Sorption capacity and stability of mesoporous magnesium oxide in post-combustion CO2 capture

Mesoporous magnesium oxides with a high surface area (672-686 m(2)/g) were synthesized by an aerogel method and subsequently evaluated for CO2 capture efficiency under ambient-temperature sorption and intermediate-temperature regeneration. The effects of one-step (MgO-1) and four-step (MgO-4) calcination methods on the as-prepared MgO samples were evaluated with respect to textual properties and CO2 sorption capacity at various temperatures (30-350 degrees C). The as-prepared MgOs showed greater than 10 wt% of CO2 sorption at 30 degrees C, showing very fast sorption of more than 7 wt% CO2 within 5 min. The cyclic stability of the sorbents was tested by using CO2 sorption at 30 degrees C and N-2 regeneration at 450 degrees C. The sorption performance of MgO-1 was more stable and higher than that of MgO-4, but the surface area and pore volume were still reduced. The cyclic sorption capacity became 6.1 wt% at the condition of mixture gas sorption (CO2/N-2: 15/85 vol%) and CO2 regeneration. Since inter-crystallites coupling plays an important role in pore formation as well as stability, calcination condition can contribute to preventing the degradation level of performance and textural properties of sorbents. (C) 2017 Elsevier B.V. All rights reserved.