Isotherm and Thermodynamic Analysis of Carbon Dioxide on Activated Carbon

In this study, commercial Norit® SX2 activated carbon has been evaluated as a solid adsorbent for carbon dioxide (CO2) capture at the post-combustion conditions, which are at an ambient pressure and low temperatures (< 120oC). The CO2 equilibrium adsorption capacity is assessed through a static volumetric technique. This solid adsorbent is characterized in terms of elemental analysis, nitrogen physisorption, as well as surface morphology. The CO2 adsorptive property of the commercial Norit® SX2 demonstrates a reduction in the amount of CO2 adsorbed at an elevated temperature, and accordingly, it indicates that CO2 adsorption is a physical adsorption process and demonstrates a behavior of an exothermic reaction, which consistent with the thermodynamics analysis. Different isotherm models are applied to mathematically model the CO2 adsorption, and on basis of the regression coefficient (R2), the Freundlich model provides a perfect fit to the experimental data, owing to closeness of the R2 to unity. The result obtained in this study can serve as a benchmark while searching for inexpensive and superior activated carbon production in future studies.