Selective CO2 separation through physicochemical absorption by triazole‐functionalized ionic liquid binary absorbents

Abstract The selective separation of CO 2 from CH 4 ‐containing gases is crucial to produce clean energy gases. In this study, triazole anion‐functionalized ionic liquids (TAFILs) were designed by combining low molecular weight cations with triazole anions containing N electronegative site and further mixed with physical solvents to form physicochemical absorbents. The results indicated that [Cho][Triz]/TMS (80 wt%/20 wt%) not only absorbs 0.125 g CO 2 /g absorbent equal to that of 30 wt% MEA solution at 40°C and 1 bar, but also has low enthalpy of −35.76 kJ/mol less than half of 30 wt% MEA solution. Simultaneously, a super high CO 2 /CH 4 selectivity of 191.0, higher than most of the reported absorbents, is obtained for [Cho][Triz]/TMS solvents. Such great performance of CO 2 separation was attributed to relatively weak chemical and physical interaction between CO 2 and TAFIL binary absorbents. This study may provide novel promising ionic liquid absorbents for CO 2 capture applications from clean energy gases.