Olive stones based carbon foam: synthesis, characterization and application on post-combustion CO2 adsorption

In the present paper, the performance of carbon foams to adsorb CO2 in post-combustion conditions using a thermo-gravimetric analyzer was investigated. Two types of carbon foams were prepared in this study from molten sucrose and activated carbon powder as foaming and foam setting agents by adding or not of nitric acid. Both carbon foams were subjected to chemical and textural characterization such as FT-IR, Boehm titration, SEM and physical adsorption. Then, these materials were evaluated for CO2 adsorption in a binary mixture (10% CO2 + 90% N2), representative of post-combustion conditions, at two temperatures 25 and 50 °C. The obtained carbon foams present a hierarchical macro–micro pore structure with narrow-micropores in the cell walls and micropores sizes of less than 0.6 nm. The produced adsorbent materials showed a high and competitive CO2 uptake in pure flow at 0 °C with a CO2 adsorption capacity of up to 3 mmol g−1. In addition, carbon foams adsorbents showed high CO2/N2 selectivity in binary (CO2 + N2) adsorption/desorption tests thanks to their very narrow microporosity not accessible for N2 molecules but accessible to CO2. Thus, biomass-based carbon foams are promising candidates to selectively capture CO2 in post-combustion conditions.