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

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.