Aliphatic amine-modified recombinant endoskeleton UiO-66 efficiently enhances CO2 capture performance

Abstract

Rational chemical modification engineering of metal-organic frameworks (MOFs) is an effective means to improve their CO2 capture efficiency. In this study, we prepare UiO-66 MOF impregnated with different types of aliphatic amines using solvothermal and impregnation techniques, respectively, and investigated their performances in CO2 adsorption and CO2/N2 separation using the isothermal adsorption method. Aliphatic amines successfully chemically modifies UiO-66, and their molecules effectively occupied the pores of the UiO-66 framework, which has been confirmed by material characterization, experiments, and DFT-FMO calculations. There are significant improvements in the ability to capture CO2 when aliphatic amines were added to UiO-66 compared to pure UiO-66 (1.39 mmol/g up to 2.11 mmol/g-2.53 mmol/g), attributed to the different types and numbers of amines, and there were also differences in the Zr metal clusters and BDC ligands. Meanwhile, The material has better CO2/N2 adsorption IAST selectivity(98) because its surface area is changed and N2 does not interact specifically with the adsorbent. Furthermore, the CO2 adsorption capacity remains constant across multiple adsorption cycles, highlighting the adsorbent's stability and reliability during repetitive CO2 capture. This study provides new ideas and perspectives for improving the CO2 capture efficiency of UiO-66.