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

Abstract

Mesoporous magnesium oxides with a high surface area (672–686 m2/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 °C). The as-prepared MgOs showed greater than 10 wt% of CO2 sorption at 30 °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 °C and N2 regeneration at 450 °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/N2: 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.