Sustainable biomass-based carbon adsorbents for post-combustion CO2 capture

Sustainable carbon adsorbents have been produced from biomass residues by single-step activation with CO2. The activation conditions were optimised to develop narrow micropores in order to maximise the CO2 adsorption capacity of the carbons under post-combustion conditions. The equilibrium of adsorption of pure CO2 and N-2 was measured between 0 degrees C and 50 degrees C up to 120 kPa for the outstanding carbons. The CO2 adsorption capacity measured at low pressures is among the highest ever reported for carbon materials (0.6-1.1 mmol g(-1) at 15 kPa and 25-50 degrees C), and the average isosteric heat of adsorption is typical of a physisorption process: 27 kJ mol(-1). Dynamic experiments carried out in a fixed-bed adsorption unit showed fast adsorption and desorption kinetics and a high CO2-over-N-2 selectivity. These adsorbents are able to separate a mixture with 14% CO2 (balance N-2) at 50 degrees C, conditions that can be considered as representative of post-combustion conditions, and they can be easily regenerated. (c) 2013 Elsevier B.V. All rights reserved.