylene. For the separation of equimolar binary p-/o-xylene mixtures at 75 °C, high p-xylene flux of 467 g m-2  h-1 and p-/o-xylene selectivity of 38.5 could be achieved. The stability of MIL-160, ensured the separation performance of the MIL-160 membrane was unchanged over a 24 h measurement. The high separation performance combined with its high thermal and chemical stability makes the MIL-160 membrane a promising candidate for the separation of xylene isomers.