CO2 capture: Tuning cation-anion interaction in urethane based poly(ionic liquids)

Abstract

Abstract The development of new urethane based poly(ionic liquids) (PILs) is a promising solution to address CO 2 capture. The obtainment of low cost polyurethane based PILs using different ionic liquids cations fosters the emergence of new materials for CO 2 capture. The synthesized PILs were characterized by GPC, FTIR, NMR, DSC, TGA, DMTA and AFM. CO 2 sorption capacity was gravimetrically assessed in a magnetic suspension balance. In addition, ab initio simulations were performed. Experimental and simulation results allow understanding the varying performance of the polymeric anion with the bmim, TBA, and TBP cations in CO 2 sorption. A successful compound for gas capture must exhibit the weakest possible cation-anion coordination and smaller molecular masses. Better CO 2 sorption capacity was achieved for the cation TBA as compared to TBP and bmim (the amounts of CO 2 sorption at 50 bar and 303.15 K were 162 mgCO 2 /g for the PU-bmim, 168 mgCO 2 /g for PU-TBP and 226 mgCO 2 /g PU-TBA). At lower pressures, these compounds present a high CO 2 sorption capacity (at 0.82 bar of pressure and 303.15 K PU-bmim presented a CO 2 sorption of 9.4 mgCO 2 /g; PU-TBP 15.7 mgCO 2 /g and PU-TBA 16.1 mgCO 2 /g). The compounds PU-TBP and PU-TBA presented higher sorption values as compared to literature.