Phenol-Formaldehyde Resin-Based Carbons for CO₂ Separation at Sub-Atmospheric Pressures

The challenge of developing effective separation and purification technologies that leave much smaller energy footprints is greater for carbon dioxide (CO₂) than for other gases. In addition to its involvement in climate change, CO₂ is present as an impurity in biogas and bio-hydrogen (biological production by dark fermentation), in post-combustion processes (flue gas, CO₂-N₂) and many other gas streams. Selected phenol-formaldehyde resin-based activated carbons prepared in our laboratory have been evaluated under static conditions (adsorption isotherms) as potential adsorbents for CO₂ separation at sub-atmospheric pressures, i.e., in post-combustion processes or from biogas and bio-hydrogen streams. CO₂, H₂, N₂, and CH₄ adsorption isotherms at 25 °C and up to 100 kPa were obtained using a volumetric equipment and were correlated by applying the Sips model. Adsorption equilibrium was then predicted for multicomponent gas mixtures by extending the multicomponent Sips model and the Ideal Adsorbed Solution Theory (IAST) in conjunction with the Sips model. The CO₂ uptakes of the resin-derived carbons from CO₂-CH₄, CO₂-H₂, and CO₂-N₂ at atmospheric pressure were greater than those of the reference commercial carbon (Calgon BPL). The performance of the resin-derived carbons in terms of equilibrium of adsorption seems therefore relevant to CO₂ separation in post-combustion (flue gas, CO₂-N₂) and in hydrogen fermentation (CO₂-H₂, CO₂-CH₄). View Full-Text