The solvent and zinc source dual-induced synthesis of a two dimensional zeolitic imidazolate framework with farfalle-shape and its crystal transformation to zeolitic imidazolate framework-8

Exploring new zeolitic imidazolate frameworks (ZIFs) with specific topologies and pore structures is significant to extend applications and improve performances. In this work, a new farfalle-shape ZIF with the order hierarchical structure (named as ZIF-F) was easily built with zinc acetate and 2-methylimidazole (MeIm) in aqueous system at room temperature. The synthesis mechanism of ZIF-F is the dual-induction interaction by solvent and zinc source based on the synthesis protocol of ZIF-8. The prepared ZIF-F is a 3-5 μm dispersible particle constructed from numerous nanoplates with the same building units as ZIF-8. ZIF-F has richly 4 nm inter-particle spacing with the 0.1074 cm3 g-1 total pore volume and exhibits the high thermo- and solvent-stability. It’s worth noting that the crystal transformation could occur from ZIF-F to ZIF-8 in methanol via dissolution-recrystallization route. For the adsorption of Congo red (CR), ZIF-F performs the better adsorption capacity (182.82 mg g-1) than ZIF-8 (149.25 mg g-1) with the 6 times higher adsorption rate than that of ZIF-8, because of the positive effect of larger pore size and hierarchical structure.