Activated carbon materials are promising adsorbents both for pre- and post-combustion CO2 capture, due to their high specific surface areas and excellent mechanical and thermal stability. However, while carbon-based adsorbents can usually adsorb a large volume of CO2 at ambient temperature, their capacity decreases markedly at elevated temperatures and low CO2 partial pressures. ,In this study, the efficacy of KOH activation in improving the CO2 capture has been investigated. A range of spherical carbons having unifrom diameters of 0.5 to 1 mm were synthesised from different precursors using a novel hydrothermal process, and they were then activated at different temperatures with diffderent KOH/carbon mass rations between 1 and 5. The results demonstrate that KOH activation significantly improves CO2 adsorption. At 30 oC and a CO2 partial pressure of 0.15 bar, the CO2 uptakes of the KOH-activated carbon beads were found to be 2-3 times higher for phenolic resin (PR)-derived carbons (1.9 mmol/g) and 3-4 times higher for polyacrylonitrile (PAN)-based carbons (2.4 mmol/g) than their respective steam activated carbons. In comparison, at a CO2 partial pressure of 1 bar, the capacity of KOH-activated carbons reached 3.6 mmol/g for the PR-derived carbons and 4.8 mmol/g for the PAN-based carbons, again much higher than their steam-activated counterparts (1.6 to 2.2 mmol/g).

Performance-enhanced activated spherical carbon adsorbents for CO<sub>2</sub> capture

247th National Meeting (2014)

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Performance-enhanced activated spherical carbon adsorbents for CO2 capture

Performance-enhanced activated spherical carbon adsorbents for CO₂ capture