Unveiling the impact of synthesis routes on water and ethanol sorption performance of ZIF-71 and ZIF-93

Abstract

Interest in the large-scale applications of metal–organic frameworks (MOFs) has grown in the last 10 years. However, applying MOFs in real life situations remains challenging due to the high cost associated with mass production and their potential negative effects on the environment. In this study, ZIF-71 and ZIF-93 frameworks were synthesized at room temperature using greener solvents (water, methanol, and ethanol) and via mechanochemical synthesis. Structural and textural analyses revealed that the structural and textural properties of the ZIFs were mostly preserved, with the mechanochemically prepared samples exhibiting slightly reduced crystallinity and microporosity compared to those prepared using established solvothermal synthesis methods. The water and ethanol sorption performance study of the samples revealed comparable water and ethanol uptake for the entire ZIF-93 series and for the sample prepared by methods from the literature. The same applies to the ZIF-71 series, except for one ZIF-71 sample synthesized using the liquid-assisted ball milling method, which showed reduced water and ethanol uptake due to partial degradation of the structure during the sorption study. The stability study of the four best-performing samples over up to 20 sorption/desorption cycles revealed that the samples prepared using ball milling and the precipitation method, maintained their initial capacity throughout the evaluated cycling program, suggesting promising long-term performance.