1 Carbon adsorbents for CO2 capture from bio-hydrogen and biogas streams: Breakthrough adsorption study

The biological production of H2 by dark fermentation is being extensively investigated due to the great potential of the two-phase hydrogen/methane fermentation process for recovering energy from carbohydrate-rich wastes. However, the purification of the bio-hydrogen and biogas obtained is needed to produce high-purity H2 and CH4 streams appropriate for industrial application. In this study, the performance of three activated carbons (No1KCla-600, No1KClb-1000 and No2OS-1000), synthesized from phenol-formaldehyde resins, as potential adsorbents for CO2 capture from bio-hydrogen and biogas streams has been evaluated under dynamic conditions. Adsorption-desorption cycles by means of temperature swings were conducted at ambient temperature and atmospheric pressure with CO2/H2 (40/60 and 70/30 vol. % at normal conditions) and CO2/CH4 (50/50 vol. % at normal conditions) binary gas mixtures in a purpose-built fixed-bed set-up. The performance of the resin-derived carbons to separate CO2 was superior to that of reference commercial carbons in terms of CO2 uptake, breakthrough time and column efficiency. These adsorbents presented hig