Selective CO2 separation through physicochemical absorption by
triazole-functionalized ionic liquid binary absorbents
Abstract
The selective separation of CO2 from CH4-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 absorb 0.125 g CO2/g absorbent equal to that of 30 wt% MEA
solution at 40 °C and 1 bar, but also have low enthalpy of -35.76 kJ/mol
less than half of 30 wt% MEA solution. Simultaneously, superhigh
CO2/CH4 selectivity of 191.0 higher than most of reported absorbents is
obtained for [Cho][Triz]/TMS solvents. Such great performance of
CO2 separation was attributed to relatively weak chemical and physical
interaction between CO2 and TAFIL binary absorbents. This study may
provide novel promising IL absorbents for CO2 capture applications from
clean energy gases.