(229a) Design and Development of Mesoporous K-MgO/Rgo Composite Sorbents for High Temperature CO2 Capture with Enhanced Uptake and Kinetics

Effective CO₂ capture is essential for mitigating emissions from hard-to-decarbonize industries such as cement and steel. The flue gas streams from these facilities are usually at high temperature (> 100-150 °C), which necessitates development of efficient sorbent materials and processes specifically for this temperature window. In this study, we report development of a highly mesoporous MgO (566 m²/g surface area and ~0.9 cm³/g mesoporous volume) modified with potassium (K) and integrated with reduced graphene oxide (rGO), namely rGO@K₂₀-MgO, for enhanced adsorption capacity and kinetics at 150 °C. The results showed that while the mesoporous K₂₀-MgO support with 20 wt% K exhibited a CO₂ uptake of 3.71 mmol/g, the rGO integration led to enhanced uptake at 5.17 mmol/g for rGO@K₂₀-MgO, which was nearly three times that of pristine mesoporous MgO at 150 °C. Furthermore, the adsorption rate enhanced from 0.032 min^-1 for mesoporous MgO to 0.134 min^-1 for rGO@K₂₀-MgO. The enhanced CO₂ capture performance of rGO@K₂₀-MgO composite sorbent could be attributed to its higher basicity (stemmed from K doping) and lower diffusional resistances (upon incorporation of rGO sheets) as confirmed by CO₂-TPD analysis. Additionally, we evaluated the dynamic performance of rGO@K₂₀-MgO composite sorbent with a multicomponent feed mixture (200 ppm SO₂, 200 ppm NO, 30% CO₂, and 69.96% N₂) and achieved stable adsorption performance across multiple cycles