Separation of H2CO2 and CH4CO2 binary mixtures by zeolite-like imidazolate frameworks

The separation of H2CO2 and CH4CO2 is relevant for the CO2 capture from pre-combustion processes of fossil fuels and from natural gas streams where it is an undesirable component, respectively. This contribution discusses the separation of these binary mixtures using packed columns of five different zeolite-like imidazolate frameworks, Zn(Im)2, Co(Im)2, Zn(MIm)2, Co(MIm)2, and Zn0.54Co0.46(MIm)2 where Im = Imidazolate and MIm = 2-methyl imidazole. As evaluation tests, elution profiles, at different temperatures, recorded by Inverse Gas Chromatography were used. The data analysis is carried out considering the materials structural features and the possible adsorbate-adsorbent interactions involved in the adsorption forces. These materials are able to separate these binary mixtures with the best performance for Zn(Im)2, Co(Im)2 and Zn0.54Co0.46(MIm)2. This study was complemented by the materials structural characterization and evaluation of their thermal and textural properties.