A comparative study of CO2 and CH4 adsorption using activated carbon prepared from pine cone by phosphoric acid activation

Adsorption of pure carbon dioxide and methane was examined on activated carbon prepared from pine cone by chemical activation with H3PO4 to determine the potential for the separation of CO2 from CH4. The prepared adsorbent was characterized by N-2 adsorption-desorption, elemental analysis, FTIR, SEM and TEM. The equilibrium adsorption of CO2 and CH4 on AC was determined at 298, 308 and 318 K and pressure range of 1-16 bar. The experimental data of both gases were analyzed using Langmuir and Freundlich models. For CO2, the Langmuir isotherm presented a perfect fit, whereas the isotherm of CH4 was well described by Freundlich model. The selectivity of CO2 over CH4 by AC (CO2: CH4=50: 50, 298K, 5 bar), predicted by ideal adsorbed solution theory (IAST) model, was achieved at 1.68. These data demonstrated that pine cone-based AC prepared in this study can be successfully used in separation of CO2 from CH4.