A low viscosity poly(ethylene imine) modified by 1, 2-epoxybutane: synthesis and post-combustion CO2 capture performance

In the present work, a low viscosity polymer n EB-PEI 1800 ( n  = 0.22, 0.29, 0.35) is synthesized for CO 2 capture. n EB-PEI 1800 is obtained by partially modifying poly(ethylene imine) (PEI 1800 ) with 1, 2-epoxybutane (EB) and is characterized by FT-IR, elemental analysis and liquid state 13 C NMR. The physical properties, density and viscosity, of aqueous n EB-PEI 1800 solutions with weight fraction w of 30% at the temperatures ranging from (293.15 to 313.15) K are reported. Additionally, CO 2 capture performance by aqueous n EB-PEI 1800 solution is examined. CO 2 absorption loading, average absorption rate, desorption loading, average desorption rate and desorption efficiency in a variety of aqueous n EB-PEI 1800 solution ( w  = 5%, 10%, 15%, 20% and 30%) are investigated at different temperatures. The stability of PEI-based absorbent is also examined by four absorption–desorption cycles. The results reveal that modification can adjust the physical properties of n EB-PEI 1800 solutions. 0.29 EB-PEI system has the lowest viscosity and is favorable for CO 2 capture. 20% aqueous 0.29 EB-PEI solution provides excellent cycling stability and desorption performance, especially desorption efficiency, increasing by 55% compared to PEI system at 393.15 K.