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 CO2 capture at low temperature (373 K). K2CO3 loaded on three different supports, carbon nanofibers (CNF), alumina (γ-Al2O3), and activated carbon (AC), was investigated. K2CO3–CNF revealed excellent properties as CO2 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 K2CO3–Al2O3 and K2CO3–AC, and consequently, these sorbents lost 8% and 50%, respectively, of their capacity after the first absorption–desorption cycle. K2CO3–CNF could be regenerated to restore 80% of its capacity with a low energy input, estimated at 2–3 GJ/ton CO2, which is competitive to currently used amines.