The MgO/Al2O3 sorbent for CO2 capture under low temperatures was investigated in a fixed bed. It was found that, with MgO loading of 10 wt %, MgO/Al2O3 sorbent showed a maximum CO2 capture capacity, which originated from the balance of physical adsorption and chemical absorption of the sorbent. The CO2 capture capacity increased with the water vapor at first and then decreased. Typically, the total CO2 capture capacities were as high as 0.97 and 1.36 mmol/g, with water vapor concentration of 0 and 13 vol %, respectively, at 60 °C with 13 vol % CO2. The high CO2 concentration could be approached by the multi-stage absorption/desorption cycles, during which the sorbent could be regenerated at 350 °C and maintained stable even after 5 cycles. In addition, a deactivation model was proposed that gave good predictions of the CO2 breakthrough curves. Results showed that sorption rate parameters obtained in the presence of water vapor were found to be larger than the corresponding values in the absence of water vapor. It was possibly caused by increasing the reactivity of the sorbent prior to the sorption of CO2 in the presence of water vapor.

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