Carbon Nanofiber-Supported K₂CO₃ as an Efficient Low-Temperature Regenerable CO₂ Sorbent for Post-Combustion Capture

This study focuses on regenerable sorbents for post-combustion CO 2 capture at low temperature (373 K). K 2 CO 3 loaded on three different supports, carbon nanofibers (CNF), alumina (γ-Al 2 O 3 ), and activated carbon (AC), was investigated. K 2 CO 3 –CNF revealed excellent properties as CO 2 sorbent, displaying capacities of 1.2–1.6 mmol g –1 and fast desorption kinetics at low temperatures (423 K). This temperature was too low to completely regenerate K 2 CO 3 –Al 2 O 3 and K 2 CO 3 –AC, and consequently, these sorbents lost 8% and 50%, respectively, of their capacity after the first absorption–desorption cycle. K 2 CO 3 –CNF could be regenerated to restore 80% of its capacity with a low energy input, estimated at 2–3 GJ/ton CO 2, which is competitive to currently used amines.