Novel metal–organic framework of UTSA-16 (Zn) synthesized by a microwave method: Outstanding performance for CO2 capture with improved stability to acid gases

Abstract

Herein we present a novel metal–organic framework (UTSA-16 (Zn)), where cobalt in the framework is replaced by zinc via microwave irradiation, with significantly improved stability in humid air and acid gases and better selectivity (CO2/N2) than the original Co-containing framework. The synthesis was performed using microwave irradiation by changing the irradiation time from 1 to 6h. The integrities of the frameworks were assessed with scanning electron microscopy for particle morphology, powder X-ray diffraction for crystal integrity, Brunauer–Emmett–Teller for structural properties, and thermogravimetric analysis for thermal stability. An irradiation time of 4h produced 4h-UTSA-16 with an outstanding CO2 adsorption capacity of 4.71mmol/g at 298K and 1bar and with CO2/N2 selectivity of 118. The improvement in stability and CO2/N2 sorption selectivity of UTSA-16 (Zn) over the parent UTSA-16 (Co) was not compromised by decreases in CO2 uptake after exposure to humid air, SO2, and NO2 gases. Further, analysis of production cost showed that the UTSA-16 (Zn) is superior to other adsorbents for CO2 capture.