Stable ionic liquid/Zr-MOF co-modified silica microspheres: Facile construction strategy and promising chromatographic applications

Abstract

The stability of porous metal-organic frameworks (MOFs) as ideal materials for adsorption and separation has always been a key concern. In this study, an ionic liquid (IL) with excellent properties synthesized under solvent-free conditions was used to modify Zr-MOF@SiO2 for the first time to enhance the stability and improve the separation ability of Zr-MOF@SiO2 for chromatographic applications. The IL serves a dual purpose of supporting the backbone structure of Zr-MOF and acting as a ligand to coordinate with Zr(IV). This facile construction strategy ensures that the overall structural framework of the IL/Zr-MOF composite is more stable. Additionally, the presence of IL with imidazolium and carboxyl groups can facilitate efficient chromatographic separation by providing multiple interaction mechanisms. The results shows that the separation performance of the IL/Zr-MOF composite is significantly superior to that of the original Zr-MOF. Furthermore, the obtained new IL/Zr-MOF@SiO2 column exhibits appreciable stability, repeatability and reproducibility, which also performs well in the analysis of real samples with no significant matrix effects, demonstrating good reliability of the developed method. This study proposes a facile strategy for cleverly synthesizing a novel IL/Zr-MOF@SiO2 as an efficient chromatographic separation material, thereby potentially broadening the application of Zr-MOF in separation science. The facile preparation and promising application of IL/Zr-MOF may also offer a new possibility for employing MOF-based composite materials as effective liquid chromatographic stationary phases.