HKUST-1 silica aerogel composites: novel materials for the separation of saturated and unsaturated hydrocarbons by conventional liquid chromatography

Abstract

HKUST-1 silica aerogel composite (HKUST-1@SiO₂) has been studied as a stationary phase for the efficient separation of unsaturated hydrocarbons from saturated aliphatics by conventional liquid chromotography (LC). HKUST-1@SiO₂ has been prepared via an advanced sol–gel method and subsequent drying in supercritical CO₂ to minimize the deterioration of the individual properties of the MOF and silica aerogel structures and tune its properties to be acceptable for flow mode. The synthesized composite was characterized by X-ray diffraction, FT-IR spectroscopy, XPS, scanning electron microscopy with EDAX mapping and low-temperature nitrogen adsorption. According to these data, the composite represents physically dispersed domains of HKUST-1 in the silica aerogel network. It was shown that the HKUST-1@SiO₂ composite can be used as a highly efficient stationary phase for conventional liquid chromatographic separation of cyclohexene or benzene from cyclohexane. This is the first time a MOF composite has been used for the separation of organic molecules by LC, demonstrating new vistas for the application of these materials in the flow mode.