Application of PEI–K2CO3/AC for capturing CO2 from flue gas after combustion

•A novel PEI–K2CO3/AC sorbent was prepared with the co-impregnation method.•The coupling characteristics of PEI and K2CO3 in the sorbent are expounded.•Both PEI and K2CO3 contribute to the total CO2 capture capacity of PEI–K2CO3/AC.•PEI–K2CO3/AC presents high CO2 capture capacity and long-term stability.•PEI–K2CO3/AC should be considered as a new option for post-combustion CO2 capture.

The capture of CO2 from flue gas after combustion using solid sorbents is one of the efficient options for reducing CO2 emissions from fossil fuel-fired power plants. To satisfy the requirement of large quantities flue gas treatment, the CO2 capture capacities of the solid sorbents must be focused on. In order to obtain a sorbent with high CO2 capture capacity, a novel PEI–K2CO3/AC sorbent was prepared by impregnating potassium carbonate (K2CO3) and polyethylenimine (PEI) on activated carbon (AC) in this work. The CO2 capture performance of this sorbent was investigated using a fixed bed reactor system. The CO2 capture capacity of PEI–K2CO3/AC with the total K2CO3 and PEI loadings of 50 wt% was measured as 3.60 mmol CO2/g under the condition of 60 °C, 8% CO2 + 10% H2O. In addition, this sorbent is proved to be regenerable and stable during 5 cycle CO2 sorption–desorption tests. Compared with K2CO3/AC (loading of 58 wt%) and PEI/AC (loading of 43 wt%), PEI–K2CO3/AC presents higher CO2 capture capacity and long-term stability. Therefore, PEI–K2CO3/AC should be considered as a new option for capturing CO2 from flue gas after combustion.

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