Hybridization of metal–organic framework and monodisperse spherical silica for chromatographic separation of xylene isomers

Abstract

Abstract Metal–organic frameworks (MOFs) packed in the column have been a promising candidate as the stationary phase for high performance liquid chromatography (HPLC). However, the direct packing of irregular MOF powder could raise some problems like high back pressure and low column efficiency in the HPLC separation. In this work, UiO-66 capable of separating xylenes was supported effectively on the surface of the monodisperse spherical silica microspheres by one-pot method. The hybridization of UiO-66 and silica microspheres (termed UiO-66@SiO2 shell–core composite) was prepared by stirring the suspension of the precursors of UiO-66 and COOH terminated silica in the N,N-dimethylformamide with heating. The shell–core composite material UiO66@SiO2 was characterized by SEM, TEM, PXRD and FTIR. Then, it was used as a packing material for the chromatographic separation of xylene isomers. Xylene isomers including o-xylene, m-xylene and p-xylene were efficiently separated on the column with high resolution and good reproducibility. Moreover, the UiO-66@SiO2 shell–core composites packed column still remained reverse shape selectivity as UiO-66 possessed, and the retention of xylenes was probably ascribed to the hydrophobic effect between analytes and the aromatic rings of the UiO-66 shell. The UiO-66@SiO2 shell–core composites obtained in this study have some potential for the separation of structural isomers in HPLC.